All hybrid photovoltaic-thermal (PV-T) system designs and applications developed to date at both the research and industry level have been reviewed by an international research team.

The assessment published in Progress in Energy and Combustion Science considers conventional PV-T collectors, air-based systems, liquid-based installations, water-based collectors, refrigerant-based systems, heat-pipe-based technologies, dual air-water systems, building-integrated PVT arrays and concentrated PVT collectors. The analysis also addresses possible collector modification designs, PVT configurations for glazing, novel thermal absorber technologies, and the use of phase-change materials (PCMs) and aerogels. Prospects for integrating new technologies such as tandem solar cells, selective coatings, spectral splitting, dichroic mirrors/filters, holographics, luminescent splitters/concentrators, nanofluids or heat transfer and optical absorption techs into PVT systems are discussed.

All of the PV-T collectors examined can be integrated with solar heating and cooling (SHC) technologies to generate electricity, heating or cooling. The most suitable PV-T collector and SHC technology depend on the specific location (solar irradiance, ambient temperatures) and specific application, among others. Additional research on the long-term operation of PV-T systems to assess the long-term reliability of collectors is warranted.

Air-based PV-T collectors can be a cost-effective technology for sites with low irradiance levels and low ambient temperatures where significant space heating is required almost all year long. In areas with high solar irradiance and ambient temperatures, water-based PV-T collectors are suitable for preheating water for domestic hot water and space heating.

Researchers from University of Zaragoza (Spain), Imperial College London (U.K.), Zhejiang University (China), Karlsruhe Institute of Technology (Germany), Boise State University, University of New South Wales (Australia), Cyprus University of Technology (Cyprus) and University of Birmingham (U.K.) contributed to this technology review.