REFRIGERATION
How do we define a refrigeration?
Refrigerators operate under the second law of thermodynamics. Unwanted heat is removed from one location and discharged into another during the refrigeration process.
A refrigerant is a substance that is used in a heat cycle to transfer heat from one location to another.
There are four components in the refrigerator system. They are:
- Evaporator
- Compressor
- Condenser
- Expansion valve
The requirement for and comfort of humans now include refrigeration. The most often used form of refrigeration is vapor compression. Regrettably, the refrigerants employed in vapor compression systems contribute significantly to concerns with global warming and ozone layer depletion. As a result, new refrigerants and refrigeration technologies are being eagerly anticipated by the refrigeration sector. There are numerous more techniques to produce refrigeration in addition to the well-known vapor compression method like magnetic refrigeration, steam jet refrigeration, thermoacoustic refrigeration the details of which are discussed below.
MAGNETIC REFRIGERATION
Warburg made the initial discovery of the Magneto Caloric Effect in 1881. The magneto caloric effect was explained by Weiss and Piccard in 1918. In low-temperature physics, magnetic refrigeration has been a standard method since the 1930s. Brown created the first magnetic refrigerator that operated at ambient temperature in 1976. The key benefits of the magneto caloric effect (MCE) principle over traditional VCRS are that it doesn't create any chemicals that harm the ozone layer or contribute to global warming, and it has excellent energy efficiency.
To create magnetic freezers with a strong magnetic field, superconducting magnets can be employed. Superconducting magnets can be used in industrial applications such building climate control, supermarket chillers, and refrigeration facilities. However, as superconducting magnets require liquid helium or a cryocooler to keep the superconducting coil efficient, the use of these magnetic sources in home refrigerators is ruled out.
- Heating the material
- Expelling the heat
- Cooling the material
- Absorbing the heat
magnetic refrigeration requires the combination of a relatively strong magnetic field and a material with a large magneto caloric effect, magnetocaloric materials include pure elements such as Gadolinium or alloys such as Lanthanum-iron-silicon (LaFeSi) or Iron-phosphorus (Fe2P).
STEAM JET REFRIGERATION
The refrigeration cycle used by the steam jet system is powered by heat. Le Blanc and Parson invented the steam jet refrigerator in the year 1900. The benefit of jet refrigeration is that, in comparison to other kinds of refrigeration systems, it is very easy to design, build, and run. Water, the most environmentally benign refrigerant, can be used with it. Solar thermal energy is the main type of energy used. It uses the basic principle of boiling of liquid at lower temperature by reducing pressure on its surface
Steam jet refrigeration system is widely used in paper mills, breweries, food processing plants, gas plants etc.
THERMOACOUSTIC REFRIGERATION
The science of thermoacoustic examines both sound and thermal energy. Thermoacoustic phenomena were seen by Byron Higgins. At the Los Alamos National Laboratory, Hofler constructed the first thermoacoustic cooler. Sound waves are used by thermoacoustic refrigeration systems to create a cooling effect. By compressing and expanding an inert gas, such as helium, argon, air, or a mixture of gases in a resonator, the cooling effect is produced.
The thermo acoustic devices are mainly divided into standing wave systems and traveling wave systems and are shown in figures
STANDING WAVE SYSTEM TRAVELING WAVE SYSTEM
The technology's primary advantage is the use of inert gases that are harmless for the environment, like helium, argon, and air.
The high expense and complexity were also shown to be due to the heat exchangers.
Authors:-
1. Asem Mohammed
2. Mitali Barahate
3. Minal Chaudhari
