Solar collectors and photovoltaics as combined heat and power systems: A critical review

A main method to increase the solar energy utilization efficiency is to combine heat and power generation together. In this paper, a critical review of the literature on solar combined heat and power systems (CHP) is conducted, which includes solar photovoltaic/thermal systems, concentrated photovoltaic/thermal systems, and various combination with different solar collectors and applications. It shows that there are serious gaps in this field, which calls for more research. The modeling and analysis of the electrical parts of the CHP systems are not adequate, and there are limited studies on the economic and exergy assessments of the solar concentrating CHP systems. The solar collectors for combined CHP were focused on optimizing the performance of the maximum average useful power generation and minimum total heat transfer area, little environment impact analysis was conducted. Careful exergy, economic and environmental analysis on both electronic and thermal performance is suggested, especially for large CHP system. Also, further studies are recommend for investigating the hybrids of concentrating collectors with CHP, with considering the economic issues.