How does increased indoor SCFM affect the discharge pressure when measuring performance in cooling mode?

In cooling mode, the performance of an air-to-air heat pump is measured partially by evaluating the pressures within the system. Increased indoor SCFM (standard cubic feet per minute) refers to a higher airflow rate coming from the indoor coil. When the airflow increases, more latent heat is absorbed from the indoor environment, which enhances the system's ability to cool. This results in an increase in the pressure of the refrigerant within the system.

The discharge pressure is determined by the refrigerant's state and the compressor's operation. As more air flows across the evaporator coil, the refrigerant temperature drops, absorbing more heat. The compressor must work harder to move this refrigerant, raising the discharge pressure due to the compressor's increased workload and the resultant thermal dynamics within the system.

Higher discharge pressure is indicative of the higher energy requirement necessitated by the increased volume of refrigerant being circulated and conditioned and the additional thermal load being placed on the system. Therefore, increased indoor SCFM directly contributes to an increase in discharge pressure during cooling operation.