Researchers at the University of Cambridge’s Department of Materials Science and Metallurgy in the UK are developing a solid-state cooling technology to solve the cooling challenge.
This non-vapor compression technology, known as barocaloric cooling technology, could potentially transform existing air conditioning technology and make it more climate-friendly. Instead of using refrigerant gases with high global warming potential (GWP) such as the HFCs or HCFCs common to vapor compression technology, this solid-state barocaloric cooling technology takes advantage of the properties of solid organic “plastic crystal” materials to provide cooling.
By applying pressure to these organic solid crystals, it is possible to change their molecular orientation, which results in a solid-state phase transition, thus causing a change in their entropy (degree of disorder) that leads to a temperature change of the system. The process of continuously applying and releasing pressure on the barocaloric material results in solid-to-solid phase changes in the crystals, which generates large thermal changes due to molecular reconfiguration. This produces a cooling effect that can be delivered either to the room air or to produce chilled water for cooling. These plastic crystals are flexible materials that are widely available, low in cost, and nontoxic. Research shows that the thermodynamic behavior of these plastic crystal materials is very similar to commonly used refrigerants, which offers the potential to create a viable alternative cooling approach to the century-old vapor compression technology.