Performance study of solar photovoltaic-thermal collector for domestic hot water use and thermochemical sorption seasonal storage

Abstract

To maximise the utilisation of solar energy and improve the solar fraction for domestic applications, this paper explored the potential of the hybrid solar Photovoltaic/Thermal (PV/T) collector integrated with a thermochemical sorption thermal storage system. The thermal output was used to provide domestic hot water or stored over seasons in the England city of Newcastle upon Tyne. The performance of the water-cooled PV/T collectors with or without an air insulation layer between the glass cover and the Photovoltaic (PV) cell was compared. The electrical power generation model of the PV cell developed in MATLAB was coupled with a Computational Fluid Dynamics (CFD) model to simulate the simultaneous generation of electrical and thermal energy. The one-diode model was used to simulate the electrical production of the PV cell with the new correlations of the series resistance and the shunt resistance proposed in this work, so that the accuracy of dynamic performance simulation can be improved especially in the cases with relatively higher PV cell temperature. The water outlet temperature was studied at 100 °C to meet the heat supply requirement of the sorption cycle using the working pair strontium chloride-ammonia. It was found that the PV/T collector with air gap could produce 28 L hot water per day per m2 collector (L/(day·m2)) with the electric efficiency of about 10% if the water outlet temperature was required at 100 °C; in contrast, around 133 L/(day·m2) was produced with the electric efficiency of 13% when the water outlet temperature at 40 °C. The PV/T collector without air gap was not competent for the applications studied in this work especially in cold regions. The application case studies suggested that an installation of 26 m2 air-gap PV/T collectors integrated with the strontium chloride-ammonia thermochemical sorption storage system can fully satisfy the annual hot water demand of an ordinary single household in Newcastle upon Tyne with 100% solar sources, and cover at least half of the annual electricity consumption.