Subtopic: Refrigeration and cold storage basics and applications
Question Statement:
The throttling process across the expansion valve in a vapor compression refrigeration cycle is thermodynamically modeled as an:
Options:
(A) Isenthalpic process (constant enthalpy)
(B) Isentropic process (constant entropy)
(C) Isothermal process (constant temperature)
(D) Isobaric process (constant pressure)
Answer Key:
A
Step-by-Step Solution & Explanation
Throttling through a narrow orifice or thermostatic expansion valve involves rapid expansion with no work interaction ($W = 0$) and negligible heat exchange ($Q = 0$). By the first law of thermodynamics, it is isenthalpic: $h_1 = h_2$.