A cascade refrigeration system is used to provide a steady rate (Q1) of low-temperature cooling for a deep freezer maintained at -75°C. Propane is the working fluid for the low-temperature cycle which operates at evaporator and condenser pressures of P1 and P2 respectively. R-134a is the working fluid for the high-temperature cycle which operates at a condenser pressures of P6. Both cycles operate as ideal vapor-compression refrigeration cycles. An intermediate temperature heat exchanger with a 10°C minimum temperature difference between working fluids serves as the evaporator for R-134a and the condenser for propane. Propane System Evaporator Pressure: P1 (bar) = 0.05

Propane System Condenser Pressure: P2 (bar) = 3

R-134a System Condenser Pressure: P6 (bar) = 12

Cooling Capacity: Q1 (kW) = 3.4

Required:

a. Determine the compressor inlet temperature (C) for the propane cycle.

b. Determine the compressor inlet enthalpy (kJ/kg) for