DieselShip's Online Content Library

Q6. A vapour compression refrigeration system operates between the pressures of 1.447 bar and 10.99 bar. The ammonia refrigerant enters the compressor as a dry saturated vapour and is compressed with an isentropic efficiency of 93.9 %. The compressor has swept volume of 1.79 m3/s and a volumetric efficiency of 90 %.

The refrigerant enters the expansion valve at a temperature of 24℃.

(a) Sketch The cycle on pressure-specific enthalpy and Temperature-specific entropy diagrams. (2)

(b) Calculate EACH of the following:

(i) The temperature of the refrigerant at the compressor discharge; (5)

(ii) The heat removed in the condenser; (4)

(iii) The compressor power; (3)

(iv) The coefficient of performance when operating as a heat pump. (2)