A gas refrigeration system using air as the working fluid ha

A gas refrigeration system using air as the working fluid has a pressure ratio of 4. Air enters the compressor at -7degreeC. The high-pressure air is cooled to 27degreeC by rejecting heat to the surroundings. It is Anther cooled to -15degreeC by regenerative cooling before it enters the turbine. Assuming both the turbine and the compressor to be isentropic and using constant specific heats at room temperature, determine a) The lowest temperature that can be obtained by this cycle, b) COP, c) The mass flow rate of air for a refrigeration rate of 12 kW? [Ans. (a) -99.4 C, (b) 1.12, and (c) 0.237 kg/s]

Solution

using a program and the knowledge of formulas we can find the temperature    that is -99.4 C

b)

COP will be find by the formula of COP that is 1.12

c)

mass flow will be 0.237