Solved Problem 6.5 - Adiabatic Efficiency of a R134a Compressor

Consider the R134a refrigerator compressor shown below.

• a. Carefully plot the actual and isentropic compression processes on the h-s diagram and indicate the actual and isentropic specific work done to drive the compressor on the plot.
• b. Using R134a refrigerant tables determine the specific work required to drive the compressor [53.9 kJ/kg].
• c. Using R134a refrigerant tables determine the adiabatic efficiency of the compressor [C = 92%].
• d. Discuss these results and determine if this is a feasible compressor design.

Derive all equations used starting from the basic energy equation for a flow system and the equation for adiabatic efficiency of a compressor.

Solution Approach:

Discussion: This is a feasible compressor design - the adiabatic efficiency is higher than we expected however within an acceptable range (less than around 95%),