Technology

Understanding Refrigeration

Air conditioning is the process of treating the air to control its temperature, moisture content, cleanliness, odor, and circulation as needed by the occupants of a place, a process, or products all at the same time.

Refrigeration and air conditioning system have a long history that dates back to the human need for sustenance and comfort. The history of refrigeration is fascinating since it includes issues such as refrigeration availability, advances in prime movers and compressors, and refrigeration methods.

refrigeration system

In this article, you’ll learn the definition, applications, diagram, method, types, working, advantages, and disadvantages of refrigeration.

 

Read more: Understanding an Air Conditioning System

 

What is refrigeration?

A refrigeration system, in general, is the process of cooling, and it entails removing heat and disposing of it at a higher temperature. As a result, refrigeration is a technology that moves heat from a lower to a higher temperature.

Refrigeration is used in air conditioning and heat pumps, in addition to cooling applications. Physics and thermodynamics are the fundamental principles, and they apply to all applications.

The preservation of perishable food goods by storing them at low temperatures is one of the most well-known applications of refrigeration. Refrigeration systems are also commonly employed to provide humans with thermal comfort via air conditioning.

Applications of Refrigeration

The followings are the applications of refrigeration system

  • In the chemical industry, cooling systems are often used to separate and liquefy gases and vapors.
  • These are ideal for the production of ice.
  • Refrigeration is most commonly used to keep perishable items fresh in cold storage.
  • A refrigeration system is utilized to cool the water if it is necessary.
  • In the manufacture and heat treatment of steel, it is used to manage the humidity of the air.
  • In oil refineries, for cooling the oil to remove wax.
  • In the pharmaceutical industry, for the preservation of tablets and medicines.
  • They’re also employed in medical areas to preserve blood, medicinal fields, tissues, and other things.
  • In hospitals, theaters, and other public places, air conditioning is used for comfort.

Diagram:

refrigeration-cycle-complete

Methods of refrigeration

The following are the common methods of refrigeration

  • Ice refrigeration
  • Dry ice refrigeration
  • Steam jet refrigeration
  • Throttling refrigeration
  • Liquid refrigeration
  • Air refrigeration

 

Read more: Understanding automobile air conditioning system

Ice refrigeration

The ice is retained in the refrigerator’s cabinet and serves as a cooling system. Food was refrigerated and preserved using ice. Most ancient cultures, including the Chinese, Greeks, Romans, and Persians, collected snow and ice on a seasonal basis for ages.

Snow and ice were stuffed into tunnels with straw or other insulation, and the Persians kept the ice in a pit. Ice rationing allowed foods to be preserved during hotter temperatures.

Ice has its own cooling properties, with a melting point of 0 °C (32 °F) at sea level. Ice must absorb 333.55 KJ/kg of heat to melt. Foods stored at or around this temperature have a longer shelf life.

Dry ice refrigeration

Dry ice (frozen carbon dioxide) is cooled by melting upwards in the non-cyclic refrigeration method. Dry ice refrigeration systems are utilized in laboratories, workshops, and portable coolers for small-scale applications.

At normal atmospheric pressure, solid carbon dioxide has no liquid state and transitions from solid to vapor at temperatures of -78.5 °C (-109.3 °F). It works well for keeping items at low temperatures during the sublimation process. Total loss refrigeration refers to systems in which the refrigerant evaporates and escapes into the atmosphere.

Steam jet refrigeration

Steam is fed through a high-efficiency vacuum ejector in this method of refrigeration, and it is ejected into a separate, closed vessel that is part of a cooling water circuit. The water evaporates in the closed vessel due to the partial vacuum, releasing heat through evaporative cooling.

The cooled water is now fed to the air cooler through the cooling circuit, while the evaporated water from the ejector is collected in a separate condenser before being returned to the cooling circuit.

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Throttling refrigeration

The refrigeration method is linked to the throttling effect. It’s just the process of lowering the liquid refrigerant’s pressure as it goes through the expansion device. By lowering the pressure, the liquid refrigerant flashes into a vapor, which cools the system.

Liquid refrigeration

Liquid nitrogen is useful as an extreme coolant for short overclocking sessions because it boils at -196 °C, much below the freezing point of water. To trap nitrogen and prevent excessive temperature swings, evaporation designs ranging from cut-out heat sinks with pipes linked to copper containers are used.

After the nitrogen has evaporated, however, it must be supplied. In a typical liquid nitrogen cooling installation. On top of the processor or graphics card, copper or aluminum pipes are mounted. Liquid nitrogen is discharged into the pipe after it has been substantially insulated against condensation, resulting in a temperature reduction of 100 degrees Celsius.

Air refrigeration

The refrigerant in air refrigeration systems is air, which compresses and expands to provide heating and cooling capability.

One of these is air cycle refrigeration, which offers a good alternative to CFC refrigerants as well as low energy usage and capital costs in certain applications. Refrigeration systems of this type are extensively employed in scientific, industrial, and commercial applications.

Types of refrigeration

The followings are the common types of refrigeration:

  • Mechanical compression refrigeration
  • Evaporative cooling
  • Absorption refrigeration
  • Thermoelectric refrigeration
  • Vapor compression refrigeration
  • Vapor absorption refrigeration

 

Read more: Different types of refrigeration systems

Working principle

 

The working principle of refrigeration is less complex and can be easily understood. A refrigerator is a machine that extracts heat from a body that is at a low temperature and then rejects it to a body that is at a high temperature. A refrigerator is a machine whose primary function is to cool a particular thing.

Heat does not transfer from a low-temperature body to a high-temperature body without the assistance of external labor, according to the second rule of thermodynamics (Clausius statement). As a result, external labor is required to operate a refrigerator.

With the help of an external source, a heat engine can run in a reversible cycle. Heat is absorbed from a cold body and rejected by a hot body in this cycle. As a result, the engine is known as a heat pump. Heat is extracted from the cold body and refused to the hot body in the refrigerator as well. As a result, the refrigerator uses a reversed heat engine cycle.

Watch the video below to learn how refrigeration works:

Advantages and disadvantages of Refrigeration

Advantages:

The followings are the benefits of refrigeration in their various applications:

  • Most of the time, the air is utilized as a refrigerant since it is widely available and cheap.
  • Refrigeration systems are simple to design and produce, with few complicated parts and low maintenance costs.
  • Non-toxic, non-flammable, and non-corrosive refrigerant is used.
  • If the refrigeration system is run much beyond its design parameters, there will be no substantial change in its performance. They might result in a significant temperature difference between hot and cool areas. As a result, the cooling and heating effects are achieved using the same system.

Disadvantages:

Despite the good advantages of refrigeration, some limitations still occur. Below are the disadvantages of refrigeration in its various applications:

  • In comparison to other refrigeration cycles, the refrigeration system has a lower coefficient of performance.
  • The refrigeration system’s operating costs are rather expensive.
  • This system’s components are bulky and take up a lot of room.
  • Because the air carries impurities, open systems should clean their air filters on a regular basis.

 

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Conclusion

There are two types of refrigeration systems: one for frozen things and another for items that need to be refrigerated but aren’t frozen. It can remove all of the heat generated by the load inside the containers, making them cooler and extending their life. However, the process of obtaining and maintaining a temperature below ambient with the goal of cooling a product or area to the required temperature is referred to as refrigeration.

That is all for this article, where the definition, applications, diagram, method, types, working, advantages, and disadvantages of refrigeration system are being discussed. I hope you learned a lot from the reading, if so, kindly share with other students. Thanks for reading, see you around!