Using Isothermally Compressed Air to Cool a Refrigerator

[Andy049]

If I have a steady supply of isothermally compressed air at 7 psi (approximately 148 kPa) at a temperature of 4 degrees C, how would I calculate the amount needed of that air per unit time to maintain the temperature of a 14 cf refrigerator at 3 degrees C? A 18 cf freezer at -18 degrees C?

 

[Chestermiller]

The first step would be to determine the temperature that the air would attain if it were expanded adiabatically and reversibly from a pressure of 7 psig to a pressure of 0 psig.