Optical design and validation of a solar concentrating photovoltaic-thermal (CPV-T) module for building louvers

This paper presents a solar concentrating photovoltaic-thermal (CPV-T) module for building louver which is designed to provide electricity and heat for buildings by capturing solar radiation in building vertical space. A specially designed concentrating blade used for louver is combined with a PV-T module. The concentrating blade enables incident sunlight converge to a solar cell, thus obtaining electricity. The heat generated in the solar cell is taken away and collected by thermal fluid, by which the deficiency of increasing extra cooling demand in summer existing in traditional building integrated photovoltaic is overcome. The concentrating blade is designed to work under the solar incident angle of 0–90°, and its high-efficiency photovoltaic-thermal working range is 20–70°. Optical simulations are conducted to illustrate the characteristics of the concentrating blade. Remarkably, the maximum geometrical concentration ratio is 2.96 at the incident angle of 20°. Over a wide range of incident angles between 12.5° and 52.5°, the geometrical concentration ratio maintains above 2. Finally, experiments are carried out to test the electrical and thermal performance of the CPV-T module. The results illustrate that its overall efficiency can reach above 55 % for nearly 5 h without tracking during the all-day experiment.