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Q6. A vapour compression refrigeration plant is used to produce ice at  from fresh water at .

The R134a refrigerant is compressed in an isentropic process from suction conditions of 1.3272 bar,  to discharge pressure of 10.163 bar.

The temperature rise of the condenser fresh water cooling is 10 K at a flow rate of 22 tonne/hour. The refrigerant enters the expansion valve at a temperature of

(a) Sketch the cycle on Pressure-specific enthalpy and Temperature-specific entropy diagrams. (2)

(b) Calculate EACH of the following:

(i) The compressor discharge temperature;(4)

(ii) The mass flow rate of refrigerant required;(5)

(iii) The rate of ice production in tonne per hour. (5)

Note: for fresh water C = 4.2 kJ/kg K

For ice C = 2.1 kJ/kg K, enthalpy of fusion = 335 kJ/kg.