Question

A residential heat pump has a coefficient of performance of 1.49 How much heating effect, in kJ/h, will result when 4 kW is supplied to this heat pump?

Answer 1

Answer:

21.456 kJ/h

Explanation:

See the figure attached. In this case  

$W_{cycle} = 4 kW$

$Q_{out} = \text{heating effect}$

Coefficient of performance in heat pump is defined by

$COP = \frac{Q_{out}}{W_{cycle}}$

$Q_{out} =COP*W_{cycle}$

$Q_{out} =1.49*4 \, W$

$Q_{out} = 5.96 \, W$

Now it is necessary to change units, remember that Watt (W) is defined as J/s

$Q_{out} = 5.96 \frac{J}{s} \frac{3600s}{1 h} \frac{1 kJ}{1000 J}$

$Q_{out} = 21.456 \frac{kJ}{h}$