Answer:
The magnitude of the heat transfer rate from the compressor is 87.05 kW
Explanation:
Initial pressure of refrigerant = 4 bar
Final pressure of refrigerant = 12 bar
From steam table,
Internal energy at 4 bar (U1) = 2554 kJ/kg
Internal energy at 12 bar (U2) = 2588 kJ/kg
Change in internal energy (∆U) = U2 - U1 = 2588 - 2554 = 34 kJ
Work input (W) = 120 kJ/kg
Quantity of heat transfer (Q) = ∆U + W = 34 + 120 = 154 kJ/kg
Volumetric flow rate of refrigerant = 8 m^3/min = 8/60 = 0.133 m^3/s
Density of refrigerant = 4.25 kg/m^3
Mass flow rate = density × volumetric flow rate = 4.25 kg/m^3 × 0.133 m^3/s = 0.56525 kg/s
Q = 154 kJ/kg × 0.56525 kg/s = 87.05 kJ/s = 87.05 kW
