Ans.

Refrigeration plays an important role in a wide range of human activity and keeping people and things cool consumes huge amounts of energy. They use fluids such as hydrofluorocarbons which are susceptible to leakages, and can contribute to global warming.

An alternative approach involves using “caloric” materials, which release heat when subjected to an external stimulus such as an applied magnetic or electric field or a compressive force. When the stimulus is removed, the material will absorb heat, thus cooling its surroundings.

Recently, owing to the strong demand for efficient and environmentally friendly refrigeration technologies, materials with giant caloric effects, including elastocaloric, have been widely investigated.

Elastocaloric Effect:

When rubber bands are twisted and untwisted, it produces a cooling effect. This is called the “elastocaloric” effect.

The elastocaloric effect can be regarded as the entropy change under isothermal condition or temperature change under adiabatic condition when a mechanical stress is used or released in a given material.

Energy is the ability to do work. Although all forms of energy are interconvertible, and all can be used to do work, it is not always possible, even in principle, to convert the entire available energy into work. Entropy is a measure of how much energy is not available to do work.