How does a refrigeration compressor work?

How does my refrigeration compressor work?

Have you ever wondered how your air conditioning unit keeps the air of your home cool? It seems like you are not the only one wondering about this rather genius invention that makes warm summer days so much more pleasant. When you look for cooling systems on the world wide web you will find something called a refrigeration compressor. Lets find out how this thing called “refrigeration compressor” works.

The process of refrigeration

The refrigeration compressor uses a liquid refrigerant as a medium, which circulates, absorbs and removes heat from the space to be cooled. By doing so it rejects the heat elsewhere. A typical single stage refrigeration compression system has four components: a compressor, a condenser, a thermal expansion valve (also called a throttle valve) and an evaporator. As the circulating refrigerant enters the compressor in a thermodynamic state known as saturated vapor, is being compressed to a higher pressure, resulting in a higher temperature. Because of the saturated vapor, this system is also called as a vapor- compression refrigeration. The hot, compressed vapor is then in the thermodynamic state known as a superheated vapor and it is at a temperature and pressure at which it can be condensed with either cooling water or cooling air. That hot vapor is routed through a condenser where it is cooled and condensed into a liquid by flowing through a coil or tubes with cool water or cool air flowing across the coil or tubes. This is where the circulating refrigerant rejects heat from the system and the rejected heat is carried away by either the water or air (whichever may be the case).

The condensed liquid refrigerant, in the thermodynamic state known as a saturated liquid, is next routed through an expansion valve where it undergoes an abrupt reduction in pressure. That pressure reduction results in the adiabatic flash evaporation of a part of the liquid refrigerant. The auto-refrigeration effect of the adiabatic flash evaporation lowers the temperature of the liquid and vapor refrigerant mixture to where it is colder than the temperature of the enclosed space to be refrigerated.

The cold mixture is then routed through the coil or tubes in the evaporator. A fan circulates the warm air in the enclosed space across the coil or tubes carrying the cold refrigerant liquid and vapor mixture. That warm air evaporates the liquid part of the cold refrigerant mixture. At the same time, the circulating air is cooled and thus lowers the temperature of the enclosed space to the desired temperature. The evaporator is where the circulating refrigerant absorbs and removes heat, which is subsequently rejected in the condenser and transferred elsewhere by the water or air used in the condenser.
To complete the refrigeration cycle, the refrigerant vapor from the evaporator is again a saturated vapor and is routed back into the compressor.

Similar compressor systems

The most common compressor in chillers is called reciprocating compressor. These compressors are found either open, hermetic or semi- hermetic. The compressor is called a hermetic motor or hermetic compressor if the compressor and the motor driving the compressor is integrated within the refrigeration compression unit. In an open system the motor driving refrigeration compressor is outside of the refrigeration system.

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