In a vapour compression refrigeration system, throttle value is used in place of an expander because
Option (A)
It considerably reduces the system weight
Option (B)
it improves the COP, as the condenser is small
The positive work in isentropic expansion of liquid is very small
It leads to significant cost reduction
Correct Option:
Question Solution:
Flow work = ∫-vdp
For liquid vL is very small; so work obtained in expanding has no advantage
Secondly, the frictional and thermodynamic losses in expanding the liquid will make the gain work negative
So isentropic process of expansion is replaced by isenthalpic process through throttling