Question

Thermal efficiency of a heat engine is defined to be the ratio of energy output desirable to energy input. Would you think that efficiency is an appropriate definition to be used when a heat pump is being discussed? Why?

Answer 1

Answer:

No, it is no the same

Explanation:

In the heat engine, the machine receives heat to produce work, where we desire that the work produced is 100% of the heat received and giving the following expression:

$\eta=\frac{Q_{c}}{W}$

But in the heat pump, we receive work to produce heat and our desire is to convert all the work received into heat, which gives us the expression:

$\eta=\frac{W}{Q_{c}}$

Therefore the expressions are different.