An air conditioner running with R-134a on a cycle executed under the saturation dome between the pressure limits of 0.8 MPa and 0.12 MPa. The maximum Coefficient of Performance of this heat pump is

Question

Quizplus · Accepted Answer

Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 
PH=800 "kPa"
PL=120 "kPa"
TH=TEMPERATURE(R134a,x=0,P=PH) "C"
TL=TEMPERATURE(R134a,x=0,P=PL) "C"
COP_R=(TL+273)/(TH-TL)
"Some Wrong Solutions with Common Mistakes:"
W1_COP=PL/(PH-PL) "Using pressures"
W2_COP=TL/(TH-TL) "Using temperatures in C" 
W3_COP=TH/(TH-TL) "Heat pump COP, with temperatures in C"
W4_COP=(TH+273)/(TH-TL) "Heat Pump COP, with temperatures in K"

An Air Conditioner Running with R-134a on a Cycle Executed