Electrical & Electric

How a Refrigerator Works

All About Refrigeration

Introduction:

Most people think that the operation of refrigeration is just pure magic simply because they don’t understand the science of refrigeration. It really is not a lot different than air condition.

How a refrigerator works is depicted in the illustration below. On the left of the illustration shows what goes on inside the refrigerator. On the right of the illustration shows what goes on outside of the refrigerator on the outside back wall. 

1. The coolant (R-22) is a liquid as it enters the expansion valve (1). As it passes through, the sudden drop in pressure makes it expand, cool, and turn into a gas, just like a liquid aerosol turns into a cool gas when you spray it out of a can.

2. As the coolant flows around the chiller cabinet (2), usually around a pipe buried inside the back wall of the refrigerator, it absorbs and removes heat from the food inside.

3. The compressor (3) is really where the whole process begins. The compressor squeezes the coolant, raising its temperature and pressure. It's now a hot, high-pressure gas.

4. The coolant flows through thin pipes (4) on the back of the fridge, giving out its heat and cooling back into a liquid as it does so.

5. The coolant flows back (5) into the expansion valve (1) again and the cycle repeats itself. So heat is constantly picked up from inside the refrigerator and put down again outside.

Other than the controls mounted inside the refrigerator, which can be set manually to either colder or warmer, the entire process is automatic.  In summary the refrigerator keeps things cool by evaporating liquid gas to absorb heat. That is all there is to it and it really isn’t magic at all.

The fundamentals of refrigeration were worked out by William Cullen at the University of Glasgow in Scotland in 1756. He used a pump to create a partial vacuum over a container of diethyl ether which came to a boil, absorbing heat from the surrounding air. Further development and commercial application didn’t come about until the nineteenth century, primarily for shipping agricultural products across the United States.

Air conditioning works the same way except the expansion of the gas in the expansion valve for air conditioning is less than what is required for refrigeration. 

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About Side-by-Side Refrigerators

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