ESCO Air Conditioning Practice Exam

In an air conditioning system that uses a thermostatic expansion valve, the temperature of the evaporator outlet will usually be

1. Cooler than the evaporator inlet

2. Equal to the evaporator inlet

3. Unchanged

4. Warmer than the evaporator inlet

The correct answer is: Cooler than the evaporator inlet

The temperature of the evaporator outlet will usually be cooler than the evaporator inlet because the thermostatic expansion valve serves to regulate the flow of refrigerant into the evaporator coils based on the temperature in the evaporator. As the refrigerant flows through the evaporator, it absorbs heat from the air, causing the temperature of the refrigerant to decrease. This cooled refrigerant then exits the evaporator and enters the expansion valve, where it is allowed to expand and cool further before entering the compressor. This process results in the outlet temperature being cooler than the inlet temperature. The other options are incorrect because they do not take into consideration the cooling effect of the expansion valve on the refrigerant before it exits the evaporator.