(Solved): A vapour-compression system having Freon 12 as the working fluid is to be used as a heat pump to e ...

A vapour-compression system having Freon 12 as the working fluid is to be used as a heat pump to extract 23.5 kW from the ambient air outside a house at a temperature of

in order to transfer it to the air circulating inside of the house at

. There is a difference of

between the evaporator temperature and the outside air temperature as well as a difference of

between the condenser temperature and the inside air temperature. For the purposes of the analysis, assume that the vapour entering the compressor is saturated, that the efficiency of the compression process is

and that the liquid at the inlet of the expansion valve is saturated. Determine the coefficient of performance and the saving to be realized from the use of the heat pump if electricity is available at 4.5 cents per kilowatt hour.