Subtopic: Refrigeration and cold storage basics and applications
Question Statement:
In a vapor compression refrigeration system, subcooling the liquid refrigerant before the thermostatic expansion valve results in:
Options:
(A) An increase in the net refrigerating effect with no change in compressor work
(B) A decrease in the net refrigerating effect
(C) An increase in compressor work with no change in refrigerating effect
(D) A decrease in the COP of the system
Answer Key:
A
Step-by-Step Solution & Explanation
Subcooling lowers the enthalpy of the liquid entering the expansion valve ($h_3$), shifting state 4 to the left on a p-h diagram. This increases the refrigeration effect ($h_1 - h_4$) without altering the compressor suction/discharge states or work ($h_2 - h_1$), thus improving overall COP.