A heat pump cycle whose coefficient of performance is 24 del

A heat pump cycle whose coefficient of performance is 2.4 delivers energy by heat transfer to a dwelling at a rate of 18 kW. Determine the net power required to operate the heat pump, in kW.

Solution

A heat pump is a device which applies external work to extract an amount of heat Q_C from a cold reservoir and delivers heat Q_H to a hot reservoir. A heat pump is subject to the same limitations from the second law of thermodynamics as any other heat engine and therefore a maximum efficiency can be calculated from the Carnot cycle. Heat Pumps are usually characterized by a coefficient of performance which is the number of units of energy delivered to the hot reservoir per unit work input.

Coefficient of Performance = Q_{H/ W}

_{= 18/ 2.4}

   _{= 7.5 KW}

_{So the net power required to operate the Heat Pump is 7.5 KW.}