In a vapour compression refrigeration cycle, the refrigerant enters the compressor in saturated vapour state at evaporator pressure, with specific enthalpy equal to 250 kJ/kg. The exit of the compressor is superheated at condenser pressure with specific enthalpy equal to 300 kJ/kg. At the condenser exit, the refrigerant is throttled to the evaporator pressure. The coefficient of performance (COP) of the cycle is 3. If the specific enthalpy of the saturated liquid at evaporator pressure is 50 kJ/kg, then the dryness fraction of the refrigerant at entry to evaporator is ________.
0.25
Compressor work is 300 − 250 = 50 kJ/kg. A COP of 3 gives refrigeration effect 150 kJ/kg, so evaporator-inlet enthalpy is 250 − 150 = 100 kJ/kg. At evaporator pressure, \(h_{fg}=250-50=200\ \mathrm{kJ/kg}\). Thus \(x=(100-50)/200=0.25\).
Important Questions from Vapour Compression (V-C) Cycle
A refrigeration plant works on an ideal vapour-compression refrigeration cycle with refrigerant as R-12 and develops a refrigeration capacity of 10 TR. If the refrigeration effect produced is 100 kJ/kg, what will be the mass flow rate of the refrigerant? [Assuming, 1 TR = 3.5 kW]
In vapour compression refrigeration system, the effect of liquid refrigerant under cooling is to
If vapour is NOT superheated after compression, it is called ________.
The amount of heat removed in the evaporator per unit mass flow of refrigerant is called:
In a vapor compression system, the highest temperature of the refrigerant during the cycle occurs after
