Roadmap for the next-generation of hybrid photovoltaic-thermal solarenergy collectors

Abstract

For hybrid photovoltaic-thermal collectors to become competitive with other types of solar energy converters, they must offer high performance at fluid outlet temperatures above 60°C, as is required for space heating and domestichot waterprovision, whichtogether accountfornearly50%ofheatdemand.Aroadmap ispresentedof the technological advances required to achieve this goal. Strategies for reducing convective, radiative and electrical losses at elevated temperature are discussed, and an experimental characterisation of a novel transparent low-emissivity coating for photovoltaic solar cells is presented. An experimentally-validated simulation formalism is used to project the performance of different combinations of loss-reduction strategies implemented together. Finally, a techno-economic analysis is performed to predict the price points at which the hybrid technologies along the roadmap become competitive with non-hybrid photovoltaic and solar thermal technologies. Themostadvanced hybridtechnology alongthe roadmapemploysanevacuated cavity,a transparent lowemissivity coating, and silicon heterojunction photovoltaic cells.

This work was funded by the Engineering And Physical Science Research Council (EPSRC) grants High Temperature, High Efficiency PV-Thermal Solar System (EP/M025012/1) and Joint UK-India Clean Energy Centre (JUICE) (EP/P003605/1). A. Mellor was supported by the European Commission through Marie Sklodowska Curie International Fellowship, Grant No. DLV-657359.