Calculating Net Power for a Heat Pump Cycle

[eku_girl83]

Here's my problem:
A heat pump cycle whose coefficient of performance is 2.5 delivers energy by heat transfer to a dwelling at a rate of 20 kW.
a) Determine the net power required to operate the heat pump, in kW.
b) Evaluating electricity at 8 cents per kWh, determine the cost of electricity in a month when the heat pump operates for 200 hours.

I know that the coefficient of performance = Qout/Wcycle = Qout/(Qout-Qin).
But what is meant by net power? And more importantly, how do I calculate it?

Thanks for help in advance,
eku_girl83

 

[russ_watters]

Power to operate the heat pump is Qin.

 

[CharlesP]

Here's my problem:
A heat pump cycle whose coefficient of performance is 2.5 delivers energy by heat transfer to a dwelling at a rate of 20 kW.

a) Determine the net power required to operate the heat pump, in kW.
20 kw/2.5 = electrical power input = 8 kw This must be the "net power."
That is about typical for a freon based heat pump. I got one.

b) Evaluating electricity at 8 cents per kWh, determine the cost of electricity in a month when the heat pump operates for 200 hours.
8 kw x 200 hr = 1600 kwh. 1600 kwh x .08 $/kwh = $128.00
Looks like a typical bill to me. But natural gas is cheaper.

I know that the coefficient of performance = Qout/Wcycle = Qout/(Qout-Qin).
But what is meant by net power? And more importantly, how do I calculate it?