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Q6. A vapour compression refrigerant plant uses R134a and operates between saturation temperatures of -20℃ and 40℃. The refrigerant leaves the evaporator at -10℃ and leaves the compressor at 60oC.

The heat removed in the condenser is 199.63 kJ/kg of refrigerant flowing and the cooling load is 60 MJ/hour.

(a) Sketch The cycle on Pressure-specific enthalpy and Temperature-specific entropy diagrams. (4)

(b) Calculate EACH of the following:

(i) The degree of undercooling in the condenser; (4)

(ii) The mass flow rate of liquid refrigerant entering the evaporator; (6)

(iii) The coefficient of performance. (2)