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M9501
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Homework Statement
The electrical energy supplied to a heater can be turned with 100% efficiency into thermal energy (room heating).Assume you use a heat pump with a COP of 4 instead to reach the same temperature
increase in the room.How much electrical energy will you save ?
Homework Equations
COP(heating)=Qh/W=Qc+W/W;
The Attempt at a Solution
Firstly i thought about getting the percentage of energy used which is equal to the work and then getting the percentage of energy saved by subtraction (100%-%ofUsedEnergy).
since temperature is constant then Qh is constant(am i correct?)
W=1/4 Qh (i guess something is wrong here)
∴the percentage of energy used=100*1/4=25%
∴the percentage of energy saved=75%