How a Mechanical Refrigerator works

In order to understand the operation of the mechanical refrigerator, it is significant to understand the physical substances used to extract heat. A brief study of the elementary physics involved is provided in this chapter, in order that all explanations may be made clear.

The operation of a modern mechanical refrigerator (removing heat from inside the refrigerator) might be compared to removing water from inside a leaking canoe. In removing water from the canoe a sponge is used to sop up the water. The sponge is held over the side, squeezed, and the water is deposited overboard. The operation may be repeated as often as necessary.

In this operation, water is transferred from inside the canoe back into the lake. 

In a refrigerator, heat is transferred instead of water. Heat leaks into a refrigerator through the insulation and enters when and the door is opened. Inside the refrigerator heat is absorbed, “sopped up,” by the liquid refrigerant in the cooling unit (evaporator) as insolate in Fig. 1.1.

The refrigerant in absorbing heat changes from a liquid to a gas point after the refrigerant has absorbed heat and turned to a gas, it is pumped outside the refrigerator. It is then compressed and the heat is “squeezed” out by being subjected to high pressure and cooled in a condenser. The refrigerant continues to flow through the refrigerating cycle absorbing heat inside the refrigerator until the desired refrigerating temperature is reached and the action stops. Heat is not destroyed to make the refrigerator cold; it is simply removed from the refrigerated space and released outside the cabinet.

The paragraphs in this chapter which follow will give you the foundation needed to understand and describe the heat removal operation in a more technical way. In arithmetic problems that follow these basics, sighs are used:

+    means plus or add

-     means minus or subtract

x    means multiply or times

( )   means brackets, do the arithmetic inside the brackets first.    

=    means equals.

(4)2           means the number inside of the bracket is multiplied by itself by the number of times indicated (squared). The indicator number is called the exponent. Example 4 2 means 4 x 4 = 16.

Service managers of refrigerator companies prefer to service and installation mechanics who are well-grounded in the essential principles of physics as it pertains to refrigeration.