Refrigerator : Introduction, Components, Working and its Application

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Refrigerator 

A refrigerator is a machine for keeping things cold. Fridge or an icebox is a example of refrigerator.
A refrigerator does not cool items by lowering their originals temperatures ; instead , an evaporating gas called a refrigerant draw heat away, leaving the surrounding area much colder. Refrigerator and air conditioners both work on the principle of cooling through evaporator.

A refrigerator is consists of a thermally insulated compartment and also a heat pump that transfer the heat from the inside of the fridge to its external environment so that the inside of the fridge is cooled to a temperature bellow the room temperature.

a refrigerator maintain a temperature a few degree above the freezing point of the water. optimum temperature rang for food storage is 3 to 5 degree C. A similar device that maintains a temperature below the freezing point of water is called freezer. The refrigerator replace the icebox, which had been a common household appliance for almost a century and a half.

The first cooling system for food involved ice, artificial refrigeration began in the mid of 1750, and it was developed in the early 1800.
The first vapor compression refrigeration system was built in 1834. and the first commercial ice making machine was invented in 1854.
Refrigerator for home use were invented in 1913.

Components of the Refrigerator 

A refrigerator consists of the following main parts that play the vital role in the refrigeration process.
1. Expansion valve :
It is a very small device which control the flow of the liquid refrigerant into the evaporator.
2. Compressor :
The compressor consists of a motor that sucks in the refrigerant from the evaporator and compress it in a cylinder to make hot , high pressure gas.
3. Evaporator :
this is the part that actually cools the stuff kept inside a refrigerator. it consists of the finned tubes that absorb heat blow through  a coil by a fan. the evaporator absorbed heat from the stuff kept inside , and as a result of this heat, the liquid refrigerant turns into vapor.
4. Condenser :
It consists of the coiled set of the tubes with externals fins and is located at the rear of the refrigerator. It helps in the liquefaction of the gaseous refrigerant by absorbing its heat and subsequently expelling into the surroundings. As the heat of the refrigerant is removed , its temperature drop to condensation temperature , and it changes its state from vapor to liquid.
5. Refrigerant:
It is known as the coolant. It it the liquid that keeps the refrigeration cycle going. It's actually a specially designed chemical that is capable of alternating between being a hot gas and a cool liquid.

Working of a Refrigerator 

The refrigerant which is in liquid form passes through the expansion valve and turns into a cool gas due to the sudden drop in pressure. As the cool refrigerant gas flow through the chiller cabinet, it absorbs the heat from the food items inside the fridge. The refrigerant , which is now gas flow into the compressor , which sucks it inside and compresses the molecules together to make into a hot, high pressure gas.


Now, this gas transports to the condenser coils located at the back of the fridge,where the coil helps dissipate its its heat so that it becomes cool enough to condense and converted back into its liquid phase. Because the heat collected from the food items is given off to the surroundings via the condenser, it feels hot to the touch.
After the condenser the liquid refrigerant travel back to the expansion valve, where it experiences a pressure drop and once again becomes a cool gas. It then absorbs heat from the contents of the fridge and the hole cycle repeats itself.

Applications :

Refrigerator is used for the home purpose to extends the shelf life of perishable foods and cool food and drink that tasted better cold.
It can also be used to keep certain drugs, such as insulin. In a hospital there will be a refrigerator for heat sensitive drugs. 





























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