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A refrigeration cycle uses the "refrigerant X" fluid. This fluid's thermodynamic properties can be found on the pressure-enthalpy chart provided. The cycle runs between the two pressures 1.2 bar for

the evaporator and 12 bar for the condenser. At the exit from the evaporator the fluid is saturated vapour. At the exit of the condenser the fluid is a sub cooled liquid at 40°C The compressor has an adiabatic efficiency of 76%. Sketch a hardware diagram for the refrigeration system. Draw the whole cycle on the Refrigerant X pressure-enthalpy chart provided. Label the stations around the cycle starting at (1) for the compressor inlet.[2 marks] Calculate the "specific refrigerating effect" i.e. the heat extraction in the evaporator per kg of fluid passing through.[2 marks] Calculate the compressor specific work input. Calculate the Coefficient of Performance of the cycle. In the winter when the average outside temperature is 0°C a house is heated to 20°C using a heat pump. This heat pump uses "Refrigerant X" as the working fluid. The heat pump cycle operates between the saturation temperatures of -5°C and +55°C. Station (1) is the inlet to the compressor the refrigerant is super heated by 20°C. The compressor has an isentropic efficiency of 85%. At exit from the condenser the refrigerant is liquid and sub-cooled by 5°C. Draw a hardware diagram. Show the main components. Include station labels starting with compressor inlet as (1). Plot the cycle on the "Refrigerant X" pressure v's enthalpy chart provided and find the enthalpy at each station.[4 marks] Evaluate the "Coefficient of Performance" of the cycle. Compare this result to an ideal reversible heat pump operating between 0°C and20°C.(2 marks]

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