Highly efficient mechanocaloric cooling using colossal barocaloric plastic crystals
Kun Qian, Shangchao Lin, Zhe Zhang, Bing Li, Yichao Peng, Yijin Li, Changying Zhao
Abstract
Despite the emergence of colossal barocaloric materials with great potential to replace environmentally unfriendly vapor-compression refrigerants, a scalable and cyclic reversible cooling device has not been demonstrated yet. Here, we develop experimental compressive mechanocaloric prototypes using bulk amounts of low-cost plastic crystal neopentylglycol (NPG) with high device-level scalability. Large quasi-adiabatic temperature changes in NPG of 20.8 K for heating and −16.7 K for cooling are achieved during the cyclic pressurization-depressurization processes from ambient pressure to 231 MPa. A maximum temperature drop of 3.8 K and cooling energy of 900 J in water as the heat-exchanging medium are observed in the prototype. Using molecular dynamics simulations, an outstanding coefficient of performance of 14 and cooling energy density of 90 kJ/kg are achieved for the reverse Stirling cooling cycle at a large temperature span of 5 K, while the corresponding values are 7.5 and 30 kJ/kg for the reverse Brayton cooling cycle.