Performance Evaluation and Optimization of a Building-Integrated Photovoltaic/Thermal Solar Water Heating System for Exterior Shading: A Case Study in South China

Building-integrated photovoltaic/thermal (BIPV/T) systems can produce both electrical and thermal energy through the use of photovoltaic/thermal modules integrated with building envelope. Exterior shading is a common way to improve summer indoor thermal environment of the buildings in low latitudes. This study presents a BIPV/T solar water heating system for exterior shading of residences. In order to evaluate and optimize the system performances, a model was developed to simulate the thermal and electrical production of such system. The simulations for an example system in Guangzhou, a city in South China, were performed to investigate the influences of tank installation height and panel tilt angle on system performances. According to simulation results, the suggested tank installation height is 0.6~0.8 m. The shading coefficient ranges from 0.797 to 0.828 when the tilt angle varies from 14° to 38°. The reduction of panel tilt angle causes a certain improvement of shading performance. The annual auxiliary heat reaches the minimum when the panel tilt angle equals 28°, and the annual electric energy output changes little when the panel tilt angle ranges from 20° to 28°. Comprehensively considering thermal, electrical, and shading performances, the suggested panel tilt angle is 20°~28°. The average thermal and electrical efficiencies are respectively 38.25% and 11.95% when the panel tilt angle ranges from 20° to 28°. The presented system is a promising way to provide hot water, electricity, and exterior shading for residences.