TABLE OF CONTENTS Internal sources of heat energy may contribute significantly to the total heat gain for a space. In the case of a completely isolated interior room, the total heat gain is due entirely to internal sources. These internal sources fall into the general categories of people, lights, and equipment such as cooking appliances, hospital equipment, office equipment, and powered machinery.
Failure to identify all internal heat sources can lead to gross undersizing, while an overly conservative approach may lead to significant oversizing. Both cases are undesirable.
The most serious problem in making accurate estimates of internal heat gain is lack of information on the exact schedule of occupancy, light usage, and equipment operation. For example, it may not be reasonable to assume that all the occupants are present, all lights on, and all equipment operating in a large office building. However, for a particular room in the building, the total occupancy, light, and equipment load usually should be used to compute the room's heat gain. In brief, it is probable that any particular room will be fully loaded but the complete building will never experience a full internal load. The assumption here is that the air cooling and delivery systems would be sized to accommodate the space loads, but the central cooling plant would be sized for a lower capacity based on the diversified load. Every building must be examined using available information, experience, and judgment to determine the internal load diversity and schedule.
The heat gain from...
