Process of Heat Load Calculations
The heat load calculations are a highly specialized, time consuming and complicated task of the HVAC designers. It is also very important task since it is only based on the heat load calculations that the HVAC designer can recommend air-conditioning system of proper type and size for the various applications like hall, auditorium, theater, cinema hall, air-port etc.
There are two major steps of heat load calculations: survey of the building and the actual heat load calculations, let us see both these steps:
1) Surveying of the building: The building which is to be air-conditioned is surveyed thoroughly and various measurements are carried out. The HVAC designer goes to each and every room of the building that is to be air-conditioned. They take measurement of all the walls of the room, roof of the room and windows of the room. They also find out the direction of walls, and windows of the rooms.
With regards to the roof, the HVAC designer finds out if there is any other room above the roof of the room or if it is exposed directly to the sun. Regarding the windows the HVAC designer finds out the type of window and type of the curtain fitted on it and the presence of awnings if any. The HVAC designer also tries to find out if there are any insulation applied to the walls and the roof of the room.
Apart from this, the HVAC designer finds out the maximum number of persons that will be present inside the room. They will also trace out the presence of any electrical and electronic appliances inside the room. They will also find all other sources of heat inside the rooms of the building.
This survey is carried out for all the rooms of the building no matter how small or large they are. Usually the smaller rooms will take lesser time for survey, while the large rooms required more time mainly due to presence of variety of source of heat in the large rooms.
Overall, the process of carrying out the survey of the building for heat load calculations is very lengthy and time consuming. Sometimes merely the survey may take days to complete. In modern days the survey of the rooms of the building can also be carried by studying the drawings of the building. It may not be necessary to physically go to the site and carry out various measurements. In the building drawings all the dimensions of the rooms are available at hand. The HVAC designer merely has to find out the various sources of heat inside the room.