This change can be achieved by applying a magnetic field, an electric field or through mechanic force.In a recent study, researchers have found an eco-friendly material that could replace the traditional coolants used in most refrigerators and air conditioners. As the fluid expands, it decreases in temperature, cooling its surroundings. The temperature change achieved is comparable with those exploited commercially in HFCs and HCs.The research was published in the journal Nature Communications.The word ‘plastic’ in ‘plastic crystals’ refers not to its chemical composition but rather to its malleability. Most cooling devices work by compressing and expanding fluids such as HFCs and HCs. Plastic crystals lie at the boundary between solids and liquids.Conventional cooling technologies rely on the thermal changes that occur when a compressed fluid expands. In addition, the material is inexpensive, widely available and functions at close to room temperature. Thats important because refrigeration and air conditioning currently devour a fifth of the energy produced worldwide, and demand for cooling is only going up,” said Dr Xavier Moya, a researcher.When put under pressure, plastic crystals of neopentylglycol yield huge cooling effects- enough that they are competitive with conventional coolants.Due to the nature of their chemical bonds, organic materials are easier to compress, and NPG is widely used in the synthesis of paints, polyesters, plasticisers and lubricants.The gases currently used in the vast majority of refrigerators and air conditioners- hydrofluorocarbons plastic airless bottle and hydrocarbons (HFCs and HCs) – are toxic and flammable. Its not only widely available but also is inexpensive.With solids, cooling is achieved by changing the materials microscopic structure.”Refrigerators and air conditioners based on HFCs and HCs are also relatively inefficient.To solve these problems, materials scientists around the world have sought alternative solid refrigerants..In the study, researchers described the enormous thermal changes under pressure achieved with plastic crystals.NPGs molecules, composed of carbon, hydrogen and oxygen, are nearly spherical and interact with each other only weakly.Compressing NPG yields unprecedentedly large thermal changes due to molecular reconfiguration.For decades, these caloric effects have fallen behind the thermal changes available in fluids, but the discovery of colossal barocaloric effects in a plastic crystal of neopentylglycol (NPG) and other related organic compounds has levelled the playfield. These loose bonds in its microscopic structure permit the molecules to rotate relatively freely. When they leak into the air, they also contribute to global warming
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