Novel solar-powered photovoltaic/thermoelectric hybrid power source

Abstract

A photovoltaic (PV) module converts solar radiation into electric power. Solar collectors convert directly solar heat into hot water (not electric power). A thermoelectric generator (TEG) directly converts solar heat into electric power. Thus, this study combines a PV module with some TEGs to directly convert both solar radiation and solar heat into electric power. The result is a novel solar-powered PV/thermoelectric hybrid power source. The output power of a TEG module is very small when temperature difference between its two surfaces (hot and cold) ranges below about 50C∘. As a result, TEGs cannot be used in low-grade heat harvesting applications such as solar heat harvesting. This study also solves this defect, so that, the mentioned temperature difference is raised by utilizing a two-phase closed thermosiphon (TPCT) heat pipe, a concentrator and a radiator. A prototype of the proposed PV/thermoelectric hybrid power source has been constructed, and experimental results obtained from its operation under realistic conditions are given. The novelties and contributions of this research work can be outlined as below:The PV/thermoelectric hybrid power source directly converts both solar radiation and solar heat into electric power.The technique used to design and construct the PV/thermoelectric hybrid power source enables utilizing TEGs in low-grade heat harvesting, in particular, solar heat harvesting.The technique provides a dc bus with constant voltage, so other power generation devices such as fuel cell and wind power generation system can be easily added to the system by connecting them to the dc bus through a converter.The technique uses a high-efficient maximum power point tracking (MPPT) method which is a modified and high-efficient version of perturb and observe (P&O) method with adaptive and variable step size.