Question

To make ice, a freezer that is a reverse Carnot engine extracts 37 kJ as heat at -17°C during each cycle, with coefficient of performance 5.8. The room temperature is 26.9°C. How much (a) energy per cycle is delivered as heat to the room and (b) work per cycle is required to run the freezer?

Answer 1

a) 6.4 kJ

b) 43.4 kJ

Step-by-step explanation:

a)

`Q_(a)` = Heat absorbed = 37 kJ

`β` = Coefficient of performance = 5.8

`W` = Work done

Heat absorbed is given as

`Q_(a)` =
`β`
`W`

37 = (5.8)
`W`

`W` = 6.4 kJ

b)

`Q` = work per cycle required

`Q` =
`Q_(a)` +
`W`

`Q` = 37 + 6.4

`Q` = 43.4 kJ