Chapter 5, Problem 42R

To determine

To order: The complete event that place in a refrigerator for removal of thermal energy from a body and also to draw the complete cycle.

Explanation of Solution

Introduction:

A refrigerator is a device which transfers thermal energy from a cool surroundings to a hotter one. It works on the second law of thermodynamics. The energy to do so is obtained from the electrical source through an electrical outlet.

A refrigerator contains an expansion valve through which the liquid coolant is pumped in where it changes to a gas and expands in the surroundings doing some work on it. By doing this, the coolant transfers thermal energy to its surroundings and cools down after which it is again pushed in into the refrigerator through pipes where it absorbs the heat from our food making the refrigerator cool.

This coolant gas is then compressed by the compressor which makes it warmer than the temperature of the room. The warm gas is pumped out through the condenser coils, the thermal energy of which spreads into the whole room. As a result of this, the room gets heated and converts the gas into liquid after which it enters the expansion valve again repeating the whole process again.

  

Conclusion:

Hence, the refrigerator works basically to cool our food by removing thermal energy from it with the help of liquid coolant, expansion valve and the compressor.