Question

A typical electric refrigerator has a power rating of 500 Watts, which is the rate (J/s) at which electrical energy is supplied to do work needed to remove heat from the refrigerator. If the refrigerator releases heat to the room at a rate of 800 Watts, at what rate (in Watts) does it remove heat from inside of the refrigerator?

Answer 1

Answer:

The rate of heat removed from inside the refrigerator is 300 watts.

Explanation:

By the First Law of Thermodynamics and the definition of a Refrigeration Cycle, we have the following formula to determine the rate of heat removed from inside the refrigerator ($\dot Q_{L}$), in watts:

$\dot Q_{L} = \dot Q_{H}-\dot W$ (1)

Where:

$\dot Q_{H}$ - Rate of heat released to the room, in watts.

$\dot W$ - Rate of electric energy needed by the refrigerator, in watts.

If we know that $\dot Q_{H} = 800\,W$ and $\dot W = 500\,W$, then the rate of heat removed from inside the refrigerator is:

$\dot Q_{L} = \dot Q_{H}-\dot W$

$\dot Q_{L} = 300\,W$

The rate of heat removed from inside the refrigerator is 300 watts.