AC Systems – Basics of Load Calculation

commercial air cooling system in MOAmerican Services Cooling installation and repair in Saint Louis knows that the first step in A/C System design is to select indoor and outdoor summer and winter design conditions. Today, computer programs have been designed to provide very precise load determinations but an understanding of the process is required for anyone looking at a new system.

Computation of the peak cooling load. Heat gain is composed of or influenced by the conduction heat gain through opaque portions of the building’s skin; the conduction plus solar radiation through windows and skylights; the building internal loads such as people, lights, equipment, motors, appliances, and devices; and outdoor air load from infiltration. The heat gain is equal to the cooling load required.

Ventilation rates must also be considered in A/C cooling system design. Ventilation rates have typical values and fit into the equations. For example, bedrooms have a typical ventilation rate of 30 cubic feet per minute per room compared dressing rooms of only .5 cubic feet per minute per square foot.
Central air conditioning cooling systems are typically used where several spaces with uniform loads will be served by a single unit and where precision control of the rooms are required. Cooling coils can be direct expansions or chilled water. Within this type of a system there are multiple options for condensers, cooling towers, and ground-loop systems based on the specific application for the location.

Unitary air conditioning systems are typically limited to loads less than 100 tons. These systems are packed in self-contained or split configurations. Again depending on the specifics of your application each option will have benefits and drawbacks.