Do you know how do refrigerator systems work? Or how it works?

How Does a Refrigerator Work Thermodynamics

What is a refrigerator?

A refrigerator is a household appliance which is delivered a cool temperature than the external environment. It makes the object cooler than the normal temperature. The cold temperature slows down the bacterial growth in food and it preserves the food for a longer period. So why we use a refrigerator? We use a fridge for keeping fresh food, outside of bacteria.

Who invented the refrigerator? Oliver Evans invented the refrigerator design. Then US physician John Gorrie built the refrigerator in 1844.

Application of Thermodynamics in Refrigerator

There are four laws of thermodynamics. The law describes the relationships between thermal energy, heat and other form of energy affects matter. Why did we talk about thermodynamics? Because the refrigerator is formed by the second law of thermodynamics. The second law of thermodynamics is talked about the quality of energy. It states that the energy is transferred or transformed, more and more of it is wasted. It also states that there is a natural tendency of any isolated systems to degenerate into a more disordered state.

If we place the cold object into the hot object, the cold object becomes warmer and the hot object becomes cooler.

Refrigerator Components

  1. Expansion Valve
  2. Compressor
  3. Evaporator
  4. Condenser
  5. Refrigerant ( a specialized gas)

Generally, the refrigerator (a specialized gas) is used for the vapor compressor cycle. It used CFC gas (chlorofluorocarbon). But CFC affects the ozone layer and it affects the environment critically. Nowadays HFC-134a or ammonia gas are used for a refrigerator gas. It is also called tetrafluoroethane.

Refrigerator working principle

A refrigerator works on the vapor compression refrigeration cycle. There are four parts (Expansion Valve, compressor, evaporator, condenser) and all are connected with copper or steel tubes. The refrigerator has a low boiling point -20-degree celsius. The freezer is surrounded by the evaporator tube. When we keep something on the refrigerator, the evaporator tube absorbs the heat from the object. Then the liquid refrigerant is converted into vapor.

How Does a Refrigerator Work Thermodynamics

The vapor is compressed by the compressor to high pressure and temperature. The heat is rejected to the atmosphere from the compressor from vapor to liquid. It passes through the expansion valve and moves to the evaporator, The cycle is repeated. It cools down the air inside the fridge.

So we can find out the process:

Step-1: At first, the refrigerant is compressed by compressor until high temperature and it flows throw the coils and releases the gas out.

Step-2: The hot gas becomes the liquid when they meet.

Step-3: The liquid is forced through the expansion valve and it cools down the fridge by absorbing heat from the refrigerator.

Step-4: The refrigerant evaporates to gas and flows back to the compressor and it’s over and over again.


Refrigerator and air conditioner work the same principle of cooling through evaporation.