True or false: The outlet air of a DX air conditioner is typically lower in enthalpy than the inlet air.

The statement is true because the primary function of a direct expansion (DX) air conditioning system is to remove heat and moisture from the air being circulated through the system. In such a system, the refrigerant absorbs heat from the indoor air as it evaporates, leading to a reduction in the air's temperature and humidity.

Enthalpy, which is a measure of the total heat content of the air, decreases as the air passes through a properly functioning DX air conditioning unit. The outlet air, being cooled and dehumidified, will have lower enthalpy compared to the warmer, more humid inlet air. This cooling process is essential for achieving comfort in indoor environments, and it demonstrates the efficiency of the DX system in conditioning the air effectively.

Other potential choices relate to conditions where enthalpy might not decrease, which are situations where the system may not be functioning correctly, but under normal operating conditions, the enthalpy of the outlet air is indeed lower.