Refrigeration

Heat and cold are two different entities associated with temperature. Body temperature is measured by a thermometer. We prefer to wear light coloured cotton clothes when it is hot. We prefer to wear light coloured cotton clothes when it is hot. We prefer to wear dark coloured polyester clothes when it is cold as per the weather. Heating is the process of upkeeping the heat in the body. Refrigeration is the process of cooling space.

Refrigeration involves the process of removing heat from a body and cooling it to a lower temperature than the actual. Refrigerators are used for the refrigeration process.

History of Refrigeration

This process was witnessed, in the Greeks and Romans period to cool their food with ice transported from the mountains. Preservation of the food is the main idea which leads to the development of the refrigeration process. Refrigeration inhibits the growth of microorganisms like bacteria, yeast and mold thus helping in the destroying of food items. It is mainly used to store foodstuff at low temperatures for a longer period of time. Some products can be stored for months and even for many years. Water when freezed becomes ice which is the key ingredient of many processes. Packed snow and ice could be preserved for months.

Working Principle of Refrigerator

Refrigerators work on the second law of thermodynamics. In the process of refrigeration, unwanted heat is taken from one place and discharged into another. The common refrigerator which we have in our homes, works on the principle of evaporation. A refrigerant is a substance used in a heat cycle to transfer heat from one area, and remove it to another. A refrigerant when passed through the food kept in the refrigerator, it absorbs heat from these items and transfers the absorbed heat to the surrounding with less temperature.

The Components of Refrigerator

There are four components in the refrigerator system. They are:

• Evaporator
• Compressor
• Condenser
• Expansion valve

Evaporator: It is the main part of the refrigerator that helps to keep the device and things cool always. It features the tubes with high thermal conductivity that helps in absorbing the heat rejected by the fan or coil in the system.

Compressor: It compresses the low-pressure, low-temperature vapor into a high-temperature, high-pressure vapor. The refrigerant is passed from the evaporator and is compressed in a cylinder to generate a high-temperature, high-pressure gas.

Expansion valve helps to control the flow of refrigerant into the evaporator, or cooling coil. Expansion valve is also known as flow control valves. It is a sensitive small device that aids to sense the temperature change of the refrigerant.

Condenser: It comprises a set of tubes with external fins placed back of the refrigerator. This component helps to convert the gaseous refrigerant into liquid form.

Working Of The Refrigerator

Vapour compression refrigeration cycle is followed for the refrigeration process. In this process, the Evaporator, Compressor, Condenser and expansion valves are connected to tubes made of copper or steel.

Evaporator tube is placed throughout the refrigerator, when heat is absorbed the liquid refrigerant absorbs the heat and then converts into vapour. The heat absorbed is passed to the external environment through the compressor from vapour state to liquid state. This process repeats when the heat is absorbed and passed through the expansion valve to the evaporator. This process helps to keep the refrigerator cool always.

Read more about Murphy’s law.

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