19ARC709L - Performance Evaluation Tools For Sustainable Buildings - Notes - Prashanthini Rajagopal

SRM Institute of Science & Technology
(Deemed to be university u/s 3 of UGC Act, 1956)

School of Architecture & Interior Design
19ARC709L - PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS
STUDY MATERIAL
M.ARCH
(2021 – 2022)
ODD SEMESTER
19ARC709L - PERFORMANCE EVALUATION

TOOLS FOR SUSTAINABLE BUILDINGS
2ND YEAR – IIIRD SEMESTER
2019 REGULATION
PRASHANTHINI RAJAGOPAL
ASSISTANT PROFESST
SAID – SRM INSTITUTE OF SCIENCE AND TECHNOLOGY
PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

FACULTY: PRASHANTHINI RAJAGOPAL 1|Page
UNIT 1: INTRODUCTION TO BUILDING PERFORMANCE EVALUATION

Introduction to the Emerging role of performance evaluation in building design
and master planning
INTRODUCTION:
A buildings performance indicates how efficiently it performs its functions in terms of physical, social
or environmental considerations.
Examples of physical efficiency parameters:
- Heat loss
- Energy Use
- Water Use
- Water tightness
- Structural Performance
- Fire performance
There are multiple criteria as to how today’s buildings are assessed. These may include the
following:
• Sustainability (eco-friendly materials, energy consumptions, building fabric retention of heat
through the use of insulation or designing for optimal glazing performance, water efficient
systems such as grey water recycling)
• Provide healthy environment to endure comfort through control of temperature, humidity
and ventilation
• Impact on the ecology due to construction
• Acoustical performance inside the buildings and impact on outdoors
• Operational cost of the building
• Water proofing and tightness
• Layout optimization – privacy, sunlight, views, occupant circulation etc
• Lighting requirement, glare, design and comfort – Dynamic study
• Air flow or ventilation study – Dynamic study
• Thermal and energy performance – Dynamic study
•
ACTIVITIES AND PHASE:
▪ Building Performance Evaluation (BPE) includes a range of activities that is conducted in a
systematic and rigorous manner.
▪ These include:
▪ Research
▪ Measurement
▪ Comparison
▪ Evaluation
▪ Feedback
The above activities take place in every phase of a building’s life cycle which includes:
Planning
▪ Briefing/Programming

▪ Design
▪ Construction
▪ Occupancy
▪ Recycling
Performance Evaluation through Simulations: THE NEED

▪ Emerging buildings these days require operational requirements of the users to be fulfilled
along with the building being sustainable in nature.
▪ This is an enormous challenge to architects and other professionals associated in the industry
as they must take into account the various dynamic processes around us:
▪ Global Climate Change
1. Growing Occupant Needs
2. Comfort Expectations
3. Depletion of fossil fuels
4. Increasing flexibility of organizations
5. Indoor Environment and health
▪ In order to manage and control all these above measures required a robust building and
system solutions through an integrated approach
▪ In the design stage various trial and error/ research/ guidance must take place to enable the
designer to create a high performing sustainable building or urban space.
▪ The parameters that are usually considered are:
1. Temperature and Thermal Indices
2. Energy Consumption

3. Lighting
4. Ventilation
5. Air Quality
6. Acoustics
7. Traditionally designed buildings are largely unsuitable for addressing the above
parameters to meeting an optimal output.
▪ This is because they assume a static case, which usually consists of designing for the most
extreme condition.
▪ These calculations are based on analytical methods – which seeks to provide an exact solution
for a simplified model of reality.
Performance Evaluation through Simulations: COMPUTATIONAL MODELING AND SIMULATION

▪ The emerging role in the performance evaluation of building happens in the design process
itself, where building models are created and simulated
▪ This method is multi-disciplinary, problem oriented and has a wider scope
▪ Simulations assume a dynamic (Usually hourly basis which is continuous in time), boundary
conditions and is based on numerical methods
▪ This provides an approximate solution of a realistic model of complexity
▪ Computational simulations are a powerful analytic tool – however quality of simulation results
is difficult to ensure.
▪ A diverse range of disciplines give rise to the power and complexity of building performance
model and simulation. These include:
1. Physics
2. Mathematics
3. Material Science
4. Biophysics
5. Human Behavior
6. Environmental Science
7. Computational Science

Understanding Architectural Computation for Performance Evaluation

Thermal and Energy Models and Simulations
▪ Energy models of multiple design alternatives can assist in finding the optimal solution.
▪ In order to generate model the following workflow is required:
1. Define Site, Location and Climate – This step requires the designer to download and upload
the weather data file (usually EPW file) with hourly observation data for a specific weather
station.
2. Create Building Geometry and Thermal Zoning – Intricacies of building geometry is drafted
directly into the energy simulation engine. 3D architectural models are transitioned to a
energy model with material properties assigned to the building envelope.
3. Building Orientation/Site Layout/Solar Shades – Model is made with adjacent building, site
obstruction and any structures that block direct solar radiation. Building orientation is set up
within the site boundary. Solar shading calculations is usually made at this stage and results
are carried over to the dynamic thermal simulations.
4. Internal Gains and Operational Profile – Internal heat gain from equipment within the
building/room is assigned. This includes office equipment, residential appliances, lighting
power and other equipment associated with occupant use. Operational profiles are inputs
about time of day and hours of usage of the above. Sensible and latent heat gain associated

with occupant metabolic rate is also assigned by entering number of occupants and the clo
values.
5. Building Envelope Properties – The thermophysical properties of building fabric materials are
entered into the energy model. External and internal properties of the walls, floors, roofs,
windows, doors and roof lights are assigned. However, the most important property to be
entered is the U-Value of the material construction of the above – this represents the overall
heat transfer coefficient, material thickness, density and solar reflectivity.
6. Air Tightness - Defines how well sealed the building is from external air conditions. Energy
model results must reflect the impact of air infiltration through the façade. This has a major
impact on the heating and cooling loads of the building.
7. Domestic Hot Water System – The consumption levels are based on the number of occupants
and hot water fixtures. The model may include gas or electric heaters, solar panels, circulation
pumps and storage tanks. The parameters include the efficiency of the system, operating
power of the pump, volume of storage tank and heat losses.
8. HVAC Model – Highly detailed model of the air conditioning and ventilation system is
assigned. In order to mimic the operational and controls of the actual system is entered
through the operation of all mechanical equipment such as chillers, air-handling-units, fans,
chilled beams, cooling towers and pumps. Calculations made through efficiency of the systems
and thermal loads base on hourly simulations.
9. Optimizing HVAC Operation – Used to minimize energy consumption and carbon emissions.
Optimization can be done through various criteria – annual energy consumption, carbon
dioxide, fresh air rates, thermal comfort levels (PMV) etc.
10. Add Renewable Energy System – Renewable energy sources can be added directly to the
model – solar panels, solar hot water system, wind turbines and geothermal systems. Check
to see if software is cable.
B. Indoor Air Quality Simulation (IAQ)

▪ Several criteria can be assessed using certain simulation tools
▪ Key design criteria used: thermal comfort, indoor air contaminants, air change effectiveness
and age of air.
C. CO2 Concentration
▪ One of the major indicators of air quality
▪ Building occupants release carbon dioxide – increased levels indoors can be unhealth
▪ Insufficient renovation of air is one of the major causes for Sick Building Syndrome
▪ Frequent outdoor supply air is critical but needs to be optimal, since outside air needs to be
processes at right temperature and humidity conditions by HVAC.
▪ Model must specify if outside air is supplied through air-conditioning ducts or naturally
ventilated (operable windows)
D. Thermal Comfort
▪ Thermal comfort calculations are directly derived from the thermal model details given. It is
assessed based on indoor air and radiant temperature, relative humidity and air velocity in
specific occupant metabolic rates and clothing.

▪ Predicted Mean Vote (PMV) – thermal scale that runs from Cold (-3) to Hot (+3), system
developed by Franger.
▪ Recommended acceptable PMV is between -0.5 and +0.5 for interior ventilated space
▪ Naturally ventilated spaces can have wider temperature range following an adaptive comfort
scale.
E. Lighting Comfort (Visual Comfort – Daylighting and Glare Analysis)

▪ Natural light can be used to reduce energy use and sensible heat loads associated with internal
artificial lighting.
▪ Use of dynamic lighting control to maintain optimal levels can bring down the energy
consumption
▪ Daylight Factor can be used in the initial stages of design (static calculation)
▪ Dynamic simulation or Daylight Autonomy provides designers with details of illuminance
levels across different spaces through the year
▪ Daylight model processes the 3D geometric model along with the material properties assigned
to the internal/external surfaces. ,The material properties used are: - Solar Reflectivity (R),
material emissivity for opaque surfaces, Visible Light Transmittance (VLT) and Visible Light
Reflectance (VLR) for glazing elements.
E. Lighting Comfort (Visual Comfort – Daylighting and Glare Analysis)

▪ Natural light can be used to reduce energy use and sensible heat loads associated with internal
artificial lighting.
▪ Use of dynamic lighting control to maintain optimal levels can bring down the energy
consumption
▪ Daylight Factor can be used in the initial stages of design (static calculation)
▪ Dynamic simulation or Daylight Autonomy provides designers with details of illuminance
levels across different spaces through the year
▪ Daylight model processes the 3D geometric model along with the material properties assigned
to the internal/external surfaces. ,The material properties used are: - Solar Reflectivity (R),

material emissivity for opaque surfaces, Visible Light Transmittance (VLT) and Visible Light
Reflectance (VLR) for glazing elements.
▪ Daylight sensos can be used to measure illuminance at a particular point in the interior
surfaces – can be integrated with the energy model to dim the lights when lux levels
increased the required.
▪ Results for daylight and glare can be presented on the working plan or 3D view –
Perspective, Hemispherical Fish-eye and Angular Fish-eye.
F. VENTILATION
▪ Air exchange Effectiveness relates to how efficiently the supply air is distributed through the
built spaces. Measures the age of air in occupied parts of the building to the age of air in a
perfectly mixed ventilation system
▪ Age of Air – average amount of time that has elapsed since the air has entered a specific
location within the built space.
▪ If air change effectiveness is 1 ach – outdoor air flow rate to the ventilated space is same as
minimum design requirements.
▪ Simulations are performed by Computational Fluid Dynamics. Configurations done through
setup of finite mesh and boundary conditions that can mimic the actual mechanical and
natural ventilation systems.

Performance Audit and Rating Systems – GRIHA, LEED, IGBC and BREAM
GRIHA
▪ GRIHA is an ingenious rating system (India) developed by TERI
▪ GRIHA is an acronym for Green Rating for Integrated Habitat Assessment.
▪ GRIHA is the Sanskrit word for ‘Abode”
The Objectives of GRIHA:

1. Minimizing the overall ecological impact posed by the building, reducing resource
consumption and waste generation
2. Evaluated the entire life cycle of the building to assess the environmental
performance of the built space.
3. Seeks to strike a balance between energy and environmental principles
4. Reduce energy consumption while maintaining comfort conditions
5. Minimize destruction of natural area, biodiversity, habitats of species and reduce
soil loss from erosion
Five ‘R’ Philosophy

1. REFUSE to adopt international styles, materials, products, especially when local options are
available
2. REDUCE dependence on energy intensive appliances, systems, processes etc.
3. REUSE products, materials and use traditional technologies to reduce the cost of the
building
4. RECYCLE All types of waste generated from the building site during the construction,
operation and demolition stage.
5. REINVENT practices, design process and systems native to India and create global example,
as opposed to India following international examples.
GRIHA ELIGIBILITY:
▪ All pre-design/design stage buildings except industrial complexes are eligible for certification
under GRIHA.
▪ ADaRSH (Association for Development and Research of Sustainable Habitats), GRIHA
secretariat evaluates whether the project is eligible for rating or not
GRIHA PROCESS:
▪ Registration of building project is done using the website (http://www.grihaindia.org)
▪ The registration process requires the following information:
1. Application forms
2. List of Submissions
3. Score Points
4. Weightage system
5. Online documentation
EVALUATION PROCEDURE
1. Pre-Documentation Stage – Team from ADaRSH meet with the Integrated Design team of
the client and determine the points that are going to be targeted for the project

2. Post Documentation Stage - Documentation proof of the the targets in the criteria being
achieved is submitted for evaluation.
Evaluation is done by third party evaluators – they determine the final rating that is to be
awarded to the building
GRIHA VARIANTS:
▪ SWAGRIHA (100-2499 sq.m)
▪ GRIHA (2500 – 1,50,000 sq.m)
▪ GRIHA LD (Over 50 hectares)
GRIHA RATING CRITERIA

▪ Points are earned for meeting the criteria
▪ Each criteria under the environmental category
is assigned points.
▪ GRIHA is a 100 point system
▪ Certification is based on one star to five stars.
GRIHA ENVIRONMENTAL CATEGORY

▪ Sustainable Site Planning
▪ Construction Management
▪ Energy Efficiency
▪ Occupant Comfort
▪ Water Management
▪ Solid Waste Management
▪ Sustainable Building Materials
▪ Life Cycle Costing
▪ Socio-Economic Strategies
▪ Life Cycle Costing
▪ Performance Metering and Monitoring
▪ Innovation

FACULTY: PRASHANTHINI RAJAGOPAL 10 | P a g e

Examples of Simulation Software accepted by GRIHA
USE OF SIMULATIONS IN GRIHA
Criterion 13: Optimize building design to reduce conventional energy demand

Commitment
Plan appropriately to reflect climate responsiveness, including adequate daylighting as well as efficient
artficial lighting.
▪ Perform artificial lighting simulation to demonstrate that the lighting levels in indoor spaces
are maintained as recommended in NBC 2005
Criterion 14: Optimize energy performance of building within specified comfort limits
Commitment
Ensure reduction in EPI up to 40% under a specified category.
▪ Minimum benchmark for energy performance index as per GRIHA
▪ Ensure that energy consumption in building under a specified category is 10%–40% less than
that benchmarked through a simulation exercise. (16 points)
▪ The energy systems includes air conditioners, indoor lighting systems, water heaters, air
heaters and air circulation devices.
▪ Annual energy consumption data for the building and the unmet comfort conditions for non-
AC area, as per GRIHA, supported by the simulation results from the software used.
LEED
▪ LEED was founded by United States Green Building Council in the year 1993
▪ It is a non-profit organization based in Washington DC
▪ It had a vision of achieving sustainability in building sector within a generation

The Objectives of LEED:

1. To define green building by establishing standards of measurement.
2. Promoting integrated design practices.
3. Recognizing environmental leadership in building industry.
4. To increase the awareness among customers by specifying the benefits of green
building.
LEED
▪ LEED rating system family can be divided into 5 categories:
1. Building Design and Construction (BD+C)
2. Interior Design and Construction (ID+C)
3. Building Operation and Management (O+M)
4. Neighborhood development (ND)
5. Homes Design and Construction

LEED Credit Categories

▪ Sustainable Sites
▪ Water Efficiency
▪ Energy & Atmosphere
▪ Materials and Resources
▪ Indoor Environmental Quality
▪ Innovation in Operations and Regional Priority
List of approved LEED software

▪ (Bold indicates it is mentioned within the LEEDonline v3 EAp2 forms)
▪ DOE2
▪ eQUEST
▪ Visual DOE
▪ EnergyPlus
▪ EnergyPro
▪ HAP (Carrier HAP)
▪ TRACE 700 (Trane TRACE)
▪ OTHER (see requirements of Appendix G, Section G2)
▪ BLAST (not mentioned within the LEED form, but listed in 90.1 section G2)
▪ IES (Integrated environmental solutions, listed in LEED Advanced energy modeling)

IGBC
▪ Indian Green Building Council (IGBC) was formed by the Confederation of Indian Industry
(CII) in 2001
▪ The council headquarters is in CII Green Business Centre, Hyderabad (India’s 1st Platinum
rated green building)
▪ Off-shoot of LEED to suit Indian context and conditions
IGBC Green New Buildings rating system is broadly classified into two types:
▪ 1) Owner-occupied buildings are those wherein 51% or more of the building’s built-up area
is occupied by the owner.
▪ 2) Tenant-occupied buildings are those wherein 51% or more of the building’s built-up area
is occupied by the tenants.
IGBC
▪ Certification levels are similar to LEED
▪ Certified, Silver, Gold, Platinum and Super Platinum

OBJECTIVES OF IGBC
▪ Water conservation
▪ Handling of consumer waste
▪ Energy Efficiency
▪ Reduced Use of Fossil Fuels
▪ Redes dependency of Virgin
Materials
▪ Health and Well-being of
Occupants



Simulation Approach to gaining credits

1. Demonstrate that the passive architecture measures implemented in the project has resulted in at
least 2% energy savings of total annual energy consumption (through whole building simulation
approach).
The approach shall address the following aspects, but not limited to:
▪ Climate-responsive concepts and design features (Eg: orientation, skylights, light wells,
courtyard, shaded corridors, shading devices, shading from trees & adjacent buildings,
pergolas, punched windows, extended louvers, horizontal and vertical landscaping)
▪ Passive cooling / heating technologies (Eg: wind tower, earth tunnel, geothermal
technologies)
2. 50 % of the regularly occupied spaces with daylight illuminance levels for a minimum of 110 Lux
(and a maximum of 1,100 Lux) in a clear sky condition on 21st September at 12 noon, at working plane
(through simulation or measurement approach)
▪ Upward Lighting: Design exterior lighting such that all site and building-mounted luminaires
produce a maximum initial illuminance values, as defined in ASHRAE Standard 90.1-2010.

▪ (AND)
▪ Lighting Power Density: The lighting power density should be reduced by 30% for building
facades and exterior areas vis-à-vis the ASHRAE Standard 90.1-2010 baselines, Section 9.4.3 -
Exterior Building Lighting Power (tradable & non-tradable surfaces).
3. Design the building to comply with ASHRAE Standard 90.1-2010, Appendix - G (without
amendments) through Performance based approach (Whole building simulation). Simulation is to be
carried out at comfort temperatures of 24 + 2 deg C.
Points are awarded based on energy cost percentage savings as detailed below:
BREEEAM
▪ It was launched in 1990 by UK’s Building Research Establishment (BRE)
▪ It sets standards for the environmental performance of buildings through design,
specification, construction and operational phases.
The Objectives of BREEAM
1. Ensure quality through sustainability impacts.
2. Use quantified measures for determining sustainability.
3. Adopt a flexible approach
4. Use best available science and practice (quantifying) and cost-effective performance
standard
5. Seek economic, social and environmental gains jointly
6. Framework should meet the ‘local’ context
7. Integrate construction professionals
8. Adopt third party certification
9. Adopt existing industry tools, practices and other standards to support developments
in policy and technology
10. Use stakeholder consultation




Introduction to Performance Audit: Introduction to Building Performance

Simulation Tools
ModelIT enables you to build a 3D analysis model with or without CAD data. It is the principle
modelling tool within the Virtual Environment. Any information stored can be easily shared and
manipulated within any VE application.
Geometry Creation
▪ Use different 3D objects to quickly build your model: Rectangular, Non-Rectangular, Spherical,
Hemispherical, Cylindrical, Pyramid

▪ Full range of editing features: cut, move, copy, paste, rotate, push/pull, merge, split
▪ Shading surfaces can be assigned: adjacent buildings, topographical shades, local shades
▪ Windows, doors or holes can be defined on any surface
▪ Components can be added from the library or created: tables, chairs, trees, columns etc.
▪ Attributes can be modified for individual rooms or groups of rooms
▪ Rooms can be assigned to different modelling ‘layers’ for easy inspection
▪ Geometry can be visualised and edited from standard views; plan, front, back, right, left,
axonometric
▪ Locks and snaps make it easy to draw and modify rooms: grid, endpoint, midpoint and nearest
point
▪ Site location and model orientation can be easily set and modified
▪ Ruler & protractor tools
▪ Open Street Map (OSM) connection allows the import of surrounding buildings and geometry
▪ ShapeFile and gml import support
▪ VE Start page includes starter geometry and schematic geometry wizard (select from standard
floor plan layouts)
Building Template Manager

• Each space you create in the model is automatically assigned generic room information which
is organised by the Building Template Manager
• All information is editable – you can even create your own library of templates
• The templates contain information such as occupancy profiles, constructions, surface colours
and building control information
• You can access the relevant parts of the room information from VE application, and add
additional information specific to that application.
• The process is extremely fast and efficient, minimising the risk of data entry errors
• Rooms can be grouped for easy assignment and editing of data
• The system allows you to fast start projects or help prepare project bids without significant
data input
Fast Track Functions
• Rooms within models can be conveniently grouped to help analysis and assignment of data
• Room and surface attributes are automatically calculated, displayed and are editable on
integrated views when selected: name, ID, floor area, wall area, eternal opening area
• Percentage glazing, sill/window heights or window arrays can be changed globally
• Automatic pitched roof generator
• Floor and ceiling height editor
• Partition tool to quickly split existing zones
• Duplicates of repeated window/door arrays can be created to quickly transfer duplicated
information
• Drag Face function allow volumes to be resized quickly
• DXF trace over function
• Storey extruder to create multiple stories from a single zone or multiple spaces
• Zone split to take any existing zone/s and partition vertically into different spaces for stratified
zone or floor/ceiling plenums

• Option to assign constructions and/or Macroflo properties to openings based on current

selection criteria
ModelViewerII Visualisation Options

▪ Fly through capability
▪ Dynamic pan, zoom and orbit control
▪ View from any perspective or distance
▪ Textures, rendering and sketch style options
▪ X-ray display mode
▪ View colours can be customised
▪ Easily export images & videos for use in client demonstrations
▪ Simplified camera path functionality for video creation and reporting
▪ Adjustable sky background
▪ Ability to turn on/off grid lines to give perspective and scale
Solar Shading / Solar Arc Options

▪ View real time shadows on 3D Model – choose the date and time you want
▪ Visualize sun position in the sky in relation to the 3D Model. You can choose to toggle on or
off views which show: azimuth, altitude, defined time, sun rise and sun set times, autumn
equinox, summer & winter solstices
▪ Video animations can be created across time periods
▪ Both can be viewed on a minute by minute basis across the year
▪ Modify the size of both the arc and the sun to match the model footprint, should the default
settings not be suitable
ApacheSim is comprised of the following tools:

1. Apache
2. ApacheEngine
3. Vista & VistaPro
4. ApacheView
5. ApachePro
6. ApacheLocate
7. Constructions Database
Calculations are based on first-principles models of heat transfer process and are driven by real
weather data.
Data Entry Options

▪ Extensive database of global weather
▪ Data detailing layer-by-layer thermo-physical properties of building elements
▪ Comprehensive data on glazing systems including angle-dependent transmissivity and
absorptivity
▪ Option to define electrochromic properties of glazing and shading devices that dynamically
vary in response to model conditions within simulation
▪ Ability to define renewable energy generators: PV (parametric, free standing and high
concentration), wind generators and CHP systems

▪ Sensible and latent gains from lights, equipment and occupants

▪ Natural ventilation, mechanical ventilation and infiltration
▪ Plant operation profiles and efficiency characteristics
▪ Powerful facilities for assigning and editing time-varying room data such as plant, casual gains
and air exchanges
▪ Database of constructions
▪ Time-series profiles
▪ Tabular Edit interface for entering properties of thermal templates, room thermal properties,
HVAC systems and constructions. Gives ability to quickly enter data, review inputs and
includes option to export and import *.csv files (e.g. Excel)
▪ Faster project setup using Master Template and Design Options features. The Master
Templates feature delivers bulk data copying & rapid automatic seeding of data in to a project
while the Design Option feature provides a means to make specific and targeted changes to
specified data in a project
▪ Sub-metering options within ‘Energy Sources & Meters’ – create meters for all the fuels that
exist in the model then sub-meter and collate this information in VistaPro

Output Options
ApacheSim’s output database can be browsed to interrogate every aspect of building thermal
performance, from individual surface temperatures to annual energy consumption.
Results accessible via graphical views of the building with interrogation of data possible at a
hierarchy of levels:
1. Building
2. Room
3. Surface
4. Opening
▪ Multiple tables and graphs are produced for results analysis including monthly summaries,
ranges or user-specified synopses
▪ Chart axes can be user defined and results plotted as absolute values or else divided by floor
area or room volume
1. Room performance indicators include:
2. Room temperatures: air, mean, radiant, dry, resultant
3. ISO comfort indices: predicted mean Vote (PMV) and percentage of people
Dissatisfied (PPD)
4. Room Loads: heating, cooling, humidification, dehumidification
5. Loads breakdowns: casual and solar gains, conduction and ventilation losses, plant
inputs
6. Surface temperatures
Energy Consumption: Annual, Monthly, hourly
Building and System performance indicators include:

1. Totals of room and ventilation loads: heating cooling, humidification,
dehumidification
2. HVAC Loads
3. Systems energy form Idealised plant heating and cooling energy or from ApacheHVAC
linked simulation
4. Energy Consumption: Annual, Monthly, hourly
5. Carbon Emissions for system and building; option to breakdown by fuel
6. Tariff analysis: operational cost reductions linked to energy consumption & fuel tariffs
▪ Multiple results can be displayed simultaneously or aggregated.
▪ Psychrometric Charts with options to display room thermal comfort and HVAC node state
display or simulation weather file data
▪ Results can be exported to other windows applications for use in reports, presentations and
further analysis
Content Manager provides a central area to access and store all VE reports. VistaPro can
generate the following reports:
1. Heating and Cooling Report - Provides a monthly summary of the building systems energy
consumption, CO2 consumption, basic comfort checks and peak loads breakdown.
2. Room and Zone Loads Report for ApacheHVAC - Generate loads report for ASHRAE
methods loads analysis run for Rooms, HVAC Zones or HVAC System Sizing analyses.

3. Energy Report - Gives a graphical summary of the energy simulation results including;
Energy End Use Consumption breakdown (Site Energy, Source Energy and CO2), Annual
Energy Usage dashboard, Energy Use Intensity (EUI) chart and Energy Flows Sankey,
associated Costs overview and view of Peak Electricity & Fossil Fuel consumptions
alongside any Generators onsite.
RADIANCE
This application uses sophisticated ray-tracing techniques to produce a physically accurate
representation of light distribution. It can take into account:
• Position of your building and site
• Time of day and date
• Sky conditions
• Material properties
• Shading surfaces
• Adjacent buildings
Simulations can include detailed complex geometry and a wide variety of material types. Both
luminance (what your eye sees) and surface or working plane illuminance (what the surface receives)
can be analyzed.
Input Options
▪ Parameters
1. Date & time
2. Sky conditions (from selection of internationally recognised conditions)
3. Working plane (if required)
4. Eye & focus positions (apply graphically or numerically)
5. Glare threshold
6. Inclusion / exclusion shading surfaces: adjacent buildings, topographical shades, local shades
7. Option to choose sky resolution to speed up calculation of daylight coefficients
▪ Surface Properties
1. Integrated to project construction database
2. Apply colour – including components and shading surfaces
3. Select material properties from a pre-defined list
4. Create patterns of varying textures
5. Bidirectional Scattering Distribution Function (BSDF)
Components
1. Add from the global components library and amend if required
2. Create your own
3. Define which to include / exclude
▪ Image Properties
1. Field of view
2. Size
3. Quality
▪ Luminaires (if using in conjunction with LightPro)
1. Define which to include / exclude

2. queue any number of simulations and run at pre-defined times for increased efficiency (e.g.
outside office hours)
3. include components such as tables, chairs and people to make images more realistic
Output Options
▪ Lux Levels (Illuminance)
1. Rendered image or tabular text
2. Figures displayed at any point on the image – grid
3. At a defined working plane height
4. Contour line, contour band and false colour images
5. Jpg & bmp file format export
▪ Daylight factors (Illuminance)
1. Rendered image or tabular text
2. Figures displayed at any point on the image – grid
3. At a defined working plane height
4. Contour line, contour band and false colour images
▪ Glare (Luminance)
1. Rendered images with glare indices overlay
2. Table showing Guth Index, CIE Index, Unified Glare Index
3. Daylight glare probability index
▪ Climate Based Daylighting Metrics
1. Useful Daylight Illuminance (UDI)
2. Spatial Daylight Autonomy (sDA)
3. Annual Sunlight Exposure (ASE)
4. Coloured analysis bands and contours can be shown on 3D ModelViewer
FlucsDL Output Options

▪ 3D model visualisation of Light Level plots
1. select rooms to display
2. select room surfaces, working planes and task areas to display
3. display as contour lines, false colour, threshold or as grey-shaded grid cells
4. Foot Candle or Lux options
▪ 3D model visualisation of Daylight Factor plots
1. select rooms to display
2. select room surfaces, working planes and task areas to display
3. display as contour lines, false colour, threshold or as grey-shaded grid cells
▪ Display of Light Levels and Daylight Factors can be toggled independently
▪ Summary Table showing minimum, maximum and average levels, plus uniformity and
diversity information
▪ Threshold Table showing individual room threshold levels and building area-weighted %
above threshold
▪ Results easily exported, copied or printed for use in client reports

Introduction of simulation strategies related to thermal generation in a built

form
▪ Building thermal simulation tools predict the thermal performance of a given building and the
thermal comfort of its occupants.
▪ In general, they support the understanding of how a given building operates according to
certain criteria and enable comparisons of different design alternatives
▪ Evaluation of thermal comfort involves assessment of at least six factors:
1. Human activity levels
2. Thermal resistance of clothing
3. Air temperature
4. Mean radiant temperature

5. Air velocity
6. Vapor pressure in ambient air
Based on the evaluation in this study of various tools, some information required for thermal
simulation includes as input data such as:
1. Building geometry, including the layout and configuration of the space (surfaces and
volumes)
2. Grouping of rooms in thermally homogenous zones
3. Building orientation
4. building construction, including the thermal properties of all construction elements
5. Building usage including functional use, internal loads and schedules for lighting,
occupants, and equipment, heating, ventilating, and air conditioning (HVAC) system
type
6. Operating sharacteristics, space conditioning requirements, utility rates, and
weather data.
The result of the thermal simulation engine is an integrated model or comprehensive information
and it should allow another program to read or to analyze further. The output data or the simulation
result may be presented in a text, graph or code.
The output results may include:

• Assessment of the space and building thermal performance for compliance with regulations
and targets;
• Overall estimate of the energy used by the space and for the building and an overall estimate of
the energy cost;
• Time-based simulation of the energy use of the building and time-based estimate of utility costs;
• Lifecycle estimate of the energy use and cost for the building.



Introduction of simulation strategies related to visual comfort of a built form

▪ Prediction of light behavior is ideal for calculation with computers. Formulas stating it take
▪ considerable time to solve by hand. Complexity grows proportionally to that of the scene
being computed.
▪ Lighting simulation can still be divided into two main areas, even though they mutually benefit
from developments in each of them.
▪ The first one is photorealistic rendering, involved with production of artistic images.
▪ The second field, and focus of this review, is physically based visualization (also known as
predictive rendering). It deals with accurate representation and prediction of reality under
given conditions and following physical laws


Lighting Metrics:
Material Properties to be defined by the designer:

1. Reflectance
2. Transmittance
3. Roughness
4. Colour
5. Object type
1) ILLUMINANCE is a photometric term that quantifies light incident on a plane or a surface and can
include contributions from electric light and daylight. The Illuminating Engineering Society (IES)
recommends horizontal and vertical illuminance targets to ensure adequate illumination and safety
for occupants of various ages. Illuminance is expressed in lux (lumens per square meter) or footcandles
(lumens per square foot). 1 footcandle = 10.76391 lux.

2) USEFUL DAYLIGHT ILLUMINANCE (UDI) is the annual occurrence of illuminances that is within a
“useful” range for occupants.

3) DAYLIGHT FACTOR (DF) is the ratio of the illuminance at a point on a plane in a room due to the
light received from a sky of assumed or known luminance distribution, to that on a horizontal plane
due to an unobstructed hemisphere of this sky. Direct light is excluded from both values of
illuminance, so a cloudy sky is modeled (e.g. CIE Overcast Sky). DF calculations provide the same
results regardless of time of day (shown below) or orientation. DF is expressed as a percentage.
0-2% DF is inadequately light and so electric lighting is required

2-5% DF is adequately light, but electric lighting may be required during some of the time
>5% DF is a well-lit space and electric lighting should not be required during daytime periods.
Glare may be an issue.
4) UNIFORMITY is the ratio of minimum illuminance to average illuminance (EMIN/EAVE). For side-lit
rooms, uniformity should be in the range of 0.3 – 0.4. For top-lit spaces such as an atrium, a uniformity
of 0.7 could be expected. In the example below, light-redirecting blinds are ‘throwing’ light further
into the room while eliminating the excessive direct daylight under the window. A Bidirectional
Scattering Distribution Function (BSDF) is assigned to the window to represent the daylight redirecting
blinds.

5) VERTICAL SKY COMPONENT is a measure of the amount of sky visible from a center point of a
window, though excludes direct light (i.e. uses a CIE Overcast Sky). A window that achieves 27% or
more is considered to provide good levels of daylight. VSC is often viewed from the exterior of the
model building and is particularly appropriate in a congested or urban environment. Windows
shown is green below pass the VSC threshold.
6) SPATIAL DAYLIGHT AUTONOMY (sDA) is the annual sufficiency of daylight levels in a space. sDA
examines the percentage of an analysis area (e.g. working plane) that meets a minimum illuminance
level (e.g. 300 lux) for a specified fraction of the operating hours per year (e.g. 50% of the
operational hours of the year).

7) LUMINANCE measures light that is leaving a surface in a particular direction and considers the
illuminance on the surface and the reflectance of the surface. Luminance is sometimes referred to as
brightness and is measured in candelas/m2 (also known as nits) or candelas/ft2. (also known as foot-
lambert). 1 cd/ft2 = 10.76391 cd/m2.
8) DAYLIGHT GLARE PROBABILITY (DGP) is a robust glare metric whereby glare sources are detected
by contrast ratios with direct daylight considered, as are specular reflections. DGP is a newer Glare
metric (2006) when compared against older glare metrics such as UGR, DGI, CGI & VCP.
DGP ranges are:

<0.35 = Imperceptible Glare
0.35-0.4 = Perceptible Glare
0.4-0.45 = Disturbing Glare
>0.45 = Intolerable Glare

Introduction of simulation strategies related to embodied energy

performance of different components and parameters
Embodied energy is the total energy required for the extraction, processing, manufacture and
delivery of building materials to the building site. Energy consumption produces CO2, which
contributes to greenhouse gas emissions, so embodied energy is considered an indicator of the
overall environmental impact of building materials and systems.
When selecting building materials, the

embodied energy should be considered
with respect to:
1. The durability of building materials
2. How easily materials can be
separated
3. Use of locally sourced materials
4. Use of recycled materials
5. Specifying standard sizes of
materials
6. Avoiding waste
7. Selecting materials that are
manufactured using renewable
energy sources



Understanding energy analysis for building covering approximate methods

and correlation methods
APPROXIMATION METHOD
▪ Preliminary design of a complex system often involves exploring a broad design space or
region of design variable values.
▪ Many detailed analysis programs are available for use in the latter stages of design, but they
can be extremely expensive for exploring broad regions.
▪ One solution has been to simplify the simulations and obtain data from more approximate
simulations. For these approximate simulations, accuracy is sacrificed to reduce
computational time.
▪ However, when it is desirable to explore a large design space that includes broad ranges of
design variables, repeated approximate simulations still generate substantial computational
loads.
▪ The finite difference approach, used here for approximate simulations (AS), is a numerical
technique for solving two- or three-dimensional heat transfer problems.
▪ Finite difference models are based on difference equations that approximate continuous
variables as quantities at discrete points or nodes on a grid
▪ Approximation method subdivides a complex problem space, or domain, into numerous
small, simpler pieces (the finite elements) whose behavior can be described with
comparatively simple equations.
▪ In energy analysis, dynamic finite element analysis is used as the forces applied to the system
change of time – for example the heal flow through a system

▪ The model needs not to be highly flexible for real-time building energy modeling, in facilitating
the building operation and control design optimization.
▪ The update cycle granularity is generally within hourly-basis or daily basis.
▪ As a result, the design operation bounds are usually covered by the training data.
▪ A quick and accurate approximation model is preferable than a cumbersome time-consuming
model.
▪ Used for used for design optimization, design space exploration, sensitivity analysis, what-if
analysis and real-time engineering decisions.
▪ Response surface methodology (RSM) is typically useful in the context of continuous
optimization problems and focuses on learning input–output relationships to approximate the
underlying simulation by a surface
▪ Realistic Model
CORRELATION METHOD
▪ The correlation coefficient method is a measure of the strength and direction of the
relationship between two variables, and it can take on any value between –1.0 and +1.0.
▪ That is, the correlation coefficient can be decomposed into its sign (positive or negative
relationship between two variables) and the magnitude or strength of the relationship (the
higher the absolute value of the correlation coefficient, the stronger the relationship).
▪ For energy analysis the correlation may be taken for tested and simulated relation or between
the U-value and energy etc.
▪ Simplified correlation methods are powerful tools to compare both the energy performance
of buildings and the efficiency of different HVAC control systems.
Understanding energy analysis for analytical methods and numerical method

ANALYTICAL METHOD
▪ Analytical methods – seeks to provide an exact solution for a simplified model of reality.
▪ They are often static and do not seek a dynamic representation of data.
▪ Answers contribute to a specific time of day and with a singular heat flow calculation made
for that time alone
▪ These do not have dynamic computer-based simulations and are often conducted manually –
traditional designing
▪ The most extreme condition is often taken for calculation, which does not give a year-round
picture or performance of the energy consumption in the building
▪ Energy calculations are often made with simplistic formulas of heat transfer for a specific day
and time.
▪ Input conditions are an approximate value based on weather data file.
▪ Energy calculation (year) will not show an accurate output as conditions change year-round
(dynamic)
▪ The simplistic calculation used – heat flow path, conduction, convection, solar transmittance,
radiation etc.
▪ Design solutions may be provided for the chosen time and date of the study but may perform
differently during the other times – making design development short lived.

▪ Example – Shading device made for the hottest day and time – But how does this work on the
other dates or times?
▪ However, pre-design work may often take the help of analytical method and later
modifications made through computer aided dynamic simulations.
NUMERICAL METHOD
▪ Predictions of physical phenomena in buildings are carried out by using physical models
formulated as a mathematical problem and solved by means of numerical methods, aiming at
evaluating, for instance, the building thermal or hygrothermal performance by calculating
distributions and fluxes of heat and moisture transfer.
▪ Therefore, the choice of the numerical method is crucial since it is a compromise among
(i) the solution accuracy
(ii) the computational cost to obtain the solution
(iii) the complexity of the method implementation.
▪ An efficient numerical method enables to compute an accurate solution with a minimum
computational run time (CPU).
▪ A modelling approach that uses any numerical methodology other than just simulation. This
can include measurements, experimentation and calculation from first principles
▪ A variety of building energy analysis and simulation tools are increasingly used to determine
peak heating and cooling loads, size thermal plant, anticipate annual energy consumption and
analyse thermal comfort.
▪ Numerical solution techniques are considered the most flexible for building energy simulation.
▪ When applied to the differential equations modelling energy flows in buildings, they give rise
to a system of non-linear algebraic (difference) equations.
▪ In order to evaluate numerical methods for building energy simulation, the problem has been
characterized mathematically and comprehensive test problems (equation sets) with these
characteristics have been prepared.

UNIT 2: MODELLING FOR PASSIVE SYSTEMS

Modeling and experimental techniques for building assessment/ evaluation
and design
INTRODUCTION:
▪ A buildings performance indicates how efficiently it performs its functions in terms of physical,
social or environmental considerations.
▪ Examples of physical efficiency parameters:
- Heat loss
- Energy Use
- Water Use
- Water tightness
- Structural Performance
- Fire performance
There are multiple criteria as to how today’s buildings are assessed. These may include the
following:
▪ Sustainability (eco friendly materials, energy consumptions, building fabric retention of heat
through the use of insulation or designing for optimal glazing performance, water efficient
systems such as grey water recycling)
▪ Provide healthy environment to endure comfort through control of temperature, humidity
and ventilation
▪ Impact on the ecology due to construction
▪ Acoustical performance inside the buildings and impact on outdoors
▪ Operational cost of the building
▪ Water proofing and tightness
▪ Layout optimization – privacy, sunlight, views, occupant circulation etc
▪ Lighting requirement, glare, design and comfort – Dynamic study
▪ Air flow or ventilation study – Dynamic study
▪ Thermal and energy performance – Dynamic study
There are 3 parts for modelling and energy simulation:

1. An “engine” contains the calculations and algorithms to perform simulations. The engine uses
a description of building characteristics, operations, and ambient conditions to simulate
physical processes and calculate critical information such as annual building energy use and
peak loads.
2. A 2-D or 3-D modeler allows geometry to be entered into a software package. This can be
done using a separate program to develop a model or the building performance software may
have an interface that functions as a plug-in to a 2/3-D modeler. Or the building performance
software has a 2/3-D modeler “built-in.”
3. A user interface allows the user to work with an engine and 2-D or 3-D modeler to create
energy simulations and outputs.

▪ Building energy simulation software uses data inputs provided by the user and assumptions
about building systems and schedules.
▪ The assumptions may be built into the software such that the user has little knowledge or
control; or they may be presented as simplified inputs, such as templates with predefined
defaults.
▪ The user may choose from these defaults as inputs, especially early in design, which can make
the software easier and faster to use.
▪ Also, in early design, software may use partial information to perform single aspect
simulations that answer questions about specific options such as massing, orientation, solar,
shading, daylight, glare, and natural ventilation.
The shoebox model is one such example. It represents a small, discrete, and isolated portion of a
building and that portion’s energy performance. Shoebox models can provide useful information
regardless of their simplified inputs such as geometry, internal loads, and HVAC.
▪ The accuracy of the energy simulation is directly dependent on the accuracy of inputs.
▪ The more information available for the person performing the simulation—whether an
architect or BPS professional—the more useful the results.
▪ Part of building performance simulation involves the explicit identification of assumptions,
such as schedules, comfort standards, window-to-wall ratio, material and insulation
characteristics, light level inputs, and passive strategies.
▪ Common inputs to reach thermal comfort targets (e.g., air temperature, mean radiant
temperature, relative humidity) are generally assumed based on ASHRAE Standard 55 –
Thermal Environmental Conditions for Human Occupancy.
▪ For projects using natural ventilation, with an abundance of glass in extreme climates, or with
low-energy aspirations, additional conversations are warranted with the design team and the
client to consider adjusting the targeted comfort range.


Hotel Hanoi - Vietnam
The design team wanted to use simple vertical rods in the

façade, balancing the need for views from the hotel rooms
with the need for shade. An annual solar study was
performed during the early design phase to compare two
options to a baseline without shade. Average daily values for
the summer period are shown. Option 1 provides a 19
percent reduction in solar gains. Option 2 has more rod
density located to block the summer afternoon sun and
provides a 34 percent reduction in solar gains while still
allowing views. Option 2 was selected for further
development and analysis with building performance
simulation.
Retail - Middle East

The goal was to maximize outdoor comfort in the courtyards
of a shopping mall in the middle east. Predicted mean vote
(PMV) (see Part 6.3 Thermal Comfort) was calculated at
different times and dates. Shade is a known prerequisite to
achieve thermal comfort in the seating area during warm
days. This study shows three different options: option 1, is a
simple overhang; option 2 features a 1000 mm vertical shade;
and option 3, a 2000 mm vertical shade. The images show,
for each option, both the annual percentage of sun hours on
the surface sensors in the terrace and the percentage of the
surface with direct sun exposure distributed hourly over the
year. With this analysis it is possible to understand the
distribution of solar intensity over time and over the surface
of the seating area. The study demonstrated that the
overhang was not enough to provide shade to this space and
additional operable shading was needed.

Shopping mall food and beverage area

Melbourne, Australia
The client wanted to minimize direct sun

exposure on the food and beverage area
located below a glass canopy. Several
options for minimizing direct solar gain
were studied at the master plan phase.
Three options rely on extending the
dimension of the structure underneath the
glass. The dimensions of the “solar
responsive” option are generated
parametrically from the centroids of the
areas indicated in the summer solar study.
Two options are based on sawtooth
design, and the most effective is the
“30sawtooth.” By angling the sawtooth to
minimize summer direct gains, it reduces
solar gains by 83 percent. The
“30sawtooth” option was selected for
further development and testing
Retail Abu Dhabi, United Arab Emirates

This shading system was proposed for a
glass canopy in a hot, dry and sunny
location. The goal was to provide daylight
with minimal direct solar gain. Climate
analysis indicated it was important to
reduce solar gains all year, especially in the
summer. Several options were compared
during early conceptual design, with
annual or seasonal solar studies. One of
the summer studies is shown. Option A
had the lowest direct sunlight exposure
(38 percent), blocking 62 percent of direct
sun. Additional reductions in solar gains
are achieved when combined with low
solar-heat-gain -coefficient (SHGC) glass.
Option A was selected for further
development and testing for daylight and
energy.

Event space Harbin, China

The client wanted maximum
transparency for an event space in a
city with a very cold winter and a
warm summer. Control of heat
losses and gains through this mostly
transparent envelope were very
important considerations. Summer
and winter solar studies helped
define envelope areas that needed
more opacity in the summer to
block solar gains and more
transparency in the winter to
provide more solar gains. An
operable louver system in key areas
to block solar gains in the summer
and provide transparency for
greater solar gains in the winter is
proposed. Additionally, an annual
study (not shown here) helped
locate PV systems for maximum
solar production.
Competition for a hotel and mixed-

use development Anaheim,
California
The goal was to determine critical

façades and estimate potential
reductions in solar gains provided
by different shade options on the
building. Horizontal fins were
designed using the sun shading
chart in the Climate Consultant
program. The simulation shows 45
percent reduction of solar gains in
the south façade with horizontal
elements. The result was that shade
was implemented for the
competition proposal.

Basics of Thermal Comfort

▪ A building that is either too hot or too cold and does not provide thermal comfort for occupants
is also unlikely to meet its initial energy performance goals.
▪ Thermal comfort is influenced by a number of factors at different times of the day, month, and
year.
▪ Outdoor conditions play a role, as well as ventilation.
▪ Where we are in a space, what we are doing, what we are wearing, and how we interact with a
space also play a role.
▪ The highly subjective nature of human behavior and comfort complicate thermal comfort
simulation efforts.
"That condition of mind which expresses satisfaction with the thermal environment". A definition most
people can agree on, but also a definition which is not easily converted into physical parameters.
▪ The complexity of evaluating thermal comfort is illustrated by the drawing. Both persons
illustrated are likely to be thermally comfortable, even though they are in completely different
thermal environments. This reminds us that thermal comfort is a matter of many physical
parameters, and not just one, as for example the air temperature.
▪ Thermal environments are considered together with other factors such as air quality, light and
noise level, when we evaluate our working environment. If we do not feel the everyday working
environment is satisfactory, our working performance will inevitably suffer. Thus, thermal
comfort also has an impact on our work efficiency
There are many factors that can affect thermal comfort, including:
▪ Humidity levels
▪ Heat sources in the workplace
▪ Drafts, ventilation units and other
forms of airflow
▪ Floor level (heat always rises, so those
working on higher floors often
experience higher temperatures)
▪ Glazing units and proximity of working
near them
▪ Physical demand of the work
▪ Personal factors (clothing, gender,
personal preference).

Environmental Factors:
1. Air temperature: Is the temperature set between comfort limits, or what is reasonable for the
worker group.
2. Mean Radiant Temperature: Examples include: the sun, fire, electric fires; ovens; kiln walls;
cookers; dryers; hot surfaces and machinery, molten metals etc.
3. Air velocity: the speed of air moving across the employee and may help cool them if the air is
cooler than the environment but can cause discomfort is the air movement is excessive.
4. Humidity: a range of 40-60%, with an optimum level of 50% is recommended. Low humidity can
induce feelings of dry and itchy eyes, runny nose and lethargy whilst high humidity levels reduce
a person’s ability to self-regulate temperature through sweating and can contribute towards
heat fatigue/stress.
5. Clothing insulation: Wearing too much clothing or PPE is often a primary cause of heat stress
even when the temperature is not considered warm or hot. If the clothing does not provide
enough insulation, the employee may be at risk from hypo thermia in cold conditions.
6. Metabolic heat: The more physical the work, the more heat that is produced. Metabolic heat is
variable in individual’s dependant on their age, weight, fitness level etc so maintaining a
constant temperature is vital.
METABOLIC HEAT
▪ The metabolism is the body’s motor, and the
amount of energy released by the metabolism is
dependent on the amount of muscular activity.
▪ Normally, all muscle activity is converted to heat
in the body, but during hard physical work this
ratio may drop to 75%.
▪ If, for example, one went up a mountain, part of
the energy used is stored in the body in the form
of potential energy. Traditionally, metabolism is
measured in Met (1 Met = 58.15 W /m 2 of body
surface).
▪ A normal adult has a surface area of 1.7 m 2 , and
a person in thermal comfort with an activity level
of 1 Met will thus have a heat loss of
approximately 100W.
▪ Our metabolism is at its lowest while we sleep
(0.8 Met) and at its highest during sports
activities, where 10 Met is frequently reached.

CLOTHING INSULATION
▪ Clothing reduces the body’s heat loss. Therefore,
clothing is classified according to its
▪ insulation value. The unit normally used for measuring
clothing’s insulation is the Clo unit, but
▪ the more technical unit m2°C/W is also seen
frequently (1 Clo = 0.155 m2°C/W).
MEAN RADIANT TEMPERATURE

▪ The Mean Radiant Temperature of an environment is defined as that uniform temperature
of an imaginary black enclosure which would result in the same heat loss by radiation from
the person as the actual enclosure.
▪ Measuring the temperature of all surfaces in the room is very time consuming, and even
more time consuming is the calculation of the corresponding angle factors. That is why the
use of the Mean Radiant Temperature is avoided if possible.
▪ The Globe Temperature, the Air Temperature and the Air Velocity at a point can be used as
input for a Mean Radiant Temperature calculation

▪ If the thermal comfort in a workplace is

not perfect, how far from perfect is it? Or
within what limits should we maintain
temperature and humidity to enable
reasonable thermal comfort?
▪ The answers to these questions can be
obtained from the PMV-index (Predicted
Mean Vote).
▪ The PMV-index predicts the mean value
of the subjective ratings of a group of
people in a given environment.
▪ The PMV scale is a seven-point thermal-
sensation scale ranging from -3 (cold) to
+3 (hot), where 0 represents the
thermally neutral sensation.
▪ Even when the PMV-index is 0, there will
still be some individuals who are
dissatisfied with the temperature level,
regardless of the fact that they are all
dressed similarly and have the same level
of activity - comfort evaluation differs a
little from person to person
▪ To predict how many people are dissatisfied in a given thermal environment, the PPD-index
(Predicted Percentage of Dissatisfied) has been introduced.
▪ In the PPD-index people who vote -3, -2, +2, +3 on the PMV scale are regarded as thermally
dissatisfied. Notice that the curve showing the relationship between PMV and PPD never gets below
5% dissatisfied
▪ When evaluating a workplace, we often talk about the Comfortable Temperature ( t co ), which is
defined as the Equivalent Temperature where a person feels thermally comfortable.
▪ We rarely talk about comfortable humidity, this is partly due to the difficulty of feeling the humidity
in the air and partly due to humidity having only a slight influence on a person’s heat exchange
when they are close to a state of thermal comfort.
▪ If a room contains many people, wearing different types of clothing and carrying out different types
of activities, it can be difficult to create an environment which provides thermal comfort for all the
occupants.
▪ Something can be done by changing the factors that affect the thermal comfort locally, for example,
if the equivalent temperature is lower than the comfort temperature, the mean radiant
temperature can be increased by installing heated panels.
▪ People can also adapt to maintain comfort conditions
Modelling based on solar shading based on orientation and hierarchy of

massing in a site
▪ The climate of earth is driven by the energy input from the sun.
▪ For designers there are two essential aspects to understand:
1. apparent movement of the sun (the solar geometry)

2. energy flows from the sun and how to handle it (exclude it or make use of it).
▪ The earth moves around the sun on a slightly elliptical orbit.

▪ At its maximum (aphelion) the earth–sun distance is 152 million km and at its minimum
(perihelion) 147 million km.
▪ The earth’s axis is not normal to the plane of its orbit, but tilted by 23.5◦.
▪ Consequently, the angle between the earth’s equatorial plane and the earth–sun line varies
during the year. This angle is known as the declination (DEC)
▪ Whilst the above heliocentric view is necessary for understanding the real system, in building
problems the lococentric view provides all the necessary answers. In this view the observer’s
position is at the centre of the sky hemisphere, on which the sun’s position can be determined
by two angles
▪ Altitude and azimuth angles
Note: The path of the sun for the same location changes each day. The above
image illustrates the position and path of the sun during summer solstice,
equinox and winter solstice.

Note: For the same date and time, the sun-path is very different for
both these locations
Note: A 3D sun path overlaid keeping the building at the centre.

Notice how the sun path varies throughout the year This can play
a significant role choosing a building orientation, geometry,
position and size of fenestration, building material choice and
design of shading systems.
SUN-PATH DIAGRAMS:
▪ Sun-path diagrams or solar charts are the simplest practical tools for depicting the sun’s
apparent movement.
▪ The sky hemisphere is represented by a circle (the horizon). Azimuth angles (i.e. the direction
of the sun) are given along the perimeter and altitude angles (from the horizon up) are shown
by a series of concentric circles, 90◦ (the zenith) being the center

▪ The sun-path lines are plotted on this chart for

a given latitude for the solstice days, for the
equinoxes and for any intermediate dates
▪ The date-lines (sun-path lines) are intersected
by hour lines. The vertical line at the Centre is
noon
ALTITUDE ANGLES AND SUN-PATH:

▪ Altitude angles are represented as concentric
circles in the sun path diagram
▪ Altitude is the height of the sun above the
horizon measured in degrees
▪ Centre of the circle is 90 degree and
outermost circle is zero degrees
▪ Azimuth angles are represented as radial lines in the sun

path diagram representing the position of the sun in
plan
▪ Azimuth is the angle of the sun, usually from the
north, but may be reported from the South as well
▪ Usually starts at 0 degrees from north and makes its way
around the circle at regular intervals till it reaches full
360 degrees.

MONTH LINES IN SUN-PATH:

▪ These will be the heavy solid lines running horizontally,
though they are slightly curved.
▪ In terms of solar position, June and December are special
months.
▪ At the Summer and Winter solstice the sun is at it's
highest and lowest point, respectively.
▪ These two months have their own lines. Every other
month shares a line with it's opposite month.
▪ That's right, the sun is in the same position at 9am on the
21st day of February as it is at 9am on the 21st day of
October.
▪ The complete list of pairs is May/July, April/August,
March/September (these are the Equinox months),
February/October and January/November.
TIME LINES IN SUN-PATH:

▪ These are represented by the heavy solid lines running
vertically.
▪ They are also slightly curved.
STEPS TO LOCATE THE POSITION OF THE SUN:

1. Find the Month you want to find the position of the sun
for
2. Find the Time of the month you want to know the
position of the sun for
3. Find the point where the Month and Time lines intersect
4. Using that point located the altitude angle it falls on
5. Using the same point, located the azimuth angle it falls
on
Once you have located the azimuth and altitude angles you have found the exact position of the sun
from the point of view of the observer.
▪ Shading devices must be designed in order to prevent overheating due to sun’s radiation
falling on to and thus transmitting through building façade – especially the windows and walls
▪ In order to design the shading devices the following steps must be followed:
1. Locate the position of the sun at the exact time of the month where extreme heat is
found – use of hourly DBT data
2. Location of the sun during over heating must be found for every orientation the wall
is exposed to
E.g. – Find the highest average temperature in the morning (East), afternoon (south or north based
on sun path) and evening (West).
3. Find Altitude and Azimuth angles for the chosen times

4. Calculate Horizontal Shading Angle and

Vertical Shading Angle for the given time of
the month
5. Calculate the Shading Width (Vertical
Shade) and Shading depth (Horizontal
Shade)
Overheated Period can be found by using

temperature data or solar radiation data.
Focus should be on designing sun shades such
that the overheated period is taken care off
▪ This data can be found by using tabular
data or by plotting the data on the sun
path diagram
▪ Hourly data is required to find the exact
time of the month the static shading
device is to be design for – this is the
hottest period in each orientation
▪ Find the Altitude and Azimuth angles with
corresponding times
Shadow angles express the sun's position in

relation to a building face of given orientation
and can be used either to describe the
performance of (i.e. the shadow produced by) a
given device or to specify a device.
Horizontal shadow angle (HSA) is the difference in

azimuth between the sun's position and the orientation
of the building face or window considered.
HSA = AZI – ORI
▪ By convention, this is positive when the sun is

clockwise from the orientation (when AZI > ORI) and
negative when the sun is anticlockwise (when AZI < ORI).
▪ When the HSA is between +/- 90o and 270o, then the
sun is behind the facade, the facade is in shade, there is
no HSA.
▪ The horizontal shadow angle describes the
performance of a vertical shading device.

Vertical shadow angle (VSA) is measured

on a plane perpendicular to the building
face.
▪ VSA can exist only when the HSA is
between -90o and +90o, i.e. when
the sun reaches the building face
considered.
▪ When the sun is directly opposite,
i.e. when AZI = ORI (HSA = 0o), the
VSA is the same as the solar
altitude angle (VSA = ALT).
▪ Alternatively, VSA can be
considered as the angle between two planes meeting along a horizontal line on the building
face and which contains the point considered, ie. between the horizontal plane and a tilted
plane which contains the sun or the edge of the shading device
𝒕𝒂𝒏 (𝑨𝒍𝒕𝒊𝒕𝒖𝒅𝒆)
t𝒂𝒏(𝑽𝑺𝑨) = 𝑪𝒐𝒔 (𝑯𝑺𝑨)
The shadow angle protractor

▪ This is a semi-circular protractor,
showing two sets of lines (Fig.33):
▪ Radial lines, marked 0 at the center, to
-90o to the left and
▪ +90o to the right, to give readings of
the HSA
▪ Arcual lines, which coincide with the
altitude circles along the centerline,
but then deviate and converge at the
two corners of the protractor; these
will give reading of the VSA.
▪ Shading the parts of the angle
protractor where shade is possible due
to the shading devices is called the
Shadow Mask

𝑽𝒆𝒓𝒕𝒊𝒄𝒂𝒍 𝑺𝒉𝒂𝒅𝒆 (𝑺𝒉𝒂𝒅𝒆 𝑾𝒊𝒅𝒕𝒉) = 𝑾𝒊𝒏𝒅𝒐𝒘 𝑫𝒆𝒑𝒕𝒉 𝒙 tan (HSA)
𝑾𝒊𝒏𝒅𝒐𝒘 𝑯𝒆𝒊𝒈𝒉𝒕
𝑯𝒐𝒓𝒊𝒛𝒐𝒏𝒕𝒂𝒍 𝑺𝒉𝒂𝒅𝒆 (𝑺𝒉𝒂𝒅𝒆 𝑫𝒆𝒑𝒕𝒉) =
𝒕𝒂𝒏 (𝑽𝑺𝑨)

▪ Sun Shading Devices inhibit the solar radiation (block, allow, etc.) incident on a building and
are used either internally or externally or in between the internal and the external building
space.
▪ They can be any mechanical equipment (like dynamic facades), projections (chajja),
cantilevers, louvres, fins, jaalis, or even textiles.
▪ They can be fixed, manual and automatic moveable
▪ The primary objective of creating a comfortable internal environment, that is, cool in the
summer and warm in the winter.
Importance of Sun Shading Devices:

▪ Solar radiation is an important factor of thermal comfort. Sun Shading Devices improve
internal environment in order to provide greater comfort for occupants.
▪ To reduce the heat gains during summer and promote heat gain during winter, reduce the
HVAC loads and therefore minimize energy costs. Use of shading device can improve building
energy performance.
▪ To prevent glare (causing discomfort or disability of vision).
▪ To increase useful daylight availability.
▪ To create a sense of security- internal sun shading devices like curtains help to beautify
internal space and create a sense of privacy.
TYPES OF SHADES
1. Horizontal Devices: to shade a window during hot summer months, but to allow sunlight to
shine through a window in the winter, to help warm a building.
2. Vertical Devices: Primarily useful for east and west exposures to improve the insulation
value of glass in winter months by acting as a windbreak. Also radiation from the sun from
the east and west is at lower angles coming in from the sides, hence, vertical devices can
block such radiation more effectively.

3. The egg-crate: A combination of vertical and horizontal shading elements commonly used in
hot climate regions because of their high shading efficiencies. The horizontal elements control
ground glare from reflected solar rays. The device works well on walls
4. Combination or Composite shades: Based on the site’s unique position and requirements.
There can be a combination of external shades used.

GUIDE TO DESIGNING SHADES: Proper calculations for shades is a must for an effective design. Use
the shadow mask to analyze the design and find its vulnerabilities. Both internal and external
shades can be used.

These new age devices can adjust their length, width, shape and/or angle to its most ideal position
based on any set of parameters. These parameters include:
1. Tracking the movement of the sun to block normal contact
2. Shades adjust to block set level of solar radiation
3. Shades automate to bring ideal lux levels (light) indoors
4. Some shades come with solar voltaic cell – cut of direct radiation from the windows
and access the radiation to generate electricity
▪ There are several methods to design shading devices, which can be fixed or dynamic, internal
or external.
▪ Shading devices not only reduce thermal loads and energy use; they can also be an expressive
architectural design opportunity.
▪ Building performance simulation software enables the determination of cooling and heating
loads, while also providing a monthly breakdown of heating and cooling energy, for different
window sizes, orientations, and shading systems.
▪ These types of investigations can be expanded as options for parametric design and testing in
which variables can be modified automatically to determine optimum form and orientation.

Questions that must be answered:

1. Which massing and orientation options are most suitable for the climate and the program?
2. When is solar gain beneficial, and when is it a liability?
3. How much do different window-shading options reduce solar gain during the peak hour, day,
season, or month?
4. What is the optimal shape of shading systems to optimize whole building energy performance
(i.e., provide a net benefit between heating, cooling, and lighting energy while still reducing
HVAC system size)?
▪ The simulation process to design shading devices can include the following steps. The
method is not prescriptive; it is a guide in which different tools can be plugged in and out
following the described steps.
1. Climate analysis
2. Solar study
3. Shade design
4. Performance evaluation
5. Solution
Think about the following factors when using solar shading based on orientation and massing
1. When do I block or allow solar radiation?
2. What is the optimal orientation of the building or buildings?
3. What forms can provide mutual shading?
4. How to cluster buildings to provide the best option for passive solar shading?

NOTE: Use sun path diagram to aid

you with this
The following plays an impact:

1. Building(s) Shape and
Geometry
2. Height of building (s)
3. Massing (hierarchy)
4. Placement, position and
orientation
PROJECT EXAMPLE: Tooker House, Arizona State University

▪ The 458,000-square-foot Tooker
House, designed by Solomon Cordwell
Buenz (SCB), provides student housing
on the Arizona State University
campus in Tempe, Arizona.
▪ It features doubleoccupancy suites,
dining, community lounges (with
kitchens), laundry facilities, a
computer lab, and e-Space classrooms.
▪ This project focused heavily on
analyzing and evaluating solar loads.
Using incident solar radiation analysis,
multiple building forms were
evaluated for the ability to provide
solar control, self-shading potential,
and creation of outdoor spaces that
provide an oasis from the sun.
▪ This project tells the story of the
vertical louver design. When the
building form was decided, an initial
analysis informed which type of
exterior shading devices would be
beneficial on critical façades.
▪ The design team collected and
considered precedents for the vertical
louvers.

▪ The team developed a set of

vertical louver design ideas,
including the gradient louver
design shown. The incident solar
radiation analysis on the façade
without louvers set the baseline
and the basis of comparison.
▪ In addition to evaluating results
numerically, it was easy to
visually evaluate the results for
the louver design option set by
assessing the color change. The
gradient louver design was the
winner.
▪ It provides a visually dynamic skin of louvers of varying depth and angle that allows the sun to
dance along it over the course of a day, while maintaining a high degree of visual and thermal
comfort on the interior
Modelling based on accessibility of the site and the building

Accessibility can depend on a multitude of features:
▪ Location – where the site is situated
▪ Neighborhood context – the immediate surrounding of the site including data on zoning and
buildings and other impacts on our project.
▪ Zoning and size – dimensional considerations such as boundaries, easements, height
restrictions, site area, access along with any further plans.
▪ Natural physical features – actual features of the site such as trees, rocks, topography, rivers,
ponds, drainage patterns.
▪ Man made features – existing buildings, walls, surrounding vernacular, setbacks, materials,
landscaping, scale.
▪ Circulation – Vehicle and pedestrian movements in, through and around the site. Consider
the timing of these movements, and duration of heavier patterns. Future traffic and road
developments should also be considered.
▪ Utilities – Any electricity, gas, water, sewer and telephone services that are situated in or
near the site, along with distances, depths and materials.
▪ Climate – all climatic information such as rainfall, snowfall, wind directions, temperatures,
sun path, all considered during the different times of the year.
▪ Sensory – this addresses the visual, audible and tactile aspects of the site, such as views,
noise, and so on. These again should be considered in time frames and a positive or negative
factor can be attributed to the condition.
▪ Human and cultural – the cultural, psychological, behavioural and sociological aspects of the
surrounding neighbourhood. Activities and patterns, density, population ethnic patterns,
employment, income, values and so on.

Keep the following site characteristics in mind while modelling for the site:
▪ Street patterns
▪ Street section
▪ Scale and the
hierarchy/form/space
▪ Land use
▪ Typologies
▪ Neighbourhood relationships,
formal street variation
▪ Perspective relationships, views
▪ Edge conditions, surfaces and
materials
▪ Natural and man made
▪ Movement and circulation within
and around the site
▪ Vehicle vs. pedestrian
▪ Access
▪ Public space vs. private space
▪ Open space
▪ History
▪ Climate – sun angles and sun shadows
▪ Negative and positive spaces – we move through negative spaces and dwell in positive
spaces
Site and Zoning

▪ Site boundary and dimensions
▪ Any rights of way through the site and the dimensions
▪ Any easements location and dimensions
▪ Buildable area of the site
▪ Any building height restrictions
▪ Access to the site – car parking, bus routes, train stations, cycle routes, pedestrian walkways.
▪ Access to site for construction – will there be any obstacles or restrictions that could affect
the construction process?
Neighbourhood context
▪ Look at existing and proposed building uses in the neighbourhood
▪ What condition are the buildings in?
▪ Are there exterior spaces and what are they used for?
▪ Are there activities in the neighbourhood that may create strong vehicle or pedestrian
traffic?
▪ Existing vehicle movement patterns, major and minor roads, bus routes and stops.
▪ Street lighting
▪ Vernacular context, materials, architectural features, fenestration, landscaping, parking,
building heights
▪ Any nearby historical buildings, or buildings of particular significance

▪ Sun and shade patterns during the year

▪ Building context – what style, period, state of repair are the surrounding buildings? It is a
historical/heritage/conservation area? Will your design need to reflect the existing style?
▪ Is the site close to listed buildings?
▪ Surfaces and materials around the site.
Natural Features
▪ Topography of the site, valleys, ridges, slopes etc.
▪ Vegetation – landscaping, greenery, shrubs and trees, open spaces.
▪ Site levels. How will this affect your design process? How does the site drainage work, would
there be any potential problems with drainage?
▪ Soil types on site
Manmade features
▪ What was the previous use of the site? Would there be any contamination concerns?
▪ Are there existing buildings on the site – what is their state of repair? Is there any sign of
subsidence or settlement damage?
▪ Are the existing buildings part of the project?
▪ Any walls, retaining walls on the site, or other built items
Circulation
▪ Circulation – how do visitors/pedestrians/traffic
to or near the site flow around or within it.
▪ Accessibility – current provisions of disabled
access to the site and how will this need to be
considered.
▪ Does the existing pedestrian movement need to
be preserved?
▪ What is the vehicle peak loads and when?
▪ Public transport close to the site
▪ Locations of best access to site for both vehicles
and pedestrians
▪ Travel time to walk across the site
Climate
▪ Orientation of the site.
▪ Weather – how does the weather affect the site? Is it well shaded, exposed?
▪ How does the temperature, rainfall etc vary throughout the year?
▪ What are the prevailing wind directions throughout the year?
▪ What is the sun path throughout the different times of the year, and day
Utilities
▪ Location of all services: electricity, gas, water, sewer, telephone. This includes both
underground and above ground.
▪ Location of power poles.

▪ Drainage
▪ Sub-stations
Keep the following site characteristics in mind while modelling for the building:
▪ Massing
▪ Structure
▪ Circulation
▪ Axis
▪ Symmetry
▪ Scale and proportion
▪ Balance
▪ Regulating lines
▪ Light quality
▪ Rhythm and repetition
▪ Views
▪ Geometry
▪ Hierarchy
▪ Enclosure
▪ Space/void relationship
Modelling based on day lighting in all the direction with controlled heat
penetration
TWO MAJOR CONCEPTS:
Illuminance is a measure of the amount of light striking a surface. It describes the luminous flux (the
measure of perceived power of light by the human eye) incident on a surface per unit area. The SI unit
is “lux” which is the illumination by 1 lumen in 1 square meter. The foot-candle (fc), or lumen per
square foot, is also used (1 fc = 10.764 lux). Illuminance is typically used as a quantitative indicator
that compares calculated or measured values with requirements for specific activities.
Luminance is a measure of brightness of a surface, when looked at from a given direction. It refers to
the amount of light that is reflected off an object’s surface and reaches the eye. It is measured as
luminous flux density leaving a projected surface in a given direction. This means luminance is affected
by both the direction of the light source and its brightness. Luminance is measured in candelas per
square meter (cd/m2) or candelas per square feet (cd/ft2). In general, brighter luminance, larger
source size, and a more centered location in the viewing field increases the probability of experiencing
glare. However, an overall brighter average scene luminance (up to a certain level) decreases
probability of experiencing glare. There are different glare indices based on different datasets and
equations. Two of the most common ones are daylight glare probability and visual comfort probability
Daylighting models and controlled heat penetration:

▪ Daylight design should aim to achieve required illuminance levels and avoid glare.

▪ It should also control solar heat gain in the summer and reduce undesirable heat losses
through windows during colder seasons, while providing visual balance and a comfortable
environment.
▪ In fact, without detailed lighting and envelope analyses, available square footage may be
effectively reduced because of glare and thermal comfort.
▪ The intertwined nature of daylight, glare, and energy savings means that all three are
necessary to estimate the energy-related effectiveness of daylighting design.
▪ After geometry has been set up in a 3-D model, glazing properties, reflectances of interior
materials, and any shades or blinds are added. It is necessary to include these variables
because they affect the properties of daylight by reflection or transmission.
▪ Often the amount of light on a so-called work plane, 30 inches above the floor (i.e., desk
height) becomes a proxy for the amount of useful daylight within a space.
▪ More advanced simulations look at glare that a user might experience from a specific
viewpoint, for example from a desk or lying in a hospital bed.
▪ Daylight studies will typically study illuminance level on a work plane and surfaces, and glare
from selected viewpoints.
Single-point-in-time illuminance analysis

For this type of study, illuminance is measured at a specific point in time, typically equinoxes during
midmorning and midafternoon. It provides actual values at that moment.
Daylight factor (DF).

The ratio of the light level inside a building to the light level outside the building.
Daylight autonomy (DA)

This simulation indicates the percentage of occupied time when the target illuminance in a space is
met by daylight. It is indicated in an illuminance grid on the horizontal work plane.
Spatial daylight autonomy (sDA)

This simulation indicates whether a space receives enough daylight during operating hours (8 a.m. to
6 p.m.) on an annual basis using hourly illuminance grids and an algorithm to approximate manual
operation of window blinds. Grid points that achieve the target value (typically 300 lux) for at least
half of the analysis hours meet the daylighting threshold.
Annual sunlight exposure (ASE)

The intent of this simulation is to help limit excessive sunlight in a space. It measures the presence of
sunlight using annual hourly horizontal illuminance grids instead of luminance, so it is technically not
a glare metric. ASE uses 1,000 lux as the indicator for sunlight and ranges from zero to 100 percent.
Useful daylight illuminance (UDI) metric

A metric of daylight availability that corresponds to the percentage of time when a range of
illuminances are met by daylight at a specific point in a space. There are three illumination ranges: 0–
100 lux, 100–2,000 lux, and over 2,000 lux. The metric provides full credit only to values between 100
lux and 2,000 lux.

DGP calculation
These calculations detect glare sources by contrast ratios, which emphasize direct daylight and
specular reflections over dimmer surfaces. The DGP equation has the advantage of being developed
from statistical analysis of human factors assessments collected in daylight test facilities. In this scale,
a value above 0.45 is intolerable or disturbing, a value of 0.4 is perceptible, and a value below 0.35 is
imperceptible.
Visual comfort probability (VCP)

This index is defined as the percentage of people that will find a certain scene (with a given viewpoint
and direction) comfortable with regard to visual glare. According to the Illuminating Engineering
Society, it is the rating of a lighting system expressed as the percentage of people who, when viewing
from a specified location and in a specified direction, will be expected to find it acceptable in terms of
discomfort glare. Visual comfort probability is related to discomfort glare rating (DGR). Higher
numbers indicate that more people are in comfort.
For a daylighting and glare simulation, common

inputs include:
1. Climate zone
2. Type of sky
3. Window or skylight arrangement and size
4. Visual light transmittance (VLT)
5. Transmittivity or Transmittance (U-Value)
6. Light to Solar Gain Ratio (LSG)
7. Reflectivity
8. Absorptivity
9. Emissivity
10. Solar Heat Gain Coefficient (SHGC)
11. Refractive Index
12. Thickness
13. Air Tightness of window
14. Internal or external shading devices, shades or blinds
15. Use type, especially the ability of users to move their bodies or turn their heads if they
experience glare
16. Interior finish reflectance
17. Internal form of the space
DAYLIGHTING QUESTIONS TO BE KEPT IN MIND

1. Which directions produce the most solar gains?
2. How much energy can be saved by daylighting?
3. How often are the lights dimmed or off?
4. Does the client understand that daylight and glare are different, but interrelated?
5. What is the daylight balance within a space?
6. What is the optimum amount of glass (window-to-wall ratio) for daylighting?
7. How many/how large should skylights be for adequate daylighting?
8. What is the difference between automated and manual blinds?

9. How can the building architecture be designed to help encourage occupants to be more active
around interior blinds management, thus improving overall daylighting?
10. For interior window treatment, do blinds or shades perform better?
11. What is the reduction in annual daylight based on external shading systems?
GLARE QUESTIONS TO BE KEPT IN MIND

1. What are key locations where glare should be evaluated?
2. Are there particular times of day when glare should be considered?
3. Are blinds being deployed manually or as part of a controls system?
4. If interior surface reflectances are brighter, how does this affect visual comfort?
5. How does a light shelf impact the distribution of daylight and glare in a space?
PROJECT EXAMPLE: Louisville Free Public Library

▪ The Louisville Free Public Library in Louisville, Kentucky, designed by MSR, is a space intended
to promote learning at all stages and serves more than 160,000 people. L
▪ Located in climate zone 4, the 40,000-square-foot library has an energy profile dominated by
cooling load.
▪ A daylighting analysis was developed to evaluate the performance of a set of building forms
and glazing options for a set of daylighting metrics, loads, and energy use intensity.
▪ The building forms were modeled in SketchUp. Sefaira was used to analyze energy.
▪ The models were brought into Rhino, so that the DIVA plug-in could be utilized for the
daylighting analysis. Combining these metrics into a single graphic clearly and convincingly
establishes connections between the influence of the building form and glazing design on
daylighting and overall energy. This methodology for integrating and visualizing early design
analysis has since become standard practice at the firm.

Modelling based on air movement, impact of air through the site-specific

wind direction
Natural ventilation consists of using natural forces (e.g., buoyancy and wind) to drive air through a
space. This air can be used to provide:
• The right amount of fresh air to meet the space’s ventilation (indoor air quality/IAQ)
requirements
• The right amount of cool air to meet the space’s cooling demand (also known as “ventilative
cooling”)
▪ Because the amount of outdoor air needed to cool a space is often greater than that needed
to maintain acceptable indoor air quality, we tend to think of natural ventilation as a cooling
strategy only.
▪ However, keep in mind that natural ventilation can also be used in the wintertime to
maintain adequate indoor air quality (a strategy often known as “trickle ventilation”) while
using mechanical heating to maintain thermal comfort conditions.
▪ Natural ventilation is essentially an engineered HVAC (or at least VAC) system. Despite the
challenges this system presents in building performance simulation, it can be used to very
effectively reduce energy use and introduce more natural conditions into an indoor space
1. Simulating natural ventilation concerns three main variables:
2. Airflow through a space (important for IAQ)
3. Indoor temperature in that space (important for thermal comfort)

4. Air speed at the window (important to determine whether the air speed may lead
to, for example, papers flying off desks)
Computational fluid dynamics (CFD)

▪ This approach simulates the movement and
temperature of air within or outside buildings, and
may be used to evaluate the effectiveness of
natural ventilation for a specific point in time.
▪ Outdoor CFD simulations are run to evaluate the
impact of wind and surroundings on façade
pressures. I
▪ Indoor CFD simulations are used to understand the
flow, temperature distribution, and pressure
losses within a building but are not ideal for
simulating thermal mass effects because of the
associated computational requirement.
▪ For the sake of accuracy, indoor and outdoor simulations should be run separately, and only
to answer questions that other simulation tools cannot.
▪ Architects should ensure that the building performance simulation professional they work
with to simulate natural ventilation understands this.
Factors that will influence the size of the NV openings:

1. Thermal comfort assumptions (if occupants will have control over their clothing levels
and some operable windows, an adaptive comfort range per ASHRAE Standard 55 may
be assumed)
2. Placement of windows, internal partitions, internal shafts Window types and
dimensions (for spaces ventilated with single-sided ventilation)
3. Building orientation, solar and
internal gains
4. Flow obstructions (windows
with insect screens should be
about 30 percent larger than
windows without them)
5. Amount of exposed thermal
mass
6. Use of fan assist
7. Use of ceiling fans
Factors that will affect the energy savings associated with using NV:
1. System design
2. Climate zone (outdoor temperature, humidity, wind direction and speed)
3. Window controls (manual vs. automated)
4. Night flushing controls (if any)

WIND FLOW AND DIRECTION:

▪ The greatest pressure on the windward side
of a building is generated when the
elevation is at right angles to the wind
direction, so it seems to be obvious that the
greatest indoor air velocity will be achieved
in this case.
▪ A wind incidence of 45° would reduce the
pressure by 50%. Thus the designer must
ascertain the prevailing wind direction from
wind frequency charts of wind roses 6 and
must orientate his building in such a way
that the largest openings are facing the
wind direction.
▪ It has, however, been found by Givoni that a
wind incidence at 45° would increase the
average indoor air velocity and would provide
a better distribution of indoor air movement
▪ Option A in the figure, shows the outline of air

flow at 90° and Option B at 45°, to a building
square in plan. In the second case a greater
velocity is created along the windward faces,
therefore the wind shadow will be much
broader, the negative pressure (the suction
effect) will be increased and an increased
indoor air flow will result.

Wind flow can change based on building height, shape, position etc. This flow can then be used to
serve the needs to create an artificially induced ventilation non-mechanically:

INDUCTION VENTILATION: WINDOW TOWER
VENTILATION SYSTSEMS THROUGH PASSIVE MEANS:

Questions to be answered for CFD Natural Ventilation Simulation:

1. Which thermal comfort criteria should be used for a certain building typology? Can adaptive
comfort be used? (see ASHRAE Standard 55)
2. Will the building use ceiling fans to expand the thermal comfort band?
3. Based on indoor comfort assumptions, which outdoor air temperature and humidity ranges
are acceptable for natural ventilation?
4. What size should windows and interior transfers be? How is this impacted by the use of
insect screens? How many windows are needed?
5. How will natural ventilation perform in the absence of wind? How will it perform in the
presence of unfavorable winds?
6. How many hours of the year is natural ventilation expected to be in use?
7. How much cooling and fan energy does natural ventilation save?
8. Should the building rely on manual or automatic controls? If manual, what is the best way to
provide feedback to users regarding ideal times to open windows?
9. What are the optimal night flush schedules and control settings that optimize energy
savings?
10. Will NV and AC be allowed to operate concurrently in the same floor or building? If so, how
will NV be integrated with HVAC controls?
Analyze the sizing of the natural ventilation system within the overall system for key variables
such as:
▪ Direction of the flow to confirm that the minimum ventilation rate for the desired level of
indoor air quality is being met
▪ Amount of airflow through a zone to confirm that the calculated flowrate is indeed flowing
from the outdoors into a zone, rather than backflowing from other occupied zones
▪ Air speed at the inlet to assess whether there is any risk of high-speed drafts in the space
▪ Temperature difference between the air entering a zone and that exiting the zone as a direct
indicator of when natural ventilation can be used throughout the year
Results used to quantify energy savings associated with natural ventilation should clearly indicate:
▪ The thermal comfort model (adaptive or traditional) assumed to decide when the windows
can be open
▪ The control algorithm assumed for window operation (including minimum/maximum
outdoor/indoor temperatures, and any periods during which windows are not expected to be
open, such as pollen season and nighttime)
▪ The control algorithm assumed for HVAC operation in conjunction with natural ventilation
▪ The times of the year when natural ventilation can be used (and how much of that time falls
during occupied/unoccupied hours)
Evaluation and assessment based on Building type/ function and program

BUILDING TYPE, FUNCTION AND PROGRAM CAN IMPACT:
▪ Number of occupants in the buildings
▪ Usage of mechanical equipment/HVAC/Lighting etc
▪ Usage pattern of equipment/appliances

▪ Activities of the occupants in the building

▪ Duration of activities/usage of equipment/appliances
▪ Internal gain of the building
▪ Energy Consumption
▪ Area, height and volume of the building
▪ Its association thermal gain/thermal comfort levels/visual comfort levels
▪ Natural Ventilation vs HVAC
▪ Lighting levels
▪ Different building types will have to meet different minimum standards.

▪ According to ECBC even the U-value of the construction vary with building types
▪ Different LPD and Lighting levels are maintained based on typology and/or activities to occur
within the building
▪ Even buildings which have the same area but are of different building typology, the energy
consumption will vary

Generating Building performance with respect to microclimate, urban

planning, envelope design, material specification
Architects make many decisions that affect the lifetime energy use of a building. These include a
building’s relationship to site and microclimate, its orientation, massing, envelope and glazing
materials, lighting and daylighting, and programming.
BUILDING PEFORMANCE - MICRO-CLIMATE AND URBAN DESIGN

▪ Micro-climates may occur in parcels of lands whose climatic phenomena may be different
from that its wider area.
▪ This may be due to several factors – canopy cover, induction of wind due to certain
characteristics, local water bodies etc.
▪ In an urban environment the micro-climate may be caused due to urban planning, density,
material usage, wind breakers, shading by tall buildings etc
▪ Complex urban areas with wide variations in built density, layout typology, and architectural
form have resulted in more complicated microclimate conditions.
▪ Microclimate conditions affect the energy performance of buildings and bioclimatic design
strategies as well as a high number of engineering applications.
▪ The Urban Heat Island (UHI) is an area specific phenomena where the temperature of one
area is higher than that of the surrounding areas.
▪ This is caused by area of buildings and roads, reduction of green cover and materials that
absorb and retain heat.

▪ Micro-climate temperatures increase due these factors can increase the temperature by 1-
12 degrees.
▪ Temperature difference is larger at night than in daytime – escape of radiation to night sky
reduced, stagnation of heat
▪ Rise in temperature creates higher demand for air conditioning

▪ Demand for electrical power rises nearly 2% for every degree Fahrenheit the daily max
temperature rises.
▪ Increase in temperature – decrease in pedestrian and bicycle riding – increase in pollutants
and heat emissions – need for more roads
▪ Decreased and more comfortable micro-climate can lead to decreased energy use
▪ Certain conditions of the urban environment (especially tall buildings) can create long and
large shadows – cutting of smaller buildings access to sunlight and decreased daylight
▪ This creates increased use of artificial lighting systems even during daytime
▪ The form, geometry and material properties of certain features can induce strange micro-
climatic conditions
▪ For example – the infamous walkie talkie buildings curved shape and use of glazing created
unusually high temperatures – a car caught on fire due to this! Surrounding area had to face
high temperatures and increased glare.
▪ Certain buildings induced increased wind speeds that people literally have to hold on to
railings to be kept from being swept away

ENVELOPE DESIGN AND MATERIAL SPECIFICATION
▪ The building envelope is the physical barrier between the exterior and interior environments
enclosing a structure.
▪ Generally, the building envelope is comprised of a series of components and systems that
protect the interior space from the effects of the environment like precipitation, wind,
temperature, humidity, and ultraviolet radiation.
▪ The internal environment is comprised of the occupants, furnishings, building materials,
lighting, machinery, equipment, and the HVAC (heating, ventilation and air conditioning)
system

1. Structural: If the wall is not part of the main building structure, support own weight and
transfer lateral loads to building frame.
2. Water: Resist water penetration.
3. Air: Resist excessive air infiltration.
4. Condensation: Resist condensation on interior surfaces under service conditions.
5. Movement: Accommodate differential movement (caused by moisture, seasonal or diurnal
temperature variations, and structural movement).
6. Energy conservation: Resist thermal transfer through radiation, convection and conduction.
7. Sound: Attenuate sound transmission.
8. Fire safety: Provide rated resistance to heat and smoke.
9. Security: Protect occupants from outside threats.
10. Maintainability: Allow access to components for maintenance, restoration and replacement.
11. Constructability: Provide adequate clearances, alignments and sequencing to allow
integration of many components during construction using available components and
attainable workmanship.
12. Durability: Provide functional and aesthetic characteristics for a long time.
13. Aesthetics: Do all of the above and look attractive.
14. Economy: Do all of the above inexpensively.
Performance refers to the desired level (or standard) to which the system must
be designed for each of the above functional requirements.

Simulation of heat and mass transfer phenomena through building

components and materials
HEAT: form of energy, contained in substances as molecular motion or appearing as electromagnetic
radiation in space. Energy is the ability or capacity for doing work and it is measured in the Joules.
Unit: Joules (J)
Energy is transported by CONDUCTION as molecules vibrate, rotate and/or collide into each other.
Heat is moved along similar to dominos knocking down their neighbors in a chain reaction.

An increase of ELECTROMAGNETIC RADIATION into a system causes the molecules to vibrate, rotate
and/or move faster.
With CONVECTION, higher energy molecules are mixed with lower energy molecules. When higher
energy molecules are mixed with lower energy molecules the molecular motion will come into
equilibrium over time.

HEAT FLOW RATE:

▪ Rate of heat flow is measured in Watts
▪ Power is the ability to do work in unit time. It is
the rate of energy expenditure
UNIT: J/s or Watt
SPECIFIC HEAT: provides the connection between heat and temperature. This is the quantity of heat
required to elevate the temperature of unit mass of a substance by one degree. This is a material
property.
UNIT: J/kg °C or J/kg.K
Its magnitude is different for different materials and it varies between:
a) 100 and 800J/kg.K for metals
b) 800 and 1200J/kg.K for masonry materials (brick, concrete)
c) Water, which has the highest value of all common substances: 4176J/kg.K

CONDUCTIVITY (W/m.K), DENSITY (kg/m3) and SPECIFIC HEAT (J/kg.K) values for building
materials.
THERMAL CAPACITY: of a body is the product of its mass and the specific heat of its material. It is
measured as the amount of heat required to cause unit temperature increase of the object (note: not
material – that is specific heat capacity).
From these definitions, we can see that thermal capacity is an extensive property. This means that it
varies per amount of the substance. For example, 50 grams of iron will have a different thermal
capacity as 100 grams of the same substance. Meanwhile, specific heat capacity is an intensive
property. Using the same example, 50 grams of iron will have the same specific heat as 100 grams of
iron.
UNIT: J/ °C or J/K
For example, imagine the above represents a certain material of mass 8kg. The 1kg highlighted will be
the specific heat capacity of the material (specific heat capacity is a material property) but the thermal
capacity will tell you how much total energy is required to raise all of the 8kg by a degree temperature
difference. Hence, 8 times the specific heat capacity will give you the thermal capacity.
Heat exchange processes between a building and the external environment:

▪ Heat flows by conduction through various building elements such as walls, roof, ceiling, floor,
etc.
▪ Heat transfer also takes place from different surfaces by convection and radiation.
▪ Convection can occur within the building through the movement of wind or ventilation.
▪ Besides, solar radiation is transmitted through transparent windows and is absorbed by the
internal surfaces of the building.
▪ There may be evaporation of water – resulting in a cooling effect.
▪ Heat is also added to the space due to the presence of human occupants and the use of lights
and equipment.
Thermal performance of a building depends on a large number of factors. They can be summarized
as:
(i) Design variables - geometrical dimensions of building elements such as walls, roof and windows,
orientation, shading devices, etc.

(ii) Material properties - density, specific heat, thermal conductivity, transmissivity, etc.
(iii) Weather data - solar radiation, ambient temperature, wind speed, humidity, etc.
(iv) Building’s usage data - internal gains due to occupants, lighting and equipment, air exchanges,
etc.
THERMAL CONDUCTIVITY (k-Value):

A measure of the ability of a material to transfer heat. Given two surfaces on either side of a material
with a temperature difference between them, the thermal conductivity is the heat energy
transferred per unit time and per unit surface area of unit thickness, divided by the temperature
difference
Or in other words:
It is the time rate of steady state heat flow through a unit area of a unit thickness of a homogeneous
material induced by a unit temperature gradient in a direction perpendicular to that unit area.
Lower the conductivity, the better the insulator a material is
Unit: W/m°C or W/mK
THERMAL RESISTIVITY:
The quantity determined by the temperature difference, at steady state, between two defined
surfaces of a material or construction that induces a unit heat flow through a unit area. This is a
material property.
Or in other words
It is simply the reciprocal of the conductivity value.

Resistivity = 1/k
Better insulators will have higher resistivity values.
Unit: m°C/W or mK/W
THERMAL RESISTANCE (R-VALUE):

Resistance of a body (may comprise of different materials of varying thickness) is the product of its
thickness and the resistivity of each of its material.
R = b x (1/k) = b/k (formula for one material with thickness)
Unit: m2 °C/W or m2K/W
THERMAL CONDUCTANCE (C-VALUE):

This is the heat flow rate through a unit area of the body when the temperature difference between
the two surfaces is 1 degree C.
C = 1/R
Unit: W/m2 °C or W/m2K
THERMAL CONDUCTANCE (C-VALUE):

Conductance is a heat flow through a unit area
of the body (i.e. density of heat flow rate)
when the temperature difference between the
two surfaces is 1 degree K or °C.
Or in other words:
It is the time rate of steady state heat flow
through a unit area of a material or
construction induced by a unit temperature
difference between the body surfaces.
Unit: W/m2 °C or W/m2K
MULTILAYER BODY:
The resistance of a multi-layer body of different
materials will be the sum of resistances of
individual layers
The conductance (C) can be found by finding its
total resistance (R) and takings its reciprocal.
Rbody or Rb = R1 + R2 + R3
= (b1/k1) + (b2/k2) + (b3/k3)
= Σ (b/k)
C = (1/Rbody)

SURFACE CONDUCTANCE AND RESISTANCE:

Along with the body, the surface of a material offers a
resistance as well, where a thin film of air separates the body
from the surrounding air: Surface or thin film resistance.
Surface conductance is taken to be ‘f’ , so surface resistance
will be taken as 1/f.
Units for Surface Conductance: W/m2 °C
Units for Surface Resistance: m2 °C /W
The surface conductance may also be represented with the
symbol ‘h’, which is the sum of convective (hc) and radiative
components (hr).
Surface resistance may be represented as Rs
SURFACE RESISTANCE VALUES – RSI AND RSO :
RSI = Surface Resistance Inside/Internal
RSO or RSE = Surface Resistance outside/External

AIR CAVITIES:
If an air space or cavity is enclosed within a body, through which the heat transfer is considered, this
will offer another barrier to the passage of heat.
It is measured as the cavity resistance (Rc) which needs to be added along with the other resistances
to find the overall air-to-air resistance (R) of the body’s resistance.
AIR-TO-AIR RESISTANCE:
If the heat flows from air on one side of the body, through the body and then to the other side of the
body, the overall resistance must be calculated.
Overall air-to-air resistance of a body (Ra-a) is the sum of the surface resistances (RSI and Rso) , body
resistance (Rb) and any cavity resistances (Rc) if present.
AIR-TO-AIR TRANSMITTANCE (U-VALUE):
▪ U-Value is the heat transmission in unit time through unit area of a material construction and
the boundary air films, induced by unit temperature difference between the environments on
each side.
▪ U-Value measures the heat loss in a building element such as a wall, floor or roof.
▪ It can also be referred to as an overall heat transfer coefficient and measures how well parts
of a building transfer heat.
▪ This means that higher U-value means less insulation – resulting in bad thermal performance
of the building envelope. A low U-value indicates high level of insulation.

AIR-TO-AIR TRANSMITTANCE (U-VALUE):
U-Value is defined as being the reciprocal of all the resistances of the materials found in the building
element.
Periodic Heat Flow:

▪ In nature the variation of climatic conditions
produces a non- steady state. Diurnal
variations produce an approximately
repetitive 24-hour cycle of increasing and
decreasing temperatures.
▪ The effect of this on a building is that in the
hot period heat flows from the outdoors into
the building, where some of it is stored, and at
night during the cool period the heat flow is
reversed: from the building to the outside.
▪ As this cycle is repetitive, it is described as
periodic heat flow.
▪ The diurnal variations of external and internal
temperatures are a periodic cycle.
Periodic Heat Flow:

▪ In the morning, as the outdoor temperature increases, heat starts entering the outer surface
of the wall.

▪ Each particle in the wall will absorb a

certain amount of heat for every degree
rise in temperature, depending on the
specific heat of the wall material.
▪ Heat to the next particle will only be
transmitted after the temperature of the
first particle is increased.
▪ Thus the corresponding increase in the
internal temperature will be delayed.
▪ The outdoor temperature reaches its peak
and starts decreasing, before the inner
surface temperature has reached the same level.
▪ From this moment the heat stored in the wall will be dissipated partly to the outside and only
partly to the inside.
▪ As the out door air cools, an increasing proportion of this stored heat flows outwards, and
when the wall temperature falls below the indoor temperature the direction of the heat flow
is completely reversed.
THERMAL MASS:
▪ Thermal mass refers to the material inside a building that can help reduce the temperature
fluctuations throughout the course of the day; thus reducing the heating and cooling demand
of the building itself.
▪ Thermal mass materials achieve this effect by absorbing heat during periods of high solar
insolation, and releasing heat when the surrounding air begins to cool. When incorporated
into passive solar heating and cooling technologies, thermal mass can play a large role in
reducing a buildings energy use.
An ideal material for thermal mass will have:
1. High heat capacity
2. High material density

Time Lag and Decrement Factor:

▪ The time delay due to the thermal mass is known as a time lag.
▪ The thicker and more resistive the material, the longer it will take for heat waves to pass
through.
▪ The reduction in cyclical temperature on the inside surface compared to the outside surface
is knows and the decrement.
▪ Thus, a material with a decrement value of 0.5 which experiences a 20 degree diurnal variation
in external surface temperature would experience only a 10 degree variation in internal
surface temperature.
Solve this Problem:

What is the time lag and decrement factor in the graph to the top of this slide? Assume Timax
= 20 and Tomax = 30
Solution:
Time lag = Peak Hour at Timax (Interior Temp.) - Peak Hour at Tomax (Outdoor temp.)
= 24 – 15
= 9 hours
Decrement factor = Timax / Tomax = 20/30 = approx. 0.67
▪ This effect is particularly important in the design of buildings in environments with a high
diurnal range.
▪ In some deserts, for example, the daytime temperature can reach well over 40 degrees. The
following night, however, temperatures can fall to below freezing.
▪ If materials with a thermal lag of 10-12 hours are carefully used, then the low night-time
temperatures will reach the internal surfaces around the middle of the day, cooling the
inside air down.
▪ Similarly, the high daytime temperatures will reach the internal surfaces late in the evening,
heating the inside up.
▪ In climates that are constantly hot or constantly cold, the thermal mass effect can actually
be detrimental. This is because both surfaces will tend towards the average daily temperature
which, if it is above or below the comfortable range, will result in even more occupant
discomfort due to unwanted mean radiant gains or losses.

▪ Thus in warm tropical and equatorial climates, buildings tend to be very open and
lightweight. In very cold and sub-polar regions, buildings are usually highly insulated with
very little exposed thermal mass, even if it is used for structural reasons.
Sol-Air Temperature:
▪ For building design purposes, it is useful to combine the heating effect of radiation incident
on a building with the effect of warm air: sol-air temperature concept
▪ A temperature value is found which would create the same thermal effect as the incident
radiation in question and this value is added to air temperature
Clarification:
▪ Rsi = 1/hi and Rso = 1/ho
▪ Rsi = Outside Surface Resistance
▪ Rso = Inside Suraface Resistance
▪ hi = Inside heat transfer coefficient (also known as inside surface conductance)
▪ ho = Outside heat transfer coefficient (also known as outside surface conductance)
▪ NOTE: Check slide no. 22 to recap on surface resistances. This was used to calculate air-to-
air resistance (see slide 25).

Solar Heat Gain Factor:
▪ To consider the combined effects

of reflective surfaces and thermal
insulation
▪ To reduce heat gain, a dark,
highly absorptive surface with
good insulation may be just as
effective as a more reflective but
less well-insulated element.
▪ It is the heat flow rate through
the construction due to solar
radiation expressed as a fraction
of the incident solar radiation
▪ Value should not exceed 0.04 in warm humid climate and 0.03 in hot dry part of composite
climate when ventilation is reduced.
𝑸 axU
=
ST ℎ𝑜
Material Quality in Envelope:

The material qualities we have already discussed:
1. Specific Heat (material property) Thermal Capacity (object property)
2. Thermal Conductivity (material property), Thermal conductance (Object property)
3. Thermal Resistivity (material property), Thermal Resistance (object property)
4. U-Value (Object Property)
More important material properties that an architect must be familiar with to design climate
responsive buildings:
1. Density - Densities of construction material are its mass per unit volume of material. It is
expressed in kg/m3 and shows compactness of building material. Density is also called as
unit weight of substance. It is represented by symbol called row (p).
p = m/v = mass/volume
Units = kg/m3
2. Color and texture - define surface characteristics such as emissivity, reflectivity, absorptivity and
roughness. These are vital for heat flow and light distribution. For example, if the roof of a building is
painted white, then the transmission of heat can be reduced by upto 80% as compared to a dark
color.
3. Opaque and Transparent - Generally, the building components can be categorized into opaque
and transparent elements. For example, a brick wall is an opaque element whereas a glazed window
is a transparent element. Transparent elements allow direct solar radiation into the living spaces.

Unlike thermal conduction or convection, radiative

heat transfer (heat transfer by radiation) requires no
medium to transfer heat.
When thermal radiation falls onto an object, some
combination of 3 things will happen.
1. The radiation will be absorbed by the surface of
the object, causing its temperature to change.
2. The radiation will be reflected from the surface of
the body, causing no temperature change.
3. The radiation will pass completely through the
object, causing no temperature change
Note: A building can be incident to short wave
radiation (direct electromagnetic radiation from the
sun) and long wave radiation (The ground and other
objects heat up and re-emits energy in long wave
radiation).
4. Absorptivity (α): The fraction of irradiation absorbed by the surface is called the absorptivity (α).
It is the ratio of absorbed radiation (G abs) to incident radiation (G).
Its value: 0 ≤ α ≤ 1
5. Reflectivity (ρ): The fraction of radiation reflected by the surface is called the reflectivity (ρ). It is
the ratio of reflected radiation (G ref) to incident radiation (G).
Its value: 0 ≤ ρ ≤ 1
6. Transmissivity (τ): The fraction of radiation transmitted is called the transmissivity (τ). It is the
ratio of transmitted radiation (G tr) to incident radiation (G).
Its value: 0 ≤ τ ≤ 1
α+ρ+τ=1
7. Emissivity (ε) is a measure of how much
thermal radiation a body emits to its environment.
It is the ratio of the radiation emitted from its
surface to the theoretical emissions of an ideal
black body of the same size and shape. This
parameter thus defines radiative heat transfer
away from a given object. Since it is a ratio of
identical parameters, it is unitless, and will range
between 0 and 1.

8. Solar Heat Gain Coefficient (only used for

transparent surfaces like window): is the fraction
of incident solar radiation admitted through a
window, both directly transmitted and absorbed
and subsequently released inward. SHGC is
expressed as a number between 0 and 1. The
lower a window's solar heat gain coefficient, the
less solar heat it transmits.
NOTE: A U-Value is the measure of how much

heat energy is transferred through a body. Heat
can be lost and gained through a window by the
processes of conduction, convection and radiation. The lower the u-value, the better the window
reduces heat transfer.
Solar Heat Gain Coefficient (SHGC) is the measure of the percentage of solar heat gain that passes
through a window. Reflection, absorption and transmittance are factors that affect the SHGC.
9. Visual Light Transmission – VLT (Windows only): amount of light in the visible portion of the
spectrum that passes through a glazing material. VLT is expressed as a number between 0 and 1.
10. Light to Solar Gain Ratio (Windows Only): The ratio of the VLT to the SHGC
LSG = VLT/SHGC
A higher selectivity means sunlight entering the room is more efficient for daylighting, especially for
summer conditions where more light is desired with less solar gain. This ratio is the measurement
used to determine whether the glazing is “spectrally selective.”

CALCULATING HEAT TRANSFER:
For all the surfaces of a building one must add the heat gain or loss:
Q =Q +Q +Q +Q +
total conduction convection radiation-walls solar heat gain Qinternal
CONDUCTION:

COVECTION:
RADIATION – OPAQUE SURFACES:
Sky temperature is difficult to calculate, hence, the formula below is usually used for
calculations:
NOTE: hr is the radiative heat transfer coefficient, and ∆R is the difference between the long
wavelength radiation incident on the surface from the sky and the surroundings, and the radiation
emitted by a black body at ambient temperature. For horizontal surface, ∆R can be taken as 63 W/m2
and for a vertical surface, it is zero
RADIATION – TRANSPARENT SURFACES or Solar Heat Gain (Qsg)

For unshaded windows the Solar heat gain is:
For shaded windows the Solar heat gain is:

Internal Heat Gain
The heat generated by occupants is a heat gain for the

building; its magnitude depends on the level of activity
of a person. The heat gain due to appliances (televisions,
radios, etc.) should also be added to the Qi.
Qi = (No. of people X heat output rate) + Wattage of

lamp (1-Leff) + Appliance load (1-Aeff)
Leff = Lamps efficiency. Value is between 0-1.

Higher values mean more efficiency and less heat
output
Aeff = Appliance efficiency. Value is between 0-1.
Higher values mean more efficiency and less heat
output
SIMPLIFIED METHOD FOR PERFORMANCE ESTIMATION:

In order to find the cooling load calculations of a room/building, we need to first find the Heat Balance
or Qtotal. Under the steady state approach (which does not account the effect of heat capacity of
building materials), the heat balance for room air can be written as:

STEADY STATE APPROACH

You may have noticed that calculating the heat transfer or the heat balance Qtotal from the slides above
is tedious and many values may not be at your disposal to calculate. Also, values usually change are
and are dynamic (eg. Outside temperature)
Hence, simplified method for performance estimation is performed to get a quick estimation.
CONDUCTION:
NOTE: We are taking into consideration the radiation on the wall by using Sol-Air
temperature instead of the outdoor temperature.
∆R = 0 for vertical surfaces (e.g walls)

2
∆R = 63 W/ m for Horizontal Roofs
VENTILATION:

SOLAR HEAT GAIN:
NOTE: Radiation effects on the wall (opaque) has already been taken account in
Conduction by taking the Sol-Air Temperature instead of the Outside air Temperature.
INTERNAL HEAT GAIN:
The heat generated by occupants is a heat gain for the building; its magnitude depends on the level
of activity of a person. The heat gain due to appliances (televisions, radios, etc.) should also be added
to the Qi.
Qi = (No. of people X heat output rate) + Wattage of lamp (1-Leff) + Appliance load (1-Aeff

No difference from the calculation stated previously
SIMULATION OF HEAT AND MASS TRANSFER:
▪ Building performance simulation to optimize energy performance can actually be thought of

as two simulations—a load model and an energy model— reflecting an iterative process or
“balancing act” between thermal loads and the response of the building to those loads.
▪ Load modeling simulates heating and cooling loads: It sums the heat gains (e.g., people,
electric lighting, and solar gain) and subtracts the heat losses (primarily conduction through
the envelope on cold days) from each space.
▪ After thermal loads are calculated, an energy model calculates how the HVAC system
responds to these loads to maintain thermal comfort.
▪ Note that “peak” thermal loads are calculated for a single day to determine the size of the
mechanical system; thermal loads are also calculated at each hour to simulate how the HVAC
system will respond as part of an energy model. There are two primary sources of thermal
loads: external and internal.
▪ External loads come from the outdoor environment. Cold and warm weather as well as
sunshine create loads through the building envelope. Location-specific weather information,
including air temperature, humidity, wind, precipitation, and, critically, solar radiation, is
found in “weather files,” which all building performance simulation software needs and reads.
▪ Internal loads come from the inside the building. Lights, electronics, elevators, refrigerators,
cooktops, washing machines, and other equipment all produce waste heat, as do people.
QUESTIONS TO BE ASKED DURING THE DESIGN STAGE:
Peak loads and energy use

1. What is the total energy
use on an annual/
monthly/daily basis?
Peak loads and envelope design
1. How much does each
envelope component
contribute to peak loads,
annual loads, and energy
use?
2. What is the optimal
amount of insulation in the
walls?
3. How much can the mechanical system be downsized by installing more insulation, fewer
windows, or less glazing?
4. What are the ideal performance properties for the windows?
5. How much is comfort affected by an improved wall U value? Peak loads and mechanical
system design

6. What are the peak loads and rough mechanical costs?

7. How much money can I save by reducing mechanical system size through load reduction
measures?
8. When are the peak loads occurring and how do I reduce them?
9. Which zones are driving peak cooling and peak heating loads?

UNIT 3: MODELLING FOR ACTIVE SYSTEMS

UNDERSTANDING BUILDING PERFORMANCE BENCHMARKS
The sustainability performance of a building can be viewed from two basic perspectives, and we
have used two simple terms to describe them:
Design
▪ The sustainability performance which the physical fabric and components of the building has
been designed to achieve, e.g., the performance specification of the insulation, heating and
cooling systems, or lighting systems.
▪ Refurbishment or significant maintenance programmes present opportunities for the owner
to improve systems such as heating/cooling or lighting and upgrade the sustainability
performance of the physical fabric of the building and its plant.
In-use
▪ The measured operational sustainability performance of the building when it is in use by
occupiers.
▪ Operational performance is affected by both how occupiers utilise a building and how the
owner runs shared services. The interface between the two parties is important in
determining how efficiently the overall building is operated.

The benefits of sustainability benchmarking Sustainability benchmarking of a property or property

portfolio brings a number of benefits to its users, as it:
1. Enables an organization to assess its impact on the environment at both an individual

building and portfolio level - This may be in terms of CO2 emissions, fuel consumption, waste
generation or water consumption, etc., of individual buildings or portfolios, and can be
reported in absolute and/or normalised terms.
2. Facilitates a greater understanding of how a portfolio is operating - The benchmarking

process will identify high impact and low impact buildings, leading to a greater understanding
of why certain buildings may consume more than others. For example, a highly intensive
building within a portfolio may simply house energy intensive activities, such as a server
room. The key question is whether the building is performing optimally.
3. Identifies where action is appropriate and where greatest savings can be made - A greater
understanding of the sustainability profile of a building or portfolio will highlight poor-
performing and well-performing buildings, identifying the areas where action is required and
where the greatest improvements/cost-savings can be made.
4. Enables an organisation to set and monitor realistic targets - Once an organisation

understands how a specific building or portfolio is operating, appropriate targets can be set
and the performance against these targets monitored. Sustainability benchmarking will also
identify where performance improvement programmes have been successful and what
changes have been achieved, thereby helping plan the most appropriate allocation of
resources for improvements.
5. Enables for the comparison of buildings and portfolios between peer groups - Commercial
property owners will be able to compare assets within their portfolios, well as against other
owner’s properties/portfolios. Sustainability benchmarking would also enable fund manager
or potential investors to compare across funds or property portfolios.
6. Assists legislative and regulatory compliance – Benchmarking also creates a robust

framework that can help facilitate preparation for compliance with emerging legislation.
7. Helps improve asset value - There seems to be an increasing trend among investors to take
sustainability factors into account in their decision- making processes. Furthermore, the
increasing volume of legislation and mandatory standards for the environmental
performance of buildings, as well as occupiers’ rising aspirations for greener buildings, would
seem to indicate that green factors will play a greater role in the way buildings are valued in
years to come. Sustainability benchmarking should therefore assist valuation as well as
investment processes and decision-making in the future.

Stages in developing a benchmark

UNEP Sustainable Buildings & Climate Initiative (SBCI) – proposed sustainability indicators

Issues and Challenges in Operational Sustainability Benchmarking
1 . Data collection
▪ Collecting accurate, consistently measured and verifiable data is the first step to develop an
appropriate and robust benchmarking process that will enable performance and progress to
be measured, monitored and managed and, most importantly, help focus behavioral changes
to achieve the best results in terms of sustainability performance.
▪ Unfortunately, a lack of data may lead to situations whereby it is not possible to employ the
most effective. However, organizations can start by using available data, however limited it
may be, and increase and improve the sophistication and robustness of the process over
time.
▪ It is important, at the outset, to clearly define the scope and purpose of the benchmarking
exercise and the intended areas for incentivizing behavior. Following this, organizations
should carefully consider the indicators they wish to report (e.g., annual kgCO2 per m2) and
accordingly identify the type of metrics and associated data that needs to be collected.
2. Measuring performance
A number of critical aspects must be accounted for when measuring performance. The operational
performance of a building can be represented in both absolute and normalised terms.
▪ A. Absolute Performance - Absolute performance can be an important means of

understanding the overall impact of a portfolio/organisation, e.g., total CO2 emissions per
year or comparing a consistent portfolio over time. The main concern with absolute measures
of performance is that care has to be taken to take account for the dynamic nature
▪ B. Normalised Performance - Normalised indicators take into account the dynamic nature of
the real estate market and allow comparisons of portfolios and buildings’ performance over
time. Normalisation is achieved by relating the impact of a performance metric (e.g., CO2 ,
or litres of water) to another driving variable, such as floor area or density of occupation of a
building. For example, emissions could be presented for an office building in terms of CO2
per m2 , or CO2 per full time equivalent employee (FTE) or per workplaces. Deciding which
normalisation metric to use for assessing sustainability performance and developing
benchmarking tools can be challenging, as the results ultimately can have an influence on the
appropriate behaviour to improve building performance.
▪ Comparing and benchmarking performance - In order to compare performance across

properties on a like for like basis, buildings need to be categorized into similar peer groups
and special uses should be considered.
▪ Categorization of building – In defining the parameters for benchmarking, it is fundamental

to establish categories of buildings in order to enable comparison between assets of similar
characterstics

ANALYSING OCCUPANT SATISFACTION

▪ To meet target, post=occupancy evaluation (POE) is a useful diagnostic tools and system which
allows facility managers to identify and systematically evaluate critical aspects of building
performance based on the employee’s day to day experiences.
▪ As complement to technical monitoring or lifecycle analyses, surveys have a great potential
of gaining relevant feedback from the occupants as a basis for various improvements in
energy efficiency regarding day-to-day operations.
▪ Experiences show that there is often a gap between the calculated and the metered energy
consumption for a variety of reasons which can be assessed by continuous monitoring. This
is expected as well in the wide field of comfort.
▪ The data collected by the survey can be divided up into subjective and objective variables.
The objective variables measured include gender, age group, type of work, office type,
proximity to windows and exterior walls, and various types of control over workspace
environment, such as window blinds etc.
▪ The subjective variables measured include occupant satisfaction and self-reported
productivity with the following IEQ categories: office layout, office furnishing, thermal
comfort, air quality, lighting, acoustics, cleaning and maintenance, overall satisfaction with
building and overall satisfaction with building and overall satisfaction with workspace etc.
▪ Satisfaction can be based on various parameters – Thermal or IEQ comfort, spatial design
based comfort, safety etc


Occupant satisfaction can be measured even before the project starts or need to modify existing
structure. This type of survey understands the aspects that occupants are expecting from the design.

Correlations scores can be generated between a building’s performance and the occupant
satisfaction.

ANALYSING INDOOR AIR QUALITY

Indoor air quality refers to the air quality within and around buildings and structures as it relates to
the health and comfort of its occupants.Indoor air quality is affected by temperature, humidity,
ventilation, and chemical or biological contaminants found within the air inside a building.
Immediate Effects
Some health effects may show up shortly after a single exposure or repeated exposures to a pollutant.
These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Such
immediate effects are usually short-term and treatable. Sometimes the treatment is simply
eliminating the person’s exposure to the source of the pollution, if it can be identified. Soon after
exposure to some indoor air pollutants, symptoms of some diseases such as asthma may show up, be
aggravated or worsened.
Long-Term Effects
Other health effects may show up either years after exposure has occurred or only after long or
repeated periods of exposure. These effects, which include some respiratory diseases, heart disease
and cancer, can be severely debilitating or fatal. It is prudent to try to improve the indoor air quality
in your home even if symptoms are not noticeable
Primary Causes of Indoor Air Problems
Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air
quality problems. Inadequate ventilation can increase indoor pollutant levels by not bringing in
enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants
out of the area. High temperature and humidity levels can also increase concentrations of some
pollutants.
Pollutant Sources
• Tobacco products
• Building materials and furnishings as diverse as:
◦ Deteriorated asbestos-containing insulation
◦ Newly installed flooring, upholstery or carpet
◦ Cabinetry or furniture made of certain pressed wood products
• Products for household cleaning and maintenance, personal care, or hobbies
• Central heating and cooling systems and humidification devices
• Excess moisture
• Outdoor sources such as:
◦ Radon

◦ Pesticides
◦ Outdoor air pollution.
One important goal of an indoor air quality program is to minimize people's exposure to pollutants
from these sources. Some of the key pollutant categories include:
• Biological contaminants. Excessive concentrations of bacteria, viruses, fungi (including

molds), dust mite allergen, animal dander and pollen may result from inadequate
maintenance and housekeeping, water spills, inadequate humidity control, condensation, or
may be brought into the building by occupants, infiltration, or ventilation air.
• Chemical pollutants. Sources of chemical pollutants include tobacco smoke, emissions from
products used in the building, accidental spill of chemicals, and gases such as carbon monoxide
and nitrogen dioxide, which are products of combustion.
• Particles. Particles are solid or liquid substances which are light enough to be suspended in
the air, the largest of which may be visible in sunbeams streaming into a room. However,
smaller particles that you cannot see are likely to be more harmful to health. Particles of dust,
dirt, or other substances may be drawn into the building from outside and can also be
produced by activities that occur in buildings, like sanding wood or drywall, printing, copying,
operating equipment and smoking.
Inadequate Ventilation
• If too little outdoor air enters indoors, pollutants can accumulate to levels that can pose health
and comfort problems. Unless buildings are built with special mechanical means of ventilation,
those designed and constructed to minimize the amount of outdoor air that can "leak" in and
out may have higher indoor pollutant levels.
Outdoor air can enter and leaves a building by: infiltration, natural ventilation, and mechanical
ventilation.
• In a process known as infiltration, outdoor air flows into buildings through openings, joints,
and cracks in walls, floors, and ceilings, and around windows and doors.
• In natural ventilation, air moves through opened windows and doors. Air movement
associated with infiltration and natural ventilation is caused by air temperature differences
between indoors and outdoors and by wind.
• Finally, there are a number of mechanical ventilation devices, from outdoor-vented fans that
intermittently remove air from a single room, such as bathrooms and kitchen, to air handling
systems that use fans and duct work to continuously remove indoor air and distribute filtered
and conditioned outdoor air to strategic points throughout the house.

• The rate at which outdoor air replaces indoor air is described as the air exchange rate. When
there is little infiltration, natural ventilation, or mechanical ventilation, the air exchange rate
is low and pollutant levels can increase.
Design, Maintenance and Operation of Building Ventilation Systems
• Ventilation system design. The air delivery capacity of an HVAC system is based in part on the
projected number of people and amount of equipment in a building. When areas in a building
are used differently than their original purpose, the HVAC system may require modification to
accommodate these changes. For example, if a storage area is converted into space occupied
by people, the HVAC system may require alteration to deliver enough conditioned air to the
space.
• Outside air supply. Adequate supply of outside air, typically delivered through the HVAC
system, is necessary in any office environment to dilute pollutants that are released by
equipment, building materials, furnishings, products and people. Distribution of ventilation
air to occupied spaces is essential for comfort.
• Outdoor air quality. When present, outdoor air pollutants such as carbon monoxide, pollen
and dust may affect indoor conditions when outside air is taken into the building's ventilation
system. Properly installed and maintained filters can trap many of the particles in this outdoor
supply air. Controlling gaseous or chemical pollutants may require more specialized filtration
equipment.
• Space planning. The use and placement of furniture and equipment may affect the delivery
of air to an occupied space. For instance, the placement of heat generating equipment, like a
computer, directly under an HVAC control device such as a thermostat may cause the HVAC
system to deliver too much cool air, because the thermostat senses that the area is too warm.
Furniture or partitions that block supply or return air registers can affect IAQ as well, and need
to be positioned with attention to air flow.
• Equipment maintenance. Diligent maintenance of HVAC equipment is essential for the

adequate delivery and quality of building air. All well-run buildings have preventive
maintenance programs that help ensure the proper functioning of HVAC systems.
• Controlling other pollutant pathways. Pollutants can spread throughout a building by moving
through stairwells, elevator shafts, wall spaces and utility chases. Special ventilation or other
control measures may be needed for some sources.
• Use of IAQ sensors - In the IoT world, the use of sensors can play a huge role in analysing the
pollutant quality and concentration.

ANALYSING THE TYPES OF HVAC SUPPORTING THE BUILDINGS

HVAC System Selection
• System selection depends on three main factors including the building configuration, the
climate conditions and the owner’s desire.
• Some criteria can be considered such as climate change, building capacity, spatial
requirements, cost such as capital cost, operating cost, and maintenance cost, life cycle
analysis, and reliability and flexibility.
• Selection has a few constraints: available capacity according to standards, building

configuration, available space, construction budget, the available utility source, heating and
cooling building loads.
PSYCHROMETRIC CHART
▪ The psychrometric chart shows graphically the parameters relating to water moisture in air.
This application note describes the purpose and use of the psychrometric chart as it affects
the HVAC engineer or technician.
▪ The psychrometric chart indicates the properties of this water vapor through the following
parameters:
1. Dry bulb temperature
2. Wet bulb temperature (also known as saturation temperature)
3. Dew point temperature
4. Relative humidity
5. Moisture content (also known as humidity ratio)

6. Enthalpy (also known as total heat)

7. Specific volume (the inverse of density)
▪ If you know any two of the parameters, you can find the other five values from the chart.
▪ Why study of psychrometry is important:
1. people feel comfortable over a narrow range of temperature and humidity
2. machines (especially electronic machines) operate over a specific range of temperature
and humidity
3. to calculate the amount of heating or cooling required for a certain space requires
knowledge of the moisture content of the air
COMPONENTS OF PSYCHROMETRIC CHART
1. Dry bulb (DB) temperature: We measure the

temperature of the air with a thermometer. Traditional
thermometers have a bulb that contains a liquid that
expands, and a tube indicating the temperature on a
scale. As the liquid expands, it rises up the scale. This
measurement is called the dry bulb temperature
because the end of the thermometer that is making the
measurement has no moisture on it. The temperature of
the air is measured in °F or °C. This temperature is shown
as the horizontal axis of the chart.
2. Wet bulb (WB) temperature - The wet bulb temperature

is measured by having the bulb of the thermometer
moist. The moisture evaporates, lowering the
temperature recorded by the thermometer. Less
moisture in the air will result in a faster rate of
evaporation and therefore a colder reading. When the
air sample is saturated with water (that is, it has 100%
relative humidity), no water can evaporate from the
moist tissue so the WB temperature will read the same
as the DB temperature. This temperature is therefore
also referred to as the saturation temperature. This
temperature is indicated by diagonal lines on the chart.

3. Relative humidity (RH) - This is the ratio of the fraction

of water vapor in the air to the fraction of saturated
moist air at the same temperature and pressure. RH is
dimensionless, and is usually expressed as a percentage.
100% RH indicates the air is saturated and cannot hold
any more moisture. Lines of constant relative humidity
are shown as exponential lines on the psychrometric
chart. The line at 100% is referred to as the saturation
line.
4. Absolute Humidity (AH) - The amount of moisture

actually present in unit mass or unit volume of air, in
Absolute
terms of gram per kilogram (g/Kg) or gram per cubic
meter (g/m3). The absolute humidity is the vertical axis
of the chart.
5. Enthalpy (total heat) - Enthalpy (usually designated as h)

is the total amount of heat energy of the moist air and
therefore includes the amount of heat of the dry air and
the water vapor in the air. In the approximation of ideal
gases, lines of constant enthalpy are parallel to lines of
constant WB temperature. Thus the enthalpy is
indicated by diagonal lines on the chart
Enthalpy is measured in BTU per pound of dry air or
Joules per kilogram of air.
6. Specific volume - Specific volume is therefore the

volume per unit mass of the air sample. This is shown as
diagonal lines on the chart. Measured by cubic feet per
pound of dry air or cubic meters per kilogram of dry air.
7. Dew point (DP) temperature - This is the temperature of

the air at which a moist air sample reaches water vapor
saturation. It is equivalent to a wet bulb temperature at
100% relative humidity. At this combination of
temperature and humidity, further removal of heat
results in water vapor condensing into liquid.

SUMMARY OF LINES:
PSYCHROMETRIC CHART: PROCESSES

Design strategies can be found based on the each reference point (hour) of the year. The strategies
are aimed at bringing the reference point within the comfort boundary.

Classification of HVAC systems The major classification of HVAC systems is central system and
decentralized or local system. Types of a system depend on addressing the primary equipment
location to be centralized as conditioning entire building as a whole unit or decentralized as separately
conditioning a specific zone as part of a building. Therefore, the air and water distribution system
should be designed based on system classification and the location of primary equipment.
Four requirements are the bases for any HVAC systems. They need primary equipment, space
requirement, air distribution, and piping



BASIC COMPONENTS OF AN HVAC SYSTEM
o Mixed-air plenum and outdoor air control

o Air filter
o Supply fan
o Exhaust or relief fans and an air outlet
o Outdoor air intake
o Ducts
o Terminal devices
o Return air system
o Heating and cooling coils
o Self-contained heating or cooling unit
o Cooling tower
o Boiler
o Control
o Water Chiller
o Humidification and dehumidification
equipment
Analyzing the heat generated by the typology of building

Different typology of buildings have various ways by which heat can be generated. The following are
the various factors that plays a major role:
1. Choice of materials for the facade

2. Area, surface area and volume of the building
3. Occupancy levels
4. Equipment types
5. Equipment usage patterns
6. Need for certain environmental consideration
7. Lighting heat gain
Internal Heat Gains Internal heat gains correspond to heat that is generated in buildings as part of
their programmatic use. Internal heat gains in buildings are typically divided in to three groups:
1. Heat from occupants

2. Heat from electrical equipment and appliances
3. Heat from electric lighting
Internal Heat Gain from Occupants
▪ Same as individuals’ thermal comfort sensation varies, building occupants generate varying
amounts of heat and moisture. Key factors that determine how much sensible and latent
energy a person releases are activity, age, and gender.
▪ Sensible heat gains from occupants raise the indoor temperature. Latent heat gains need to
be considered if the indoorair is actively dehumidified.

▪ ‘Occupancy load schedules’ are determined through two factors: maximum occupancy heat
gains and time of day schedules.
▪ Maximum occupancy heat gains = (activity-related heat gain/person) x occupancy density
EXAMPLE:
1. Each person has 100 W of sensible heat. Maximum occupant density is 45 divided
over 12 m x 12 m.
The resultant maximum occupancy heat gain is:
(100 W/person) x (45 person/144m2) = 31 W/m2 = 0.31 person/m2
Schedules
The maximum occupancy heat gain corresponds to heat gains when everybody is at their work place.
Since occupants temporarily leave their building, ‘schedules’ are used in energy simulation software
in order to determine occupancy loads on different week days and for different times of the day
Equipment and Appliances
Heat gain due to a variety of equipment, including computers, coffee machines, hot water pipes etc.
Sun Wind and Light (Chapter 4) provides lower and upper margins for different building types:
Offices : 8 to 17 W/m2 (Studio load typically around 26 W/m2 )

Education: 14 to 23 W/m2
Residential: 2to 6 W/m2
Load
• The ideal load is the amount of heat that has to be added or subtracted from a space for it to
maintain the zone air temperature at a certain level.
• Load is measured inkWh or BTU.
• Normalising the load to the conditioned area helps to compare different spaces.
• The load of a space does not correspond to its energy use which requires further conversion
depending on the HVAC equipment used.
Thermal Zone
• Is a space or collection of spaces within a building having sufficiently similar space
conditioning requirements so that those conditions could be maintained with a single thermal
controlling device. A thermal zone is a thermal and not a geometric concept: spaces need not
be contiguous to be combined within a single thermal zone.
HVAC Zone
• An HVAC zone is a physical space within the building that has its own thermostat and zonal
system for maintaining thermal comfort. HVAC zones are identified on the HVAC plans. HVAC
zones should not be split between thermal zones, but a thermal zone may include more than
one HVAC zone.

UNIT 4: POST OCCUPANCY EVALUATION

PURPOSE OF POST-OCCUPANCY EVALUATION
Defining POE
• Post Occupancy Evaluation (POE) - Feedback about
how buildings perform and how they interact with
their users
• Provide useable information: – To help manage the
building – To be feedback into the brief for the next
building project
Role of POE - Manage Facilities by:

• Understanding how they are performing
• How users´ needs are changing
• Managing response to organisational change
• Feeding into the ´Brief´ for the next project
• Improving process of project delivery
POE
• Post-occupancy evaluation (POE) is the process of understanding how well a building meets
the needs of clients and building occupants.
• POE provides evidence of a wide range of environmental, social and economic benefits core
to sustainability.
• It can also address complex cultural issues such as identity, atmosphere and belonging.
There are three different kinds of reviews integral to POE:
o The effectiveness of the procurement process itself
o The performance of the built fabric and construction details
o The operational effectiveness of the building – in this case the ‘users’ need to be defined Once
objectives have been set POE can be planned and resourced
Purpose of POE:
• Applying sign skills more effectively
• Improving commission process
• Improving user requirement
• Improving management procedures
• Providing knowledge for design guides and regulatory processes
• Targeting of refurbishment
Post-Occupancy Evaluation will:

• Highlight any immediate teething problems that can be addressed and solved
• Identify any gaps in communication and understanding that impact on the building operation
• Provide lessons that can be used to improve design and procurement on future projects
• Act as a benchmarking aid to compare across projects and over time.

Occupant and client consultation

• Environmental comfort and control over environmental conditions
• Building impact on productivity and performance, staff and user retention and motivation
• Customer experience and user satisfaction with amenities, image and layout
• Review of design, procurement, construction and handover processes.
Monitoring of environmental conditions - including temperature, noise, light, air quality, ventilation
and relative humidity.
Assessment of design quality using BRE's DQM -a structured method for assessing design quality and
building performance against industry benchmarks and good practice.
Sustainability and utility audits - to measure and demonstrate the environmental performance of
buildings in use, to inform property management and energy efficiency strategies
COMPONENTS OF POST-OCCUPANCY EVALUATION

TECHNIQUES AND METHODS FOR POST OCCUPANCY EVALUATION
Three Approaches: Indicative, Investigative and Diagnostic POE

(1) Indicative POE, it is suggested, are cursory analyses that may include “quick walkthrough
evaluations involving structured interviews with key personnel, group meetings with end users as well
as inspections”
(2) Investigative POE are considered to be more in-depth analyses, utilising interviews and
questionnaires, usually across a number of buildings of the same or similar type.
(3) Diagnostic POE are regarded as being the most sophisticated of the methodologies. They tend to
have a broad, system wide focus on a number of comparable facility types, focusing on a broad range
of technological and anthropological areas of research. Preiser suggests that this type of in-depth POE
produces “high validity and generalisability of data collected... (that has) the potential of being
transformed into guidelines” for use in the public realm
Four General Typologies

(1) “building-behaviour research, or the accumulation of knowledge;
(2) information for pre-design programming for buildings for which design guides or prototypes may
be useful;
(3) strategic space planning – i.e. building assessment as part of ‘workspace change to bring space
more in line with strategic business goals’
(4) capital asset management – POE as a tool in developing performance measures for built space.”

ESTIMATING PREDICTED MEAN VOTE – PMV OF THERMAL COMFORT

▪ Thermal comfort is largely a state of mind, separate from equations for heat and mass transfer
and energy balances.
▪ However, the perception of comfort is expected to be influenced by the variables that affect
the heat and mass transfer in our energy balance model.
▪ The most common approach to characterizing thermal comfort for the purposes of prediction
and building design has been to correlate the results of psychological experiments to thermal
analysis variables.

▪ That is, human subjects with various clothing levels and

performing different activities are placed in environments
with different air temperatures and surface temperatures,
different humidities, and different airflow velocities and
patterns.
▪ The subjects are then asked to express their level of
comfort.
▪ The level of comfort is often characterized using the
ASHRAE thermal sensation scale.
▪ The average thermal sensation response of a large number
of subjects, using the ASHRAE thermal sensation scale, is
called the predicted mean vote (PMV).
The method developed by Fanger (1972) and adapted in ISO Standard 7730 is based on the
determination of the PMV index (Predicted Mean Vote) calculated from an equation of thermal
balance for the human body, involving the terms of internal generation and heat exchanges with the
surrounding environment.
Fanger’s PMV correlation is based on the identification of a skin temperature and sweating rate
required for “optimal” comfort conditions, using the data from Rohles and Nevins (1971).

The metabolic heat loss is the difference between the metabolic generation and that converted to
work (e.g., lifting, running).
With these conditions specified, Fanger correlated PMV as a function of the thermal load, L, on the
body, defined as the difference between the rate of metabolic heat generation and the calculated
heat loss from the body to the actual environmental conditions assuming these optimal comfort
conditions. The convection and radiation heat transfer are functions of clothing temperature, which
is affected by skin temperature. The evaporative losses are directly influenced by skin temperature.
The humidity ratio of the air in equilibrium with the skin under comfort conditions, Wsk,req, is the
saturated humidity ratio evaluated at the required skin temperature.
In the above equations, the clothing temperature is not directly known. However, the clothing
temperature can be easily calculated from the required skin temperature, the air temperature, mean
radiant temperature, and the thermal resistances.

The above equation for thermal load uses three other parameters that must be determined – fcl, hc,
and hr. There is no definitive set of values for all applications. When Fanger developed his original
correlation, he used the following approximations to these parameters:
Finally, Fanger, developed the following correlation between PMV and the thermal load. The predicted
mean vote is the average response of a large number of people. Given the subjective nature of
comfort, there will actually be a distribution of satisfaction among a large group of people. Figure to
the right shows an empirical relationship between the percentage of people dissatisfied (PPD) with a
thermal environment as a function of the PMV.

ESTIMATING PREDICTED PERCENTAGE OF DISSATISFIED – PPD OF THERMAL

COMFORT
ASSESSING THE BUILDINGS BASED ON THEIR ENERGY AND WATER USAGE

METHODOLOGY
The methodology for assessment of building energy performance data, can be focused from two
perspectives:

• (Top-down) What can be expected when different data are available for the EPB assessment, e.g.
Heating, Cooling, Ventilation, Appliances, Lights, Hot Water and location-based data
• (Bottom-up) What is required as input to the method if an EPB value with uncertainty of x% is
requested?
Use metering data (electricity, gas, heat, water, …) advantage is that a growing amount of data is
coming available and hence improved accuracy.
Objective
1 - Split building related energy use from occupants energy consumption
• EPB energy use; heating, cooling, ventilation, DHW and light
• Non-EPB energy use; appliances, gains, behaviour, …
2 – Benchmark the usage between similar neighbours
PROPOSED METHODOLOGY
1. Obtain the consumption meter readings of multiple users.
2. Determine the energy resources (electricity, gas, heat) used for cover the heating and
cooling demand of each user.
3. Obtain the additional info (administrative info, weather,…) based on user location.
4. Model the consumptions using exogenous variables
o Exogeneous variables could be outdoor temperature, solar radiation, wind speed,
weekday, hour of the day, day of the year,…
o Some coefficient should be used from holistic reference buildings.
o Regression and Generalized Additive Models (GAM) should be used.
o Model coefficients characterize the performance of the dwelling
o Model residuals would be considered as non-EPB energy use.
5. Using a clustering technique, determine the most common non-EPB energy use patterns
for each user User activity/occupancy patterns
6. Benchmark the EPB indicators against similar users (similar year of construction,
normalized by dwelling area, similar economic or cultural level, similar user
activity/occupancy, similar building type…). An aggregation to district level or other
administrative units.
7. Assess to retrofit, renew or manage the energy usage using the results of the
benchmarking.
A metering strategy shall be developed that enables total electricity, heat, gas and water usage in
individual dwellings to be captured for annual reporting, as applicable. The metering strategy should
also enable the total electricity, heat, gas, water and renewable energy of common parts to be
captured for annual reporting, as applicable
Energy consumption by end use (kWh/m2 /year)

i). Heating
ii). Cooling
iii). Auxiliary

iv). Lighting
v). Hot water
vi). Equipment
Energy production by technology (kWh/m2 /year)

i). Photovoltaic systems
ii). Wind turbines
iii). CHP generators
iv). Solar thermal systems
OPERATIONAL ENERGY:
❑ When presenting the operational
a. Total energy consumption, thermal (kWh/m2
/year) energy calculation results,
b. Total energy consumption, electricity (kWh/m2 provide ‘high’, ‘medium’ and
/year) ‘low’ energy use estimations for
c. Energy consumption by end use (kWh/m2 /year) all applicable end uses, where
i). Lighting reasonable.
ii). Small power
iii). Lifts and escalators ❑ It is intended that the operational
iv). Catering energy predictions will enable a
v). Server Rooms greater understanding of the gap
vi). Other equipment between design stage energy
vii). Domestic hot water, thermal consumption (regulated and
viii). Domestic hot water, electricity unregulated) and in-use
ix). Heating, thermal performance.
x). Heating, electricity
xi). Cooling WATER REPORTING
xii). Fans/AHU
Metering should allow
xiii). Pumps/controls/heat rejection
information on the following:
xiv). Renewable generation, thermal
1. Net water usage
xv). Renewable generation, electric
2. Net recycled water
3. Net rainwater harvesting
COLLECTION OF DATA WHICH IS REQUIRED BY THE PERFORMANCE

EVALUATION SOFTWARE
❑ Multitude of software are there to process the data. For qualitative analysis of
questionnaires or survey, software such as SPSS can come in handy.
❑ For quantitative analysis metering and monitoring equipment are used to process the data
❑ Data required requires planning of what is the goal to be achieved from the post occupancy
evaluation

FUNCTIONAL PERFRMANCE ELEMENTS
▪ Functional performance deals addresses the functionality and efficiency level of the features
in buildings and facilities.
▪ Functional elements include accessibility, spatial capacity for activities, and adequacy of
necessary facilities. Other elements include utilities, telecommunications, responsiveness to
change over time, and efficiency of communication and circulation. These elements are
directly connected to the activities within a building.
▪ They are required to be in conformity to the specific needs of the occupants
▪ This direct connection between a building's functional aspects and the needs of its users is
probably the reason for its receipt of noteworthy attention in POE studies
Technical performance elements

▪ Technical performance elements deal with survival attributes, such as structure, sanitation,
fire safety, and, ventilation, and health
▪ From an environmental perspective, technical performance addresses the issues of indoor
environmental quality (IEQ), which affect the comfort, health, and productivity of occupants
▪ IEQ elements include thermal comfort (HVAC system and natural ventilation system), indoor
air quality, visual comfort (the quantity and quality of lighting, glare, control of shadows,

luminance, and adequate luminance), and acoustical comfort (acoustic comfort relates
primarily to providing conditions in a building that facilitate clear communication of speech
between its occupants).
▪ Noise control can be provided through walls, floors, windows, and doors that provide
adequate reduction of sound from adjacent activities
Behavioral performance elements

▪ Behavioral performance elements create a link between occupants’ activities and the physical
environment.
▪ Typical behavioral performance issues include the effect of area size and number of persons
that share it upon a building’s occupant, and the effect of functional distance between spaces
upon the frequency of use.
▪ Moreover, occupants’ comfort is also affected by the configuration of circulation routes on
social interaction, and the features that affect the building's image and outlook
DESIGN QUALITY
1. Building layout
▪ The layout of space, furniture, and storage and the convenient circulation and accessibility
to various usable spaces within a building are of utmost importance to residential
satisfaction. Spatial attributes, the sequence, location, relationships, shape, size, and detail
of spaces have been shown to affect occupant behavior
▪ The interior layout of the building should be efficient in terms of the arrangement of rooms
in each level in the building, the width of the corridors for circulation, and the location and
number of stairs
2. Interior and exterior appearance
▪ Appearance is one of the most important aspects of building performance.

▪ It pertains to the aesthetic perception of the building by the occupants.
▪ Common problems that affect exterior walls are color fading, moisture and wind infiltration,
spalling, buckling, delamination, cracking, cleanability, and erosion.
▪ The quality of construction and selection of building materials should be compatible with,
and complement, the existing physical environment
3. Access to facilities– accessibility

▪ This refers to the building's closeness to the facilities on the campus, usually within a walkable
distance to teaching, recreational, food-consuming, and car parking facilities
▪ These facilities include sports facilities, parking lots, campus shuttle stations, worship centers,
grocery stores, food courts, medical centers, libraries, and academic buildings
▪ The location of a building and its proximity to places of interest are major factors in the
satisfaction of its occupants

INDOOR ENVIRONMENTAL QUALITY

1. Thermal comfort
▪ ASHRAE 55 (2004) defines thermal comfort as “the state of mind that expresses satisfaction
with the surrounding thermal environment.”
▪ The major influencers of thermal comfort in an indoor space are the HVAC system and
natural ventilation system through windows and other openings.
▪ Thus, comfort will be determined by the ability to control both systems
2. Indoor air quality
▪ IAQ is the quality of air within a facility or the built environment. Anderson et al. (2014)
define IAQ as “the comfortable range of the temperature, humidity, ventilation and
chemical or biological contaminants of the air inside a building.”
▪ The major concern is indoor air pollution, which can be the cause of asthma, allergies, and
irritation.
▪ Two of the most dreaded implications of poor IAQ are sick building syndrome (SBS) and
building-related illnesses (BRI)
3. Acoustic comfort
▪ “Acoustic criteria cover the ambient level of sound, the transmission of sound between
areas and rooms, reverberation, and specific areas such as machine noise and auditorium
acoustics”
▪ Indoor and outdoor factors influence acoustical comfort. Although indoor factors can be
controlled, outdoor factors are the primary causes of discomfort, and its control depends on
the filtering level of the building envelope
4. Visual comfort
▪ The Illuminating Engineering Society of North America (IESNA, 2000) defines visual comfort as
“an essential human need that can affect task performance, health and safety, and mood and
atmosphere.”
▪ The design of buildings and facilities creates balance between artificial and daylighting,
whereby sufficient natural light is allowed through transparent parts of the building envelope
5. Security and fire safety
▪ Security is defined as “the degree of resistance to, or protection from, harm. It applies to any
vulnerable and valuable asset, such as a person, dwelling, community, nation, or organization”
▪ Fire safety is one of the earliest elements to be evaluated systematically, likely because of
enormous concerns for life and property. Relevant criteria include the fire resistance of the
major structural elements of a building, fire extinguishment and containment, flame spread,
smoke generation, the toxicity of burning materials, and the ease of egress in case of a fire
▪ Security and fire safety are usually treated together as one technical performance element
because of their role in the protection of life and the property from disastrous events
Quality of building support services – QBSS

▪ Building services and infrastructures are an integral part of the built environment and a major
influence on satisfaction and quality of life of occupants.
▪ They include water supply, washrooms and water closets, laundry, information technology,
and electrical services

▪ These facilities should be properly designed, installed, maintained, and managed. Services,
such as electricity supply and warm water, must be adequate for the level of use.
▪ The availability and adequacy of these facilities coupled with the issues of the cleanliness of
washroom facilities are of utmost concern
MUTATION OF DATA COLLECTED FROM PASSIVE AND ACTIVE SYSTEMS

MODELING AND GENERATING BUILDING PERFORMANCE WITH RESPECT TO
THE PREVIOUS DATA AFTER THE OCCUPANCY DETAILS ADDED TO THE BUILT
FORM
▪ Buildings do not perform as modelled.
▪ There are many reasons for this, for example change of scope, functions, assumptions,
weather, user behavior and so forth.
▪ A weakness of building simulation is the necessity to predict the occupant behavior, in order
to predict the actual building performance.
▪ Studies have found that even efficiently designed and constructed buildings can consume
more energy and produce less energy than originally expected
▪ One of the main issues found is that the accuracy of the predicted performance is reliant on
the way the variables are used in building simulation to predict occupant behavior
▪ The literature provides precedence to predicting occupant behavior in influencing simulation
outcomes:
❑ Scheduling: Studying occupancy type and hours
❑ External factor controls: Studying the effect of temperature, humidity, wind and
rain, based on assumption of occupant behavior
❑ Assumption of occupants controlling windows to achieve necessary ventilation,
lighting, solar gain rates as intended by design
❑ How active and passive systems are managed based on occupant behavior based on
the above
▪ The occupant's choice of the type of controls to reach his/ her comfort is based on its
efficiency, ease and its potential unwanted consequences.
▪ We have identified actions (such as adjusting the level of clothing, opening a window and
turning down the thermostat temperature) and inactions (such as moving to a different
location and tolerating some discomfort) as differing strategies of occupants ‘behave’
(behaviour) towards the same thermal discomfort.
▪ These approaches, however, impact on the amount of energy use, and thus, it is important to
understand the relationship between the building and its users’ living style and their energy
use behaviour
▪ HVAC systems, electrical devices and lighting that enable users [occupants] to manage their
own thermal and visual comfort, are the key sources of energy consumption in buildings and
variations in using these systems can cause significant variations in the total energy
consumption in buildings, and hence, accounts for the gap between actual use and predicted
energy consumption.

▪ Occupant behaviour can be said to the

response people have to an external or internal
stimuli.
▪ They may adapt to the environment by the use
of passive and active systems
▪ A study by Sun and Hong in 2017, found that the
consumption range can be between 2% to 20%
based on the occupant behaviour style and
their interaction with energy conservation
measures
▪ Better occupancy data and usage patterns can
then be used to model the building for
simulation

UNIT 5: ADVANCED BUILDING SIMULATION AND ENERGY

BUILDING TEMPLATE MANAGER
The Building Template Manager (BTM) is the room template manager for the <Virtual Environment>
programs. It allows for easy designation of common zone features and conditions when constructing
a <Virtual Environment> model. BTM Window
The Building Template Manager window can be opened by selecting Templates > Building Template
Manager from the <VE> menus. The following window will then be displayed
The Building Template Manager is split up into 6 template types:

▪ Room Attributes
▪ Constructions
▪ MacroFlo Opening Types
▪ Thermal Conditions
▪ Electric Lighting
▪ Radiance Surface Properties

Room Attributes
This contains data relating to lettable area.
Lettable Floor Area - This is the percentage of the floor area that is lettable.
Circulation Floor Area - This is the percentage of the floor area that is classed as circulation.
Constructions
This section is where the opaque and glazed constructions are specified for templates.
It should be noted that the constructions template can only be used when drawing new geometry or
importing from file. We cannot apply a construction template to existing rooms within the model.
Opaque
This section contains drop down lists for the
following which are used to select the desired
construction:
❑ Roof
❑ Ceiling
❑ External Wall
❑ Internal Partition
❑ Ground Floor
❑ Door
Glazed
This section contains drop down lists for the
following which are used to select the desired
construction:
❑ Rooflight
❑ External Glazing
❑ Internal Glazing

EXAMPLES OF CONSTRUCTIONS:

Apache Constructions Database

Pressing this button opens up APcdb to allow for creation /removal / editing of constructions.
Thermal Conditions
This section is where room thermal conditions
are assigned to templates.
There are five tabs for thermal conditions data:
❑ Building Regulations - for VE Compliance
module
❑ Room Conditions - Heating & Cooling
❑ System - Apache Systems data
❑ Internal Gains - Casual Gains
❑ Air Exchanges - Infiltration & Ventilation
Building Regulations
This tab allows the template to be associated
with an NCM activity template for Building
Regulations compliance. Data entered here will
only affect VE Compliance and other thermal
modules (ApacheCalc, ApacheSim) will remain
unchanged.

Room Conditions
This tab contains controls for setting default room
heating attribute data.
Heating
Heating Profile This user can set the percentage

profile group that defines the operation of the
heating/cooling system. Note that for heating to
operate, the percentage profile must exceed 50%.
In most cases, prior to creating a template, the user
should define profiles using APpro. These profiles
will then appear in this and any other Percentage
Profile Group dialogue box.
Simulation Heating Setpoint This is the setpoint for

heating/cooling control. This value must be less than or equal to the Simulation Cooling Setpoint at all
times. The heating/cooling setpoint can be constant or it can follow a timed profile which can be
defined using APpro.
Heating/Cooling Zone (INACTIVE) This allows you to set a default heating zone to which spaces will
be assigned for the purposes of thermal calculations. *** Room grouping schemes provide this
functionality ***
DHW
Here we defined the DHW using either the occupancy profile or another predefined controlling
scheduling profile.
Consumption pattern
Here we can chose to control the DHW by either: Linked to space occupancy profile (default) OR
Independent profile
Pattern of use profile If “Independent profile” selected above then this is where we specify the
scheduling profile that describes the pattern.
DHW consumption The actual DHW consumption we want to define
Plant (auxiliary energy)
The plant (auxiliary energy) can be linked to either the heating or cooling profiles or indeed set
independently by assigning a controlling profile.
Plant profile (control) Here we set whether we want to link the control to one of the following: Set
to heating profile Set to cooling profile Set independently

Profile schedule Only active when “Set independently” above. This allows the selection of any
profile weekly modulating profile.
Model settings
Solar Reflected Fraction This is the fraction of solar radiation which, once transmitted by the glazing
room, is then rereflected out of the window. The value of solar fraction lost depends primarily on
internal surface emissivity and room geometry. As a general rule, windows which have a high room
view factor will have higher solar re-reflected fractions. For ApacheCalc only.
Furniture Mass Factor In ApacheSim the thermal mass of the air in a room is calculated as the product
of the room volume, the air density and the air specific heat capacity at the room conditions. See the
Apache User Guide for more information.
System
This tab contains controls for setting default room cooling attribute data
HVAC System
This is where the system that controls the room and supply air condition (set in Apache Systems) is
chosen for the current template. This choice dictates the efficiency and primary energy use of the
system chosen for heating, cooling, air supply, extraction and any auxiliary mechanical ventilation.
Auxiliary System
This is where the system that controls the supply air condition for any auxiliary ventilation (set in
Apache Systems) is chosen for the current template. This choice dictates the efficiency and

primary energy use of the system chosen for heating, cooling, supplying and extracting the auxiliary
system air.
DHW System
This is where the system that controls the domestic hot water (set in Apache Systems) is chosen for
the current template. This choice dictates the efficiency and primary energy use of the system chosen
for heating
System outside air supply
Minimum Flow Rate The supply air condition is set in the Apache Systems dialog. It is the air supply
that will be tempered by the system plant and the results will be seen separately from the room load.
Variation Profile This is the variation profile that will be applied to the system air supply. The
modulating profile can be set in APpro.
Additional Free Cooling Flow Capacity This indicates the maximum intake of outside air that is
available for free cooling. In the case of a naturally ventilated room, a value of 5 ach would be typical
to model ventilation by window opening. In the case of an air conditioned room, where the outside
air is brought in via the system, it would be usual to express the value in l/(s·m2 ) and a value of 0.5 in
l/(s·m2 ) would be typical. Note that this figure represents the additional outside air intake over and
above the minimum ventilation level.
Internal Gain Parameters
Type
There are seven types of casual gains available for

selection:
❑ Fluorescent lighting
❑ Tungsten Lighting
❑ Miscellaneous
❑ Machinery
❑ Cooking
❑ Computers
❑ People
Gain Units The units by which internal gains are defined. W/m2 or W for all gains other than People
which is set a W/P or W. Lighting gains have the additional option of lux. Holes and windows added
on a surface will reduce the floor area to be used in a W/m2 calculation. Using the W option can be
used to bypass this procedure, specifically for high level zones where a floor may be set as a 100%
hole.

Internal Gain Parameters
Occupant Density This value is used

to calculate the number of people
per room. Clicking on the column
header will allow the column to be
sorted numerically or reverse
numerically.
Maximum Power Consumption This

is the default peak rate of energy (or
fuel) consumption of the device
being described. Most casual gains
(such as lights and small machines)
consume energy (or fuel) as well as
emitting heat.
Radiant Fraction This represents the amount of sensible gain that is released as radiant heat (the
remainder is assumed to be convective).
Fuel Where the default casual gain being defined has an associated power, or fuel consumption, this
item defines the type of fuel that it uses. For example, lights would normally use electricity, but
cooking might use gas or electricity.
Variation/DImming Profile This contains a control to set the modulating profile group reference that
describes the variation/dimming of the heat gain throughout the year.
AIR EXCHANGES
This tab is used for entering default room air

exchange settings (infiltration, natural
ventilation and mechanical ventilation).
Air Exchange Parameters
Type There are three types of air exchange

available for selection: 1. Infiltration 2.
Natural Ventilation 3. Auxiliary Ventilation
Exchange Reference The reference name

which the user can enter for an air exchange.
Variation Profile This contains a control to set the modulating profile group reference that describes
the variation of the selected air exchange type throughout the year.
A/C Rate Units The units of an air exchange can be selected by the user from the drop down list.

Maximum A/C Rate This value is the

maximum number of air changes for a
given profile group, i.e. the air-change
rate assumed at those times when the
defined profile has a value of 100%, or
when there are no profiles used (as in
Apache Heat Loss calculations).
Adjacent Condition The condition may

be set to either: External Air – air at
outside temperature. External Air + Offset Temperature – air at outside temperature plus a
temperature offset. Temperature From Profile – a fixed temperature defined by a temperature profile.
Temperature Offset This sets the offset temperature to be used in conjunction with the outside air
temperature for the associated adjacent condition. This setting is only displayed if the adjacent
condition is set to External Air + Offset Temperature.
Temperature Profile This contains a control to set the absolute temperature profile group for the
associated adjacent condition. This setting is only displayed if the adjacent condition is set to
Temperature From Profile.
Radiance Surface Properties
This section is where the Radiance surface properties are assigned to templates.
Opaque This section contains drop down

menus for the following which are used to
select the desired surface:
❑ Roof
❑ Ceiling
❑ External
❑ Wall
❑ Internal Partition
❑ Ground Floor
❑ Door
Glazed This section contains drop down menus for the following which are used to select the desired
surface:
❑ Rooflight
❑ External Glazing
❑ Internal Glazing

MODELIT
The Viewport In order to simplify things we will only use the single viewport option. By default we get
the following view:
▪ The red cross-hair in the centre of the viewport is the model origin (0, 0), also note the "View
Selection" is set to "Plan".
▪ Click on GRID button to pop-up the "Grid Settings" window which shows the current grid.
▪ Click on the LOCK button to pop-up the "Locks" window which shows the current status.
Create Prism This option is activated by the PRISM button in the model toolbar. This pops-up the
"Shape Settings" window, from this we can name our prism, and define the base plane level (0m) and
the height of the prism (3m). Note the "Segments" field is inactive since it does not apply.

We click the left mouse button near to the model origin, remembering that in the locks settings the
grid option is active. This selects the point (0,0) as the first corner of the prism. As we move the cursor
a rubber-band rectangle will follow the cursor with its origin fixed at the (0,0) vertex. When the cursor
is positioned at the diagonally opposite corner position we can click the left mouse again to create the
prism. If you move the cursor around you will see that it does not matter which corner of the prism
we create first. If we make a mistake in selecting the first corner of our prism we can cancel this by
clicking the right mouse button. Having created this prism the command remains active until we select
some other option.
Here is our first diversion: Cancel the "Shape Settings" window. Go to the view toolbar and click on
the "View Selection" options and select the "Axon" option. The image in the viewport changes to this
view of the prism.
You will notice that in the "Axon" view a lot of the toolbar options are no longer active e.g. the shape
options (Extrude, etc.) and editing options (copy, move, etc.). These options are only available in a 2D
view e.g. "Plan", "Front", etc.
If you look at the "Model Browser" (by default at the left of the ModelIT workspace) you will see that
the prism we have created has been added to the
"Model".
When we go back into the "Plan" view, you

will notice that the view has automatically
been re-scaled to fit the prism:

Create Extruded Shape This option is activated by the EXTRUDE button in the model toolbar. This
pops-up the "Shape Settings" window, from which we can edit the required parameters (same as
prism).
We digitize the shape using the left mouse to click on the required grid points (the right mouse can be
used to delete the last vertex). When we have digitized the last point (as shown above) we can either
use the "Close Shape" button to complete the extrusion, or clicking on the first vertex has the same
effect.
Time for another diversion:
We have created two objects – a prism and an extruded shape. If we click on the "Model Viewer"
button we get the following window pops-up:
This gives a "solid" view of the objects we have created, since the default view is not very interesting
we can change this by dragging the left mouse button from left to right to rotate the view (press and
hold the left mouse button while moving).

Adding Glazing to a Model Select the extruded shape, click the "Move Down One Level" button to
move from the Model level to the Surface level. When you do this the viewport will change to only
show the selected object (usually in "Axon"), and the selected object will expand in the "Model
Browser"
Select the required surface (either by selecting from the viewport or from the "Model Browser"), go
down another level using the "Move Down One Level" button to move from the Surface level to the
Opening level. Again the viewport changes to show the selected surface in a normalized view.
You will notice that the "Add Door", "Add Window" and "Add Hole" buttons are now active. Click on
the "Add Window" button (by default it is in "Rectangular" mode). In the viewport click on the grid
point which is the bottom left corner of the required window and then the top right corner (the
rectangular window will rubber-band from the first vertex).
The window can be created from any corner to the opposite.
We remain in this mode until we select another option. Create two more windows on this surface:
We can now go back up a level using the "Move Up One Level" button

Applying "Simple Model" to Application To run SunCast on the simple model we have just created,
select the "Solar" option from the "Application" tab and then select "SunCast". This starts "SunCast"
(in this version of the SunCast runs as an external application) and automatically opens the current
project.
THERMAL TEMPLATE
Creating Profiles To set up thermal

templates for the project, we will first
create profiles, using the APpro (Apache
Profiles Database) utility. Profiles describe
the time variation of thermal input
parameters. Examples of their use include
scheduling plant equipment, modulating
casual gains and ventilation rates,
specifying the timing and degree of
window opening and defining time-varying
set-points and supply temperatures.
Profiles are of two types:
Modulating profiles are used to modulate inputs such as gains, ventilation rates and window opening,
and to schedule plant. They take the form of a time series of values in the range 0 - 1.

Absolute profiles are used to specify the time variation of variables such as setpoints and supply
temperatures. They take the form of a time series of a physical variable (most commonly
temperature).
Profiles should be created for daily, weekly and annual usages patterns. To start APpro, click the
Apache Profiles Database button.
THERMAL TEMPLATE
Creating Profiles
Profiles should be created for weekly and (optionally) annual usage patterns. There are pre-built
(system) weekly profiles for you to choose from.
If you want to review a particular weekly group, double-click it and you will see the daily profiles for
each day of the week.
If you want to review a particular daily profile, double-click the required day of the week and you will
see the daily profile graph:
To use system weekly profiles in your project, select the profiles shown below using your mouse and
the key, then click the Import button. They will be copied to the Project Profiles window.

Back in the Template Manager Window, click on Add Template to create another constructions
template and change the name of this template to ‘Constructions template 1’.
Make sure the Constructions Template 1 is selected. In the element category drop-down lists, select
the wall and window constructions you created earlier in the External Wall and External Glazing
categories. The constructions in each category shown below are now the ‘active’ constructions for this
template.
If required, when drawing rooms in ModelIT, you could then select the required thermal and
construction templates to apply to subsequently drawn rooms. To do this, in the room Shape Settings
window in ModelIT, click on the Room Templates button to expand the list of template types. From
the drop down lists for the Constructions templates and the Thermal Conditions templates, select the
required template names. These are then the ‘active’ templates which will apply to any rooms
subsequently drawn
Assigning thermal templates to selected rooms
From the Thermal Template drop down list, select the Offices template and then click on OK to assign
the information in this template to the selected rooms. Repeat the process by applying the Server
Rooms template to the three ground floor rooms.
Editing the thermal information for one selected room

If you wish to change the thermal information for a
selected room, you can do this by first selecting the
required room. Let’s select the Studio. Next, click the
Query button. Note that the Query facility will only be
available if one room only is selected.

Weather Data
There are three tabs on the APlocate window, one for location and site data, one for design weather
data (used by ApacheCalc and ApacheLoads only) and the other for simulation weather data (used by
ApacheSim only). APlocate has a selection wizard that assists the user in selecting weather data.
RUNNING APACHESIM
Performing a dynamic thermal simulation using ApacheSim Make sure you are in the Apache view in
the Thermal group of applications. At the bottom of the Apache View, click the ApacheSim (Dynamic
Simulation) button. The Apache Simulation window will appear

The results file will hold all the results from

the simulation. Vista, the results analysis
tool, will open this file when the simulation is
complete and you can view the results in
different ways. The default results file name
will be <project name>.aps. We will use the
default name for this tutorial.
Once the simulation is complete the Virtual

Environment view will automatically switch
from the Apache View to the Vista view. In
Vista you will be able to review the results
from the simulation
FLUCSDL

Preferences Dialogue Box
This dialogue box is displayed when you select Preferences on the Settings menu.
❑ Analysis dialogue box - select a style for the Analysis dialogue box – this may be displayed in
one of 3 styles – a dialogue box with all the items on one page, a property sheet with 6 pages,
or a “wizard” with 6 pages (equivalent to those on the property sheet). The wizard may be
simpler to use for beginners but requires more mouse clicks. The dialogue box is quicker for
experienced users.
❑ Results display - select the sections you want in the analysis results.
❑ Daylight threshold table – select whether you wish to display a general purpose table of
threshold areas or one suitable for LEED NC 2.2 Credit 8.1.
Analysis Dialogue Box The Analysis dialogue box allows you to run an analysis calculation. It may take
one of two styles, depending on the preference you have set using the Settings > Analysis option.
Dialogue Box Style The first style (default) is a

single-page dialogue box as shown here:
Property Sheet Style The second style is a

property sheet that has 5 pages:
❑ The Illuminance page

❑ The Margin page
❑ The Calculation quality page
❑ The Day lighting page
❑ The False ceiling page
Illuminance Page
Illuminance Type Specify the type of illuminance to calculate for working planes and task areas. Note
all other surfaces always use planar illuminance:
1. Planar (“horizontal”). This is the

simple illuminance on the receiving
plane. Usually this is a horizontal
plane, hence the term “horizontal”.
2. Perpendicular (“vertical”). This is the

illuminance on a plane passing
through the point and perpendicular
to the receiving plane. Typically the
latter is a horizontal plane, hence the
term “vertical”. It is used mainly for
environments where there are many

vertical surfaces to be illuminated, mostly facing in the same direction, e.g. a control room
with many display terminals.
3. Cylindrical. This is the average illuminance over the surface of a cylinder whose axis passes
through the point and is perpendicular to the receiving plane. Effectively this means that only
the component of the incidence angle parallel to the cylinder axis is taken into account.
4. Semi-cylindrical. Similar to cylindrical illuminance, but the cylinder is cut in half by a plane
parallel to its axis. This means it is treated in the same way as cylindrical illuminance, except
that there is a cut-off when the component of the incidence angle perpendicular to the
cylinder axis exceeds +/- 90 degrees.
5. Scalar. This is the average illuminance over the surface of a sphere
Margin Page
Working Surface Margin
Enter the margin to be left uncalculated at the

edges of working surfaces. Because the grid size is
constant, the calculations will be inaccurate when
the working surface is close to a room surface. The
CIBSE-recommended margin is 0.5m.
Calculation Quality Page
Quality slider Use this to select from a number of

predetermined quality settings. The text below will
change as you move the slider to give you more
detail about the quality setting.
Advanced button This will show the Advanced

Quality Settings dialogue box, where you can set
the calculation quality at a higher level of detail.
Include room components toggle button Select

this if you have placed components in the room,
and you need these to be taken into account.
Include a ground plane toggle button Select this if you wish a ground plane to be included in the
calculation.
Day Lighting Page
Sky model Select the sky model to use - the CIE Standard Overcast Sky, the Uniform overcast sky, or
the CIE Clear sky. The first two are defined as functions of the value of Zenith Luminance, Lz, entered

below. The last one does not need these values – instead it is a function of latitude, longitude, date
and time. The latitude and longitude may be set in the Settings->Location… menu option. The date
and time must be selected below
Zenith Luminance Enter the zenith luminance Lz

of the sky model. The luminance Lγ,a at
elevation γ and azimuth a is given by: For the CIE
Standard Overcast Sky: Lγ,a = Lz (1 + 2 sin(γ))/3
For the Uniform Overcast Sky: Lγ,a = Lz The next
field will be calculated automatically if you enter
a value here.
Date and time This is needed if you select the

CIE Clear Sky model. Select the date either by
selecting the day or month text and entering the
text or using the spin buttons.
Simulations can be made for daylight factor and illuminance. Threshold can be calculated.

REFERENCES:
1. Clarke, J.A., “Energy simulation in building design”, Adam Hilger Ltd, Bristol, 1985
2. Energy Audit of Building Systems–MoneefKrarti (Ph.D)–CRC Press 2000
3. Givoni Baruch, “Passive and Low Energy Cooling of Buildings”, Van Nostrand Reinhold, NewYord, 1994.
4. Preiser, Wolfgang F. E., and Jacqueline Vischer. Assessing Building Performance. Routledge, 2015.
1. Integrated Environmental System, User Guides <Virtual Environment 6.0)
2. Szokolay, Steven V., “Introduction to Architectural Science: The basis of Sustainable Design”,
Architectural Press, Elsevier Science, Oxford, 2004
3. Szokolay, Steven V., “Solar Geometry”, Passive and Low Energy Architecture International, 1996
4. Phillips, Derek., “Daylighting: Natural Light in Architecture”, Architectural Press, Elsevier, Oxford, 2004
5. Alta, Hasim et al., “Building Performance and simulation”, 2016
6. Hensen and Lambert, “Introduction to Building Perforance Simulation’, 2011
7. Sousa, Joana., “Energy Simulation for Buildings: Review and Comparison”
8. Bahar et al., “A simulation Tool for Building and its Interoperability through the Building Information
Modeling 9BIM) Platform”, 2013
9. IEA EBC Annex 57. “Basics for the Assessment of Embodied Energy and Embodied GHG Emissions for
Building Construction”, 2016. – International Energy Agency
10. Tien, Wei, “A review of Sensitivity Analysis Methods in Building Energy Analysis”, 2012
11. Tugram et al., “A Simulation based Comparison of Correlation Coefficients with regard to Type I Error
Rate and Power”, 2015
12. Berger et al., “On the Comparison of three numerical methods applied to building Simulation”, 2019
13. Maria, Anu., ‘Introduction to Modelling and Simulation”, 1997
14. American Institute of Architects., “Architect’s Guide to Building Performance”
15. Koenigsberger et al., “Manual of Tropical Housing”
16. American Institute of Architects., “Architect’s Guide to Building Performance”
17. Szokolay, Stevem V., “Introduction to Architectural Science ; The Basis of Sustainable Design”, 2004
18. Szokolay, Stevem V., “Solar Geometry”,
19. Elbeltagi, Emad., “Contruction Site Layout Planning”
20. Nayak and Prajapati, “Handbook on Energy Conscious Buildings”, 2006
21. Better Building Partnership, “Sustainability benchmarking Toolkit for Commercial Buildings: Principles
for Best practices”, 2010
22. Ekbatan and Wagner, “Assessment of Occupant Satisfaction in Building Performance Evaluation based
on Systematic Surveys”, 2014
23. Khoshbakht et al., “Green Building Occupant Satisfaction: Evidence from the Australian Higher
Education Sector”
24. Spaul, Wil a., “Building-related factors to consider in indoor air quality evaluations”., 1994
25. Senitkova, Ingrid Juhasova., “Indoor Air Quality – Building Design”, 2016
26. Seyam, Shaimaa., “Types of HVAC Systems”, 2018
27. Silva, Manuel Carlos Gameiro da., “Spreadsheets for the calculation of Thermal Comfort Indices”
28. Odemakin and Alibaba., “Analysis of energy and water consumption in an apartment building”, 2019
29. Mustafa, Faris Ali., “Performance assessment of buildings viapost-occupancy evaluation: A case study
ofthe building of the architecture and softwareengineering departments in SalahaddinUniversity-
Erbil, Iraq” 2016
30. Lombard et al., ‘A review on building energy consumption information”, 2007
31. Schwartz et al., “Integrated Building Performance Optimisation: Coupling Parametric Thermal
Simulation Optimisation and Generative Spatial Design Programming., 2017

32. An Assessment of Energy Technologies and Research Opportunities., “Chapter 5: Increasing Efficiency
of Building Systems and Technologies”, 2015
33. Federal Facilities Council., “Learning from our Buildings: A state of the proactive summary of Post-
Occupancy Evaluation”, 2001
MANUALS FOR RATING SYSTEMS:
1. GRIHA Manual
2. IGBC Green New Building Rating system
3. LEED v.4
4. BREEAM International New Construction 2016
MANUALS FOR IES-VE (USER GUIDES)
1. Integrated Environmental Solutions, Virtual Environment – Module Tutorial

2. IES-VE ModelIT User Guide
3. IES-VE Radiance User Guide
4. IES-VE ApacheSim User Guide
5. IES-VE CFD: MicroFlo User Guide
WEBSITES
1. https://www.wbdg.org/design-objectives/accessible
2. https://www.iesve.com/discoveries/article/3813/ten-key-daylight-and-electric-metrics
3. https://www.phsc.co.uk/thermal-comfort-in-your-workplace/
4. https://www.epa.gov/indoor-air-quality-iaq/introduction-indoor-air-quality
5. https://ocw.mit.edu/courses/architecture/4-401-environmental-technologies-in-
buildings-fall-2018/lecture-slides-1/MIT4_401F18_lec16.pdf
6. https://www.wbdg.org/design-objectives/functional-operational
7. https://omrania.com/insights/the-multiple-meanings-of-function-in-architecture/
8. http://ceae.colorado.edu/~brandem/aren3050/docs/ThermalComfort.pdf


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SRM Institute of Science & Technology

(Deemed to be university u/s 3 of UGC Act, 1956)

19ARC709L - PERFORMANCE EVALUATION

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

UNIT 1: INTRODUCTION TO BUILDING PERFORMANCE EVALUATION

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

Performance Evaluation through Simulations: THE NEED

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

Performance Evaluation through Simulations: COMPUTATIONAL MODELING AND SIMULATION

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

Understanding Architectural Computation for Performance Evaluation

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

B. Indoor Air Quality Simulation (IAQ)

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

E. Lighting Comfort (Visual Comfort – Daylighting and Glare Analysis)

E. Lighting Comfort (Visual Comfort – Daylighting and Glare Analysis)

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

The Objectives of GRIHA:

Five ‘R’ Philosophy

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

GRIHA RATING CRITERIA

GRIHA ENVIRONMENTAL CATEGORY

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

Examples of Simulation Software accepted by GRIHA

USE OF SIMULATIONS IN GRIHA

Criterion 13: Optimize building design to reduce conventional energy demand

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

The Objectives of LEED:

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

LEED Credit Categories

List of approved LEED software

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

Simulation Approach to gaining credits

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

Introduction to Performance Audit: Introduction to Building Performance

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

Building Template Manager

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

• Option to assign constructions and/or Macroflo properties to openings based on current

ModelViewerII Visualisation Options

Solar Shading / Solar Arc Options

ApacheSim is comprised of the following tools:

Data Entry Options

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

▪ Sensible and latent gains from lights, equipment and occupants

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch

Building and System performance indicators include:

PERFORMANCE EVALUATION TOOLS FOR SUSTAINABLE BUILDINGS – M.Arch