Photovoltaic/thermal systems based on concentrating and non-concentrating technologies: Working fluids at low, medium and high temperatures

Abstract The present article provides an overview about photovoltaic/thermal systems categorised by the temperature of working fluid: Low-temperature (lower than 60 °C), medium-temperature (between 60 and 90 °C) high-temperature (higher 90 °C). Concerning photovoltaic/thermal-air for low-temperature use, majority studies involve building-integrated non-concentrating with phase change materials working-fluid temperatures at around 30–55 °C. photovoltaic/thermal-water systems, a large number are configurations appropriate and, in general, domestic applications fluids approximately 50–60 °C. Regarding references industrial (working fluids: air; water) 60–70 °C temperatures. literature review concentrating shows that investigations concern concentration ratios up to 190X 62–90 °C, water-desalination applications. As most them have 1000X, parabolic concentrators use water (as fluid) 100–250 °C. Moreover, field building applications, consist triple-junction or silicon-based cells. In light issues mentioned above, critical discussion key challenges (in terms materials, efficiencies, technologies, etc.) presented.