Refrigeration means production of cold, i.e., to bring and maintain the temperature of an enclosed space below that of its surroundings. This enclosed space can be a refrigerator cabin or deep freeze cabin or cold storage, etc. that is being used to store food/ dairy products at low temperature. It can also be an air-conditioned room or building where low temperature of air is required for human comfort. In this way, refrigeration has very wide applications such as food preservation in domestic as well as in food/dairy industries, ice-manufacturing, ice cream manufacturing, textile industries, air conditioning of buildings, transport air conditioning,liquidification of gases, research and medical applications, etc. We are familiar to these different uses of refrigeration. But we don’t know about how the refrigeration/cold is produced, how a refrigeration system works, what are the various components of refrigeration etc. We will learn about how and why of refrigeration in this unit.
The temperature of an enclosed space can be lowered down and maintained if we are able to extract heat energy by some means from the space. On extraction of heat energy, the temperature of the space lowers downs. Due to the temperature difference, heat will again flow itself from high temperature surrounding to low temperature space and tend to increase its temperature. To maintain the space cold,this heat inflow is also continuously required to be extracted by the refrigerating machine. However, providing insulation around the space can reduce this heat inflow. Thus the refrigeration load reduces by insulation.
In this way refrigeration means producing and maintaining cold in an enclosed space by extraction of heat energy and retarding the natural flow of heat from surroundings to the space by insulating it. Now the question is that how this heat energy can be extracted or what are the possible methods of production of refrigeration?
There are many methods as ice-refrigeration, air refrigeration, steam-jet refrigeration,vapour compression refrigeration, vapour absorption refrigeration, by using liquid gases, thermo-electric cooling, adiabatic demagnetization, etc. The most common and widely used method of refrigeration is Vapour-Compression Refrigeration System. In most of the dairy and food industries, this system is used. Here we will discuss it in detail.
The temperature of an enclosed space can be lowered down and maintained if we are able to extract heat energy by some means from the space. On extraction of heat energy, the temperature of the space lowers downs. Due to the temperature difference, heat will again flow itself from high temperature surrounding to low temperature space and tend to increase its temperature. To maintain the space cold,this heat inflow is also continuously required to be extracted by the refrigerating machine. However, providing insulation around the space can reduce this heat inflow. Thus the refrigeration load reduces by insulation.
In this way refrigeration means producing and maintaining cold in an enclosed space by extraction of heat energy and retarding the natural flow of heat from surroundings to the space by insulating it. Now the question is that how this heat energy can be extracted or what are the possible methods of production of refrigeration?
There are many methods as ice-refrigeration, air refrigeration, steam-jet refrigeration,vapour compression refrigeration, vapour absorption refrigeration, by using liquid gases, thermo-electric cooling, adiabatic demagnetization, etc. The most common and widely used method of refrigeration is Vapour-Compression Refrigeration System. In most of the dairy and food industries, this system is used. Here we will discuss it in detail.
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