Ionocaloric refrigeration cycle

Developing high-efficiency cooling with safe, low–global warming potential refrigerants is a grand challenge for tackling climate change. Caloric effect–based cooling technologies, such as magneto- or electrocaloric refrigeration, are promising but often require large applied fields for a relatively low coefficient of performance and adiabatic temperature change. We propose using the ionocaloric effect and the accompanying thermodynamic cycle as a caloric-based, all–condensed-phase cooling technology. Theoretical and experimental results show higher adiabatic temperature change and entropy change per unit mass and volume compared with other caloric effects under low applied field strengths. We demonstrated the viability of a practical system using an ionocaloric Stirling refrigeration cycle. Our experimental results show a coefficient of performance of 30% relative to Carnot and a temperature lift as high as 25°C using a voltage strength of ~0.22 volts. Description Ionic cooling Solid- or liquid-state cooling strategies often rely on caloric effects in which materials are taken through some sort of phase change. Lilley and Prasher found that ions in solution can be used to control the melting and crystallization of a material, creating what the authors refer to as an ionocaloric cycle (see the Perspective by Defay). This cycle could drive refrigeration that is competitive with other caloric cooling strategies. —BG Changing the ionic concentration in a solution drives phase transitions allowing the construction of a refrigeration system.