An ideal gas refrigeration cycle using air as the working fluid operates between the pressure limits of 80 kPa and 240 kPa. Air is cooled to 40°C before entering the turbine. The lowest temperature of this cycle is

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Quizplus · Accepted Answer

Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 
k=1.4
P1= 80 "kPa"
P2=240 "kPa"
T3=40+273 "K"
"Mimimum temperature is the turbine exit temperature"
T4=T3*(P1/P2)^((k-1)/k) - 273
"Some Wrong Solutions with Common Mistakes:"
W1_Tmin = (T3-273)*(P1/P2)^((k-1)/k) "Using C instead of K"
W2_Tmin = T3*(P1/P2)^((k-1)) - 273 "Using wrong exponent"
W3_Tmin = T3*(P1/P2)^k - 273 "Using wrong exponent"

An Ideal Gas Refrigeration Cycle Using Air as the Working