Note4Students

From UPSC perspective, the following things are important :

Prelims level : Elastocaloric effect

Mains level : Elastocaloric effect and its applications

Elastocaloric effect

• When rubbers bands are twisted and untwisted, it produces a cooling effect.
• This is called the “elastocaloric” effect, and researchers have suggested that it can be used in a very relevant context today.
• Researchers have found that the elastocaloric effect, if harnessed, may be able to do away with the need of fluid refrigerants used in fridges and air-conditioners.
• These fluids are susceptible to leakages, and can contribute to global warming.

How it works?

• In the elastocaloric effect, the transfer of heat works much the same way as when fluid refrigerants are compressed and expanded.
• When a rubber band is stretched, it absorbs heat from its environment, and when it is released, it gradually cools down.
• In order to figure out how the twisting mechanism might be able to enable a fridge, the researchers compared the cooling power of rubber fibres, nylon and polyethylene fishing lines and nickel-titanium wires.
• They observed high cooling from twist changes in twisted, coiled and supercoiled fibres.

Efficiency

• The level of efficiency of the heat exchange in rubber bands “is comparable to that of standard refrigerants and twice as high as stretching the same materials without twisting”.
• To demonstrate this setup, the researchers developed a fridge the size of a ballpoint pen cartridge that was able to bring down the temperature of a small volume of water by 8°C in a few seconds.
• They suggested that their findings may lead to the development of greener, higher-efficiency and low-cost cooling technology.