Updated: Apr 18, 2019 18:52 IST
<! – 8 min ago
Washington D.C. [USA]Apr 18 (ANI): In a recent study, researchers have found an eco-friendly material that could replace the traditional coolants used in most refrigerators and air conditioners.
The research was published in the journal Nature Communications.
When put under pressure, plastic crystals of "neopentylglycol" yield huge cooling effects ̵
The gases currently used in the fixed majority of refrigerators and air conditioners hydrofluorocarbons and hydrocarbons (HFCs and HCs) – are toxic and flammable. When they leak into the air, they also contribute to global warming.
"Refrigerators and air conditioners based on HFCs and HCs are also relatively inefficient. That's 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.
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
Conventional cooling technologies rely on the thermal changes that occur when compressed fluid expands. Most cooling devices work by compressing and expanding fluids such as HFCs and HCs. As the fluid expands, it decreases in temperature, cooling its surroundings
With solids, cooling is achieved by changing the material's microscopic structure. This change can be achieved by applying a magnetic field, an electric field or through mechanical force.
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 or neopentyl glycol (NPG) and other related organic compounds have produced the playfield.
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. It is not only widely available but also is inexpensive.
NPGs, molecules of carbon, hydrogen and oxygen, are nearly spherical and interact with each other only weakly. These loose bonds in their microscopic structure permit the molecules to rotate relatively freely.
The word "plastic" in "plastic crystals" refers to not to its chemical composition but rather to its malleability. Plastic crystals lie at the boundary between solids and liquids.
The temperature change achieved is comparable with that exploited commercially in HFCs and HCs.
The discovery of colossal barocaloric effects in a plastic crystal should bring barocaloric materials to the forefront of research and development to achieve safe environmentally friendly cooling without compromising performance. (ANI)