What does "enthalpy" refer to in HVAC systems?

Enthalpy in HVAC systems refers to the total heat content of air. It encompasses not only the sensible heat, which affects temperature, but also the latent heat, which is associated with moisture content in the air. This total heat content is crucial for understanding how air interacts with heating and cooling systems, particularly in the context of energy transfer and thermal comfort.

When calculating the efficiency of HVAC systems, knowing the enthalpy helps in managing energy use and ensuring optimal performance. Systems are often designed to alter the enthalpy of air to maintain desired indoor conditions, making it an essential concept in both heating and cooling processes in HVAC applications.

While airflow resistance, refrigerant pressure, and humidity level are all important factors in HVAC systems, they are not synonymous with enthalpy, which specifically measures the combined heat content of the air.