HVAC stands for heating, ventilation, and air conditioning. It controls the indoor environment by providing thermal comfort and maintaining good indoor air quality through temperature, humidity, air movement, air composition, and pressure control. HVAC load calculations are important for selecting the appropriate HVAC system capacity for a location. The calculations can be done manually using industry reference books or software. The process involves collecting building data, entering it into an HVAC load calculation form, determining indoor and outdoor design conditions, accounting for factors like infiltration and internal loads, and calculating the total sensible and latent heat loads to determine the required cooling/heating capacity.
HVAC stands for heating, ventilation, and air conditioning. It controls the indoor environment by providing thermal comfort and maintaining good indoor air quality through temperature, humidity, air movement, air composition, and pressure control. HVAC load calculations are important for selecting the appropriate HVAC system capacity for a location. The calculations can be done manually using industry reference books or software. The process involves collecting building data, entering it into an HVAC load calculation form, determining indoor and outdoor design conditions, accounting for factors like infiltration and internal loads, and calculating the total sensible and latent heat loads to determine the required cooling/heating capacity.
HVAC stands for heating, ventilation, and air conditioning. It controls the indoor environment by providing thermal comfort and maintaining good indoor air quality through temperature, humidity, air movement, air composition, and pressure control. HVAC load calculations are important for selecting the appropriate HVAC system capacity for a location. The calculations can be done manually using industry reference books or software. The process involves collecting building data, entering it into an HVAC load calculation form, determining indoor and outdoor design conditions, accounting for factors like infiltration and internal loads, and calculating the total sensible and latent heat loads to determine the required cooling/heating capacity.
HVAC stands for heating, ventilation, and air conditioning. It controls the indoor environment by providing thermal comfort and maintaining good indoor air quality through temperature, humidity, air movement, air composition, and pressure control. HVAC load calculations are important for selecting the appropriate HVAC system capacity for a location. The calculations can be done manually using industry reference books or software. The process involves collecting building data, entering it into an HVAC load calculation form, determining indoor and outdoor design conditions, accounting for factors like infiltration and internal loads, and calculating the total sensible and latent heat loads to determine the required cooling/heating capacity.
Download as DOCX, PDF, TXT or read online from Scribd
Download as docx, pdf, or txt
You are on page 1/ 4
HVAC
HVAC stands for
- H - Heating - V - Ventilation - AC - Air Conditioning
HVAC controls the indoor environment. It provides thermal comfort and maintain good indoor air quality. HVAC is also referred to as climate control because it fulfills following comfort requirements:
Temperature Humidity Air Movement Air Composition (Fresh Air & Cleanliness) Pressure A heating system (“H” in HVAC) is designed to add thermal energy to a space in order to maintain some selected air temperature that would otherwise not be achieved due to heat flows (heat loss) to the exterior environment.
A ventilating system (“V”) is intended to introduce air to or remove air from a space -- to move air without changing its temperature. Ventilating systems may be used to improve indoor air quality or to improve thermal comfort.
A cooling system ("C" is not explicitly included in the HVAC acronym) is designed to remove thermal energy from a space or building to maintain some selected air temperature that would otherwise not be achieved due to heat flows (heat gain) from interior heat sources and the exterior environment. Cooling systems are normally considered as part of the “AC” in HVAC; AC stands for air-conditioning.
HVAC Load Calculations
HVAC load calculation is very important to select the required capacity HVAC system for the desired location.
HVAC load calculations can be done manually using data book or software to get a required Cooling/heating load.
The software’s used for Heat Load calculations are – HAP software, E20 form, etc
Books used – ISHRAE fundamentals, ISHRAE Databook for HVAC
The procedure follows: -
The following procedure is according to ISHRAE.
1. Building Survey It includes the location and the building study which includes the building orientation, location (latitudes & longitude), windows, doors, roof and base construction, lighting, occupancy, direction of building and direction of doors and windows. The study of materials of each part of building is done. The area of the Space is noted to calculate the required CFM. 2. Heat Load Form from ISHRAE E20 form ISHRAE has a EXCEL sheet in which all the data to calculate heat is entered to get the heat load of the space with help of ISHRAE HVAC Data Book. 1st the Project name is entered followed by entering the area and height of space or directly the volume.
3. Outside Design Data
Now the Outside data is entered in the E20 form which includes location, latitude, longitude, daily range (Tmax-Tmin), Selecting the weather for design, DB temp and WB temp. The data for each location is given in the ISHRAE data book for HVAC.
4. Inside Design Data
The inside required conditions are entered which are the temperature and RH.
5. Outside Air per person (according to ASHRAE Std 62.1)
It is used to calculate the outside mixing air required for the space which can be calculated as: (CFM/person + CFM/ sq. ft.) – Exhaust.
6. Minimum Ventilation required in Breathing Zone
7. Net Outside Load
Outside Air + Infiltration = Net Outside Load
8. SHL (Sensible Heat Load)
It includes heat addition due to Radiation (Solar), Infiltration, Internal loads (people, lighting, equipment’s, energy carrying devices), heat due to AHU motor, etc.
9. ERSH (Effective Room Sensible Heat)
A safety factor of 5 to 8percent is taken to calculate ERSH.
10. Latent Heat Gain
It includes Latent heat gain due to People, Outside Air (bypass Air),equipment’s, Steam generating devices inside, etc. 11. ERLH (Effective Room Latent Heat) A safety factor of 5 to 8percent is taken to calculate ERLH.
12. Total heat
ERSH + ERLH + Ouside air heat = Total Load This total load is converted to BTU/sec to T.R. to get the required heat to be removed from the space.
13. SHF (Sensible Heat Fcator)
Sensible heat factor is calculated to get ADP (Apparatus dew point temp) to get the required coil temperature. After this we calculate Dehumidified air quantity get desired TR required to be removed from the space.
A sample E20 form to calculate heat load is shown below.
The Complete HVAC BIBLE for Beginners: The Most Practical & Updated Guide to Heating, Ventilation, and Air Conditioning Systems | Installation, Troubleshooting and Repair | Residential & Commercial
The Complete HVAC BIBLE for Beginners: The Most Practical & Updated Guide to Heating, Ventilation, and Air Conditioning Systems | Installation, Troubleshooting and Repair | Residential & Commercial
