Phase Change Materials

Abstract Phase change materials (PCMs) store thermal energy via the latent heat of phase transitions. PCMs can be used to provide district cooling (subambient transition temperatures), to buffer thermal swings in buildings (near ambient transition temperatures), and to store solar thermal energy for short-term or seasonal applications (higher transition temperatures). When thermal energy is from an intermittent source, such as solar radiation or waste heat, the ability to store energy in a compact form can provide a readily accessible source of heat. Issues concerning the thermal conductivity, stability, cyclability, phase segregation, supercooling, containment, cost, safety, and sustainability of PCMs are addressed, and research challenges that, when solved, would allow widespread use of PCMs are presented.