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CHARTERED INSTITUTION OF BUILDING SERVICES

ENGINEERS HEAD QUARTERS RENEWABLE ENERGY
INTEGRATION FEASIBILITY

Prepared for: STUART BROWN

DEPUTY CHIEF EXECUTIVE

22 BALHAM HIGH ROAD

LONDON

SW12 9BS

Prepared By: Tejash Roy

Student No: 0400661
Date: February 2011
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TABLE OF CONTENTS

1.0INTRODUCTION...............................................................................................................3

...........................................................................................................................................3

Table 1 .............................................................................................................................3

.................................................................................................................................4

Table 2 ............................................................................................................................4

2.0QUANTITATIVE DESCRIPTION OF THE ENERGY PROBLEM POSED TO THE

BUILDING OWNERS AFTER THE ACTION ENERGY SAVING REPORT ...........................6

3.0DESCRIPTION OF POSSIBLE SOLUTIONS USING RENEWABLE ENERGY

TECHNOLOGIES ..................................................................................................................6

4.0DISCUSSION OF THE ANALYSIS OF SUITABILITY FOR APPLICATION, CARRIED

OUT USING RETSCREEN...................................................................................................10

5.0DESCRIPTION OF PROBLEMS FOR APPLICATION....................................................12

6.0CONCLUSIONS AND RECOMMENDATIONS ...............................................................12

APPENDIX 1 – RETSCREEN PRINOUTS

APPENDIX 2 – PRODUCT DATA SHEETS / INFORMATION

This report is confidential to Stuart Brown and is not to be passed on to or relied

upon by any third party. The Contracts (Rights of Third Parties Act) 1999 is
excluded by agreement of Tejash Roy and Stuart Brown from applying to the
Contract between them to provide this report to the maximum extent permitted by
law.
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1.0 INTRODUCTION

1.1 Tejash Roy, Renewable Energy Engineer, has been requested by Stuart

Brown, Deputy Chief Executive for the Chartered Institution of Building

Services Engineers (CIBSE), to assess the feasibility of implementing

renewable energy technologies at the CIBSE headquarters.

Electrici
ty Gas Total

220'0
Annual energy use (kWh) 88'700 00
£4,20 £11,1
Annual energy cost (inc VAT) £6,900 0 00
Unit cost (p/unit) 7.78 1.91
kWh/m2 floor area 74 183

41'80
Carbon dioxide emissions (kg CO2) 31'100 0 79'900
Carbon dioxide emissions per area (kg
CO2/m2) 32 35 67

Table 1 i

1.2 Table 1 shows the annual energy use and cost, and related carbon dioxide

emissions of the CIBSE headquarters.

1.3 This report follows on from an Energy Survey Report, issued by Target

Energy Services Ltd. The report recommends measures to cut the energy

cost by £3’900 (35%) per annum, for an investment cost of £4’700 with a

payback period of 1.5 years. This will achieve an estimated 33% savings in

CO2 emissions.ii Post implementation of the measures recommended by

Target Energy Services Ltd are shown in Table 2.

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Electrici
ty Gas Total

128,4
Annual energy use (kWh) 68,700 00
£2,40 £7,20
Annual energy cost (inc VAT) £4,800 0 0
Unit cost (p/unit) 7.78 1.91
kWh/m2 floor area 57.3 106.8

24,39
Carbon dioxide emissions (kg CO2) 22,500 0 46890
Carbon dioxide emissions per area (kg
CO2/m2) 18.8 20.3 39.1

Table 2

1.4 The measures recommended can be seen in Table 3. The changes are aimed

optimising the building envelope and reducing demand by energy efficiency

measures in the active systems, and thus achieving a cost saving. This is a

sensible option for addressing carbon emissions mitigation.

1.5 The measures recommended have been assumed to have been

implemented, and thus the base load defined for this feasibility study is shown

in Table 2, unless they are in conflict with the recommendations made in this

report, in which case they shall be dismissed.

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Estimated annual
saving Paybac
Budget
CO2 k
Measure capital
Cost Energy saving period
cost (£)
savin saving (kg (years)
g (£) (kWh) CO2)

1. Use PC power-down or turn 700 10000 4,300 0 3.3

off at night
2. Negotiate energy supply 700 0 0 0 3.1
contract and VAT CCL liability.
3. Heating operational and 800 44400 8,440 500 3.5
minor measurements
4. Revise lighting control 600 8600 3,700 1,200 3.2
procedures and install
presence detection in selected
areas
5. Install urinal and tap water 150 0 0 300 3.9
flow controls.
6. On replacement of boilers, 650 36100 6,860 1,500 3.7
install condensing boilers for
separated variable heating
circuits.
7. Replace T12 light fittings in 100 1400 600 400 3.1
corridors and publications
store.
8. Align and seal metal framed 200 11100 2,110 800 3.8
single glazed windows

26,01
Total 3900 0 4700

Table 3

1.6 The areas of focus for this report are to be:

• A quantitative description of the energy problem posed to the building

owners after the Action Energy Saving report;

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• A description of possible solutions using renewable energy

technologies;

• A discussion of the analysis of suitability for application, carried out

using RETScreen;

• A description of problems for application;

• Conclusions and recommendations.

2.0 QUANTITATIVE DESCRIPTION OF THE ENERGY PROBLEM POSED TO

THE BUILDING OWNERS AFTER THE ACTION ENERGY SAVING

REPORT

2.1 Following the changes made by the Action Energy report, the CIBSE
headquarters are not a zero-emissions building.

2.2 As the headquarters are for the Building Services Engineers, it should be
made an example of how to achieve zero-emissions for a modernised
Victorian office building.

2.3 The optimal method of achieving this goal should be by implementing a range
of renewable energy technologies.

2.4 The challenges posed with implementing these technologies can be related to
planning issues, ease of installation (as the construction process should aim
to be carbon neutral), economic feasibility, maintenance required by the new
systems, and the performance of the systems in regards to producing the
required energy demand.

3.0 DESCRIPTION OF POSSIBLE SOLUTIONS USING RENEWABLE

ENERGY TECHNOLOGIES

3.1 The following are possible renewable energy technologies that could be used:

• Building Integrated Photovoltaics;

• Wind energy power;

• Biomass heating;

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• Solar air heating;

• Solar Water heating;

• Ground source heat pump;

• Combined heat and power (cogeneration).

3.2 I shall briefly describe each of the above technologies with respect to how
they could be applied in CIBSE’s context.

Building Integrated Photovoltaics (PV)

3.3 This technology converts solar irradiation into DC energy. They are usually
roof mounted, facing southwards and are tilted at 30 degrees to maximise
performance.

3.4 The system is made up from roof mounted solar panels, batteries to store the
energy, invertors to convert the DC power into AC power, a controller to
manage the energy storage and deliver power, and the fixed structure to
mount the PV modules.

3.5 Each PV module is made of solar cells. A single cell can generate roughly
1.5W and 0.5V under optimum conditionsiii. The cells are joined in series and
parallel to meet the desired load conditions.

3.6 The downside with PV’s is that they are very costly to install, have a long
payback period, and require replacing after approximately ten years, and the
power generated by them is unreliable; as they rely on the weather conditions.

Wind energy power

3.7 The UK is Europe’s windiest country. Electricity is generated from the wind by
means of using the wind velocity to drive a geared rotor and turbine to
generate the electricity.

3.8 Wind speed increases with height above ground and is fastest offshore or in
coastal regions. The amount of power generated from the turbine varies with
wind speed. Hence the most reliable generation is when wind velocity is more
uniform over long periods of time.

3.9 The downside with wind turbines is the noise from the turbine, the visual
impact and electromagnetic disruption.

Biomass heating

3.10 These systems burn plant or other organic matter to generate heat. Earth
annually generates 130 billion tonnes iv which roughly equates to 6 years of
the world’s year 2000 energy use.

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3.11 Although the actual burning of the fuel releases carbon into the atmosphere,
however when the plants are grown they absorb the equivalent amount in
photosynthesis, hence the carbon neutral fuel source.

3.12 Biomass heating can be implemented simply to existing gas fired or oil
burning systems, with a new system of storing and/or growing the fuel to be
considered.

3.13 Biomass boilers can also form a valuable source of heat for combined heat
and power (CHP) systems, which will be explained in more depth later.

Solar Air Heating (SAH)

3.14 Also known as solar wall heating, is widely used to heat ventilation air
buildings. It is a relatively new technology for heating air with solar energy.
They are used as cladding of exterior, south facing walls, and can be cost
effective for new builds or retrofits to existing walls.

3.15 The system comprises of a solar collector mounted on the building, and a fan
and air distribution system installed inside the building. The wall is designed
as a perforated plate as the solar collector. As the air passes through the
small holes in the plate, it gets heated and gets ducted into the building.

3.16 The only power usage is the fan load to drive flow throughout the duct system
within the building. During summer months, a bypass damper can be opened
to avoid an unnecessary air conditioning load.

3.17 As with PV, the system relies heavily on the presence on solar radiation.

Solar Water Heating (SWH)

3.18 Similar to SAH, the system utilises incident solar irradiation to heat water for
heating load or direct usage. The system consists of a solar collector, control
system, pump, and storage tank.

3.19 As with PV, the system relies heavily on the presence of solar radiation, but
backup can be made available in the form of an immersion heater in the water
tank.

Ground Source Heat Pump (GSHP)

3.20 This system utilises the abundant energy stored within the earth itself from
solar radiation. As 46% of solar radiation is absorbed by the earth, v an option
for building heating and cooling would be to utilise this large thermal load.

3.21 As the ground transports heat slowly and has a high thermal heat storage
capacity, the temperature changes very slowly over the course of a year. A
topsoil layer of soil and groundwater below, allows the temperature of the
earth to be lower than ambient air at summer and warmer in winter.

3.22 GSHP systems work in a similar fashion to refrigeration systems, however it

can be reversed to provide heating in winter. Typically, the heat pump used to

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transfer heat energy, can work with an efficiency of approximately 300%, i.e.
for every 1kw of pump work delivers 3kw of heating/cooling load.

3.23 Heat is extracted from the ground using a series of buried pipes either in a
horizontal array, or in vertical bore holes, depending on space available.
Typically water or a water-antifreeze mix is used as the working fluid on the
system. As the temperature gains are lower than a typical gas fired or oil
burning boiler, a forced convection heater or large radiators should be used
and kept on constantly to provide the necessary temperature.

Combined Heat and Power (CHP)

3.24 CHP systems utilise the waste exhaust gas from the heating system to
produce steam and turn a turbine, and hence produce electricity. Therefore
rather then heating systems having low efficiencies in the range of 40%, using
this heat capture, efficiencies as high as 80% can be obtained.

3.25 Any number of heat generation technology can be used, i.e. coal fired, gas
fired or biomass. The system should be sized such that it can be left running
constantly for optimum efficiency. Therefore a detail profile on the viability for
the need for constant thermal and power loads should be determined.

Overall Choice of technologies for implementation

3.26 It is recommended, that the following measures be considered:

• A Wind Energy Solutions WES 18-30m 80kW wind turbine;

• 25 (31.9 sq.m) off Apin solar mono-Si SP190 Solar photovoltaic panels
with a combined 4.75kw output, mounted on the conference centre
roof;

• A Hargassner 49kW wood pellet biomass heating with steam turbine

CHP function;

• A McQuay Ground Source vertical bore 2.2 kW heat pump.

3.27 It is recommended that the biomass heating produce the majority of the
heating load for the building, with the CHP function being used to power the
GSHP and charge batteries. During summer months, when the heating load
decreases, the system will be controlled to produce a greater amount of
electricity.

3.28 The GSHP will only need to be used to produce intermediate temperature air
ventilation constantly throughout the year. Due to the CIBSE building location,
a large system of buried pipework will not be possible. In the summer months,
it will be used constantly to provide very efficient cooling.

3.29 The current air conditioning system will be kept in place, to provide peak load
demand on the hottest days of the year.

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3.30 It is recommended that the wind turbine and PV array be used to provide the
building’s electricity demand, taking load from the battery when supply runs
low, i.e. an overcast settled day.

3.31 It will be expected that excess electricity can be exported back onto the
national grid, which will also be connected to the buildings supply, in event of
an emergency, and also sold, as a source of revenue.

3.32 This system will ensure that the building has full energy functionality
constantly throughout the year, regardless of whether one or two of the
energy systems are out of service or cannot supply the necessary load
demand.

4.0 DISCUSSION OF THE ANALYSIS OF SUITABILITY FOR APPLICATION,

CARRIED OUT USING RETSCREEN

4.1 RETScreen does not allow the entire proposed energy production system to

be simulated as a single whole project. Rather it breaks each type of energy

usage down individually. This has the advantage of being able to closely

modify the parameters for each energy system, but does not allow full system

implementation to the order which would maximise the realism for a feasibility

analysis.

4.2 The full printouts for the energy systems analysis can be found in the

appendices.

4.3 All systems were analysed financially with 2% inflation, a 20 year project

lifecycle, a 70% debt ratio, and a debt term of 10 years with 5% interest.

Combined heating and cooling

4.4 The Biomass boiler can produce 49kW of heating capacity, which is 123% of

the required load for the building. By controlling the load of the boiler, the

power output from the CHP function will reduce the building’s electricity

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demand from solar and wind sources. The GSHP supplies 95.2% of capacity,

so the existing a/c system can be kept in place to supplement on peak load

days.

4.5 The use of cheap wood pellets, would give an annual savings of £4’350 on

fuel. Including O&M costs and debt repayments, the annual cost of the

combined renewable system would be £4’705. This equates to a simple

payback period of 8.5 years.

4.6 The system would contribute a net annual GHG emission reduction of 29.4

tonnes of carbon dioxide.

N.B The system modelled has not considered the costs and benefits of the

CHP function of the system; however the electricity cost for GSHP is

negligible.

Photovoltaics

4.7 The 25 units of the PV panel, when implemented in London, have a capacity

factor of 10.4% and deliver 4.3 MWh to the load.

4.8 The initial cost of the energy system is characteristically high at £53’284.

However even at this, with debt repayments, as there is no fuel charge, the

simple payback is 8.4 years, with an annual GHG emission reduction of 64.7

tonnes of carbon dioxide.

Wind

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4.9 Although rated at 80kW, due to the location, only 9.4% of the capacity can be

utilised. However, this is sufficient to supply 65.9 MWh to the load, with only

2.7 MWh needed annually from the grid (batteries).

4.10 With a low initial cost of £5’500 and no fuel costs, the annual savings on grid

electricity is such that the system will repay itself within a year, and as such

offers 59 tonnes of carbon dioxide savings per year.

5.0 DESCRIPTION OF PROBLEMS FOR APPLICATION

5.1 The initial drawback with the wind turbine will be planning permission. With a

hub height of 30m and 18m rotor, choosing an appropriate location which

maximises efficiency while gaining planning approval will be a problem.

Due to the complexities of the integration of all the systems, most of them will

only be able to become fully operational when the entire system I installed,

thus meaning careful planning of the logistics and construction process will

lead to the lowest lead time before the benefits from the cheaper energy can

be seen.

6.0 CONCLUSIONS AND RECOMMENDATIONS

6.1 It is recommended that all the renewable energy technologies be

implemented.

6.2 Renewable energy sources, when the complete system of integration is

considered and installed together, can power the entire CIBSE headquarters

with a relatively low payback period, with all the accompanying carbon

reductions.

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6.3 RETScreen has shown how each individual system can work autonomously

from each other and thus allowing a degree of flexibility within its design rules.

6.4 The Government have released some renewable energy generation

incentives for businesses and individuals. A summary of these include:

Feed in Tariffs, whereby payement is made for the electricity that is generated

in the business and also additional payment for renewable energy that is

surplus and as such sold back to the grid.

Renewable heat incentive, whereby an estimate is made on the amount of

heat produced by renewable sources, and a payment is made. These factors

have not been considered in the RETScreen analysis, but would further

reduce the cost of implementation and payback periods, while also generating

a constant revenue stream.

References

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i
Assignment/Coursework proforma – ME5521
ii
Target Energy Services Report – 00924/Exp/195/00/012 ENQ 006559
iii
Renewable Energy Technologies Coursebook – Part 2 – Brunel University
iv
Renewable Energy Technologies Coursebook – Part 2 – Brunel University
v
Textbook – GSHP - RETScreen