In a DX air conditioning system, what can typically be said about the enthalpy of the outlet air compared to the inlet air?

In a direct expansion (DX) air conditioning system, the primary function is to remove heat and moisture from the air being treated. The system works by circulating refrigerant through a coil, where the refrigerant absorbs heat from the incoming air, thus cooling and dehumidifying it before it is circulated back into the conditioned space.

By the principles of thermodynamics, when air passes through the evaporator coil in a DX system, it typically loses heat and moisture. This heat removal translates into a decrease in enthalpy, which is a measure of total heat content in the air. Therefore, the air leaving the system (outlet air) will have a lower enthalpy compared to the air entering the system (inlet air).

This principle is fundamental to understanding how DX systems operate effectively. The reduction in enthalpy signifies that the air is not only cooler but also has reduced moisture content, which is essential for maintaining comfort levels and preventing humidity-related issues in the indoor environment.