The performance of the vapour compression refrigerator varies considerably with both vaporising and condensing temperatures.

In vapour compression cycle, the useful part of the heat transfer is at the condenser.

In ammonia-hydrogen (electolux) refrigerator, no compressor, pump or fan is required.

The effect of under-cooling the liquid refrigerant is to decrease the coefficient of performance.

dehumidification

cooling and humidification

cooling and dehumidification

dehumidification and pure sensible cooling

remains constant

increases

decreases

none of these

(T1)/(T2-T1)

(T2-T1)/(T1)

(T1-T2)/(T1)

(T2)/(T2-T1)

raise the pressure of the refrigerant

raise the temperature of the refrigerant

circulate the refrigerant through the refrigerating system

all of the above