An ideal gas refrigeration cycle with three stages of compression with interstage cooling using N2 as the working fluid. N2 is an ideal gas with CP = 1 kJ/Kg, k = 1.4. All the compressors and turbine can be assumed reversible. P1=100kpa, T1=240K, P2=500kpa, P4=2.5 MPa, P6=12.5MPa

i) Calculate the compressor work for each stage and the turbine work assuming T₃ = T₅ = T₇ = 240 K

ii)Calculate the temperatures T2, T4, T6 and T8

iii)Calculate the heat loads QH,1 QH,2 QH,3 on the interstage coolers if T3 = T5 = T7 = 240 K

IV) Calculate the COP of this ideal refrigeration cycle.

b) Repeat parts i-IV by assuming that the efficiency of all the compressors and turbines is 0.7