Research progress on utilization of phase change materials in photovoltaic/thermal systems: A critical review

A photovoltaic/thermal (PV/T) technology, producing electricity and heat simultaneously, has attracted extensive attention. Integration of phase change materials (PCMs) into PV/T systems as auxiliary cooling media or/and heat storage media to improve the system performances has been prevalent in recent years. This paper aims to critically and comprehensively review the research progress concerning utilization of PCMs in PV/T systems. The adopted performance evaluation indexes and applied PCMs in various PV/T systems are gathered and analysed. The configurations and effects of bulk PCMs in standalone PV/T modules, building-integrated PV/T systems and PV/T systems integrated with other energy conversion technologies are elaborated with special attention paid to the microencapsulated PCM (MPCM) slurry applied in PV/T modules. The effects of thermophysical properties and mass of PCM/MPCM, operation parameters of working fluids, and environmental conditions are also discussed, whilst heat transfer enhancement approaches for PV/T-PCM modules are explored. It has been identified that the integration of PCMs can effectively elevate the system performances when the phase change temperature and operation parameters are carefully tailored according to environmental conditions. Finally, research prospects and opportunities are proposed in terms of material fabrication and modification, system integration, model development as well as performance analysis. The review can provide crucial references for high-efficiency PV/T-PCM system design and further development of relevant technologies.