DieselShip's Online Content Library

Q6. A vapour compression refrigeration plant uses ammonia and operates between saturation temperatures of -22°C and 30°C.

The refrigerant enters the compressor as dry saturated vapour and leaves at a temperature of 130°C. The liquid refrigerant enters the expansion valve at a temperature of 22°C. The cooking load is 200 kW.

The swept volume of the compressor is 0.0266 m³ with a volumetric efficiency of 90%.

(a) Sketch the cycle on pressure-specific enthalpy and Temperature-specific entropy diagrams. (4)

(b) Calculate EACH of the following:

(i) the compressor power; (5)

(ii) the coefficient of performance; (2)

(iii) the speed of the compressor. (5)