Performance evaluations and applications of photovoltaic-thermal collectors and systems

As a kind of renewable energy, solar energy is paid more and more attention all over the world. Solar energy utilization system can be classified into two categories: thermal systems which convert solar energy to thermal energy, and photovoltaic systems which convert solar energy to electrical energy. Normally, both types of the collectors are used separately. In solar thermal system, the solar thermal energy can be used for heating working fluid via a heat collector. The conventional electrical energy is used to circulate working liquid through the collector. The use of conventional electrical energy can be avoided if combination of both types of thermal collector and photovoltaic collector is hybrid in one unit named photovoltaic-thermal collector (PV/T). In order to fully develop the applications of the photovoltaic-thermal collectors and systems, more researches on performances and characteristics of the photovoltaic-thermal collectors and systems have been carried out. This paper presents the performance evaluations and applications of the photovoltaic-thermal collectors and systems. The performances of the photovoltaic-thermal air collectors and photovoltaic-thermal water collectors are analyzed and discussed. The applications of the photovoltaic-thermal systems, such as building integrated photovoltaic-thermal systems, concentrating photovoltaic-thermal systems and photovoltaic-thermal heat pump systems are presented. Several factors affecting the performances and characteristics of the photovoltaic-thermal systems are also summarized. (C) 2014 Elsevier Ltd. All rights reserved.