Refrigerator: Concept of Chilling and Freezing

Refrigerator:

 a device used for cooling , or freezing the material inside it as per requirement.

basic principles and components of refrigerators at home

principle: a cold fluid medium is flown over or around the object to be cooled continously, due to temperature difference heat is transferred from the object to cold fluid

component: It has 4 main components: compressor, condenser, evaporator, and throttling device

Throttling device : it resist the flow of the gas and produce cold liquid (refrigerant). The throttling device restricts the flow, which causes a tremendous pressure drop. Due to the drop in pressure, the boiling point of the refrigerant is lowered, and it starts to evaporate. The heat required for evaporation comes from the refrigerant itself, so it loses heat, and its temperature drops

Evaporator: it is the compartment where the material to be cooled is kept, the cold liquid is flown in a heat exachanger as a result it absorbs heat thus it evaporates and convert into pure vapour.

Compressor: the vapour is at low pressure , so again to convert into liquid its pressur has to be increased therefore it is passed through compressor

Condensor: if pressure has increased therefore tempressure is also increased therefore it has to brought down to get cool liquid again so condensor is used,

This is fitted outside refrigerator to dissipiate heat to surrounding.

Refrigerant Used 

Commercial refrigerator and freezer units, which go by many other names, were in use for almost 40 years prior to the common home models. They used gas systems such asammonia (R-717) or sulfur dioxide (R-764), which occasionally leaked, making them unsafe for home use. Practical household refrigerators were introduced in 1915 and gained wider acceptance in the United States in the 1930s as prices fell and non-toxic, non-flammable synthetic refrigerants such as Freon-12 (R-12) were introduced. However, R-12 damaged the ozone layer, causing governments to issue a ban on its use in new refrigerators and air-conditioning systems in 1994. The less harmful replacement for R-12, R-134a (tetrafluoroethane), has been in common use since 1990, but R-12 is still found in many old systems today.