Question

The interior space of a building in winter is to be heated by a heat pump to maintain the internal temperature at 22.0°C. The 55.0 kW building heat load is to be provided by a heat pump that absorbs heat from a geothermal water source at 18.0°C. The water from the geothermal water source enters the evaporator heat exchanger at 18.0°C and exits at 11.00°C. The heat pump utilises refrigerant R-134a as the working fluid and operates with a discharge pressure of 1.40 MPa and a suction pressure of 320 kPa. Modelling the heat pump cycle as an actual vapour compression cycle (AVCC), with an evaporator exit temperature of 10.00°C and condenser entry and exit temperatures of 80°C and 30°C respectively, determine: What is the COP of this AVCC system? b. Determine mass flowrate of refrigerant (in kg/s). Find the required volumetric flowrate of water from the geothermal source (in L/min) d. Determine the isentropic efficiency of the compressor (assume the compressor to be adiabatic). e. If the heat pump were replaced by an ideal Carnot heat pump what would be the required power input to the heat pump? (Assume the heat load is still 55.0 kW).