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How does a refrigerator work?

Date: 05 Jan 2012   Group: Science and Technology    Category: Science   


Hi
I want to know about the working of a refrigerator(fridge).
I want to know how it cools things.What's the principle behind its cooling ability and what are the materials used in the construction of refrigerators? Does it require any specific materials for cooling?



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Author: Meera Chandrasekharan    06 Jan 2012      Member Level: Gold     Points : 6  (Rs 4)    Voting Score: 0

You guessed right, the working of a refrigerator needs some material. In most of the conventional refrigerators, any volatile liquid is used for cooling. I will explain the process.

A refrigerator (fridge) will comprise of a circular path through which the volatile liquid can move cyclically. A volatile liquid means a liquid that vaporises fastly. The fluid starts its journey from a chamber and it reached near the space where food is kept. It vaporises by absorbing latent heat from the food chamber. Thus the food chamber gets cooled. The vaporised fluid moves in a circular way and reaches a compressor. The compresson converts the vapour back into liquid. The fluid then again circulates. Since all of this takes place fastly, the food chamber will remain cool anytime. The conventional fluid used in refrigerator is freon (I think so, doesn't remember accurately). Some use liquified oxygen as well, I think.

We need electricity in refrigerator because electricity is needed for the functioning of compressor and for circulation of the fluid.

Author: Marut Tiwari    07 Jan 2012      Member Level: Bronze     Points : 6  (Rs 4)    Voting Score: 0

Refrigerator is a general term and it stands for any type of cooling device. Domestic refrigerator (fridge) is one of these types.
A refrigerator consists of a fluid material which vaporizes at relatively low temperature. This fluid is called refrigerant and flows in a cycle during the working of refrigerator. Common refrigerants used in domestic refrigerators are freon, neon and nitrogen. It flows through four components of refrigerator again and again. These four components are cooling chamber, compressor, heat exchanger and expander.
Fluid (in liquid form)goes through the cooling chamber and vaporizes. While it vaporizes, it takes the required latent heat of vaporization from surroundings i.e. cooling chamber. Thus the chamber rejects heat and maintains its temperature lower than ambiance. Further, compressor raises the pressure of refrigerant vapor so that it can flow back through heat exchanger and expander. Electricity is needed to run the compressor. Refrigerant vapor rejects its heat to the ambiance while it flows through heat exchanger and expander. It changes its phase back to liquid in heat exchanger and lowers its pressure in expander. One can see the expander in the form of capillary tube at the rear side of refrigerator.
After it regains its initial properties, it enters the cooling chamber again and the similar processes are followed.




Author: Sai    07 Jan 2012      Member Level: Gold     Points : 5  (Rs 3)    Voting Score: 0

A refrigerator works on the principles of thermodynamics in physics. One of the Laws states that the amount of Heat absorbed from a body is equal to the amount of heat evolved by the body in a different form or the same form. The refrigerator works on this principle converting heat and mechanical energy to heat energy. You must have found the sides of the refrigerator to be hot where as the contents inside it are very cool. The process here is that the refrigerator has a substance called refrigerant which absorbs heat off these contents placed inside it and shifts that heat to the outside without exposing the contents to heat again. Thus it reduces the temperature of these contents and cools them and temperature is maintained at a lower number in it. But at the same time, this absorbed heat has to be given out to satisfy the Law of conservation of energy. Thus the sides of the refrigerator become hot evolving this hear using a pump/heat pump.

This is how a Refrigerator works.

For more information, Please refer to the link below.

Thanks


Reference: http://home.howstuffworks.com/refrigerator2.htm
Author: rakesh yadav    29 Jan 2012      Member Level: Bronze     Points : 6  (Rs 4)    Voting Score: 0

Refrigerator is a device a body can be maintained at a temperature less than outside temperature. It uses a special fluid generally referred as a 'refigerant' . There are wide varities of refrigerants an the market such as R-12,R-22(Freon-22).
R-12(chlorofluorocarbon) is the one which is used in our home fridges. Where as R-22 is used in Air Conditioners used in offices,malls and institutes. where as domestic refrigerators R-12 is used. Butdue to ozone layer depletion problems it has being replaced by R-290, R-134a, R-600.
The working principle of refrigerator is same as that of an air conditioners.These employ a closed cyclic process in which refrigerant is used. The refrigerant has a crucial property of being in vapour state at atmospheric temperature and pressure. Where as it turns into liquid state after compressing in
a compressor. Domestic refrigerators consists of evaporator, compressor, condenser and a expansion device for
refrigerant. Evaporater is the located in freezer, where refrigerant absorbs heat from items kept in refrigerator and
gets evaporated. Then, after turning into vapour it is compressed by compressor where it turns into liquid form.
While the liquid refrigerant is passed through condenser(the coils which are at the back side of the refrigerator) it gets cooled. After that it is sent to expansion device(capillary tube) where its pressure is decreased.In general freezer is the coldest portion of the cabinet. Then followed by chiller tray. While coming down, there are compartments with progressive higher temperatures. The bottom most portion compartment in the least cold one made for vegetables.


Applications:- They are widely used for

1). Domestic purpose
2). Fish storage
3). Cold storage
4). Diary industries
5). Medicines
6). A/C busses, trains, cars, and airoplanes.
7). Telecom industry
8). Mostly in offices for better functioning of the computers

Author: Ashadul Halder    26 Jul 2012      Member Level: Bronze     Points : 2  (Rs 2)    Voting Score: 0

Refrigerator works in Joule-Tharmal process. At first gas is compressed with very high pressure. Then that gas is allowed to pass through a low pressure or normal Pressure zone, Which surrounded by Water which has very high sp. heat. Now according to theory of thermo-dynamical theory, the heat energy converted to kinetic energy at the releases of gas in that low pressure zone. And Freon and other gasses are used to keep up the coolness.
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