Which equation is used to calculate the actual operating capacity of a system?

The equation used to calculate the actual operating capacity of a system in refrigeration and air conditioning is based on the airflow (cfm, or cubic feet per minute), the heat transfer per change in temperature (delta H), and the specific heat of air. The correct equation employs the factor of 4.5, which is derived from the specific heat of air and the density of air under standard conditions.

This factor takes into account the conversion of cfm to BTUH, the units of measurement, and the heat change of the air as it moves through the system. When using 4.5, the equation effectively calculates the cooling or heating capacity in BTUs per hour (BTUH), reflecting how much heat is being removed or added to the air in the system.

Using this equation allows technicians to assess the performance of the HVAC system accurately, ensuring that the system is operating within its designed capacity to ensure efficiency and effectiveness.