Heat Pump

swain1

1. The problem statement, all variables and given/known data
It is proposed to heat a house using a heat pump operating between the house (27 degees) and the outside (-13 degrees). The heat loss from the house is 7kW. What is the minimum power required to operate the heat pump?


2. Relevant equations



3. The attempt at a solution
e=Th/(Th-Tc) =7.5
W=7000/7.5 =933 W

Just checking if this is correct or have I made a mistake. Thanks

OlderDan

Since you start out with a dimensionless number, a ratio of temperatures, and equate that to some number of Watts, something is surely wrong. Maybe you just need to rewrite things to make it clear

swain1

I have moved the equation now. If you look at the question you will see that 7000 has units of watts. Is it wrong anyway?

OlderDan

That looks better. It woudl be better still if you had units of W on the 7000.