Question

Refrigerant-134a enters an adiabatic compressor at -30oC as a saturated vapor at a rate of 0.45 m3 /min and leaves at 900 kPa and 55oC. Determine (a) the power input to the compressor, (b) the isentropic efficiency of the compressor, and (c) the rate of exergy destruction and the second-law efficiency of the compressor. Take T0

Answer 1

Answer:

a) 1.918 kw

b) 86.23%

c) 0.26 kw

Explanation:

Given data:

T1 = -30°C = 243 k  , T0 = 27°C

using steam tables

h1 = 232.19 KJ/kg

s1 = 0.9559 Kj/Kgk

T2 = 55°C   P2 = 900 kPa

Psat = 1492 kPa,  h2 = 289.95 Kj/Kg, s2 = 0.9819 Kj/kgk , m = 0.0332 kg/s

a) Determine the power input to the compressor

power input = 1.918 kw

b) Determine isentropic efficiency of compressor

Isentropic efficiency = 86.23%

c) Determine rate of exergy destruction

rate = 0.26 kw

Attached below is the detailed solution of the given problems