Performance analysis of a PV/T shading device for enhancing energy saving and human comfort

Blinds have been widely installed in glazed facades to reduce cooling loads and enhance indoor comfort. However, current blinds struggle to efficiently utilize incoming solar energy and cater to the seasonal thermal demands of buildings. To address these challenges, this paper introduces a novel PV/T shading device designed to utilize solar energy on blinds for both electricity generation and heat provision throughout different seasons. To comprehensively assess its performance, an office building was selected as a case study in a region experiencing both heating and cooling demands. The self-fabricated PV/T shading device underwent rigorous testing to validate a developed mathematical model. This model, integrated with TRNSYS software, was used to predict energy performance, while Radiance and Ladybug tools were adopted to assess indoor visual and thermal comfort. After implementing the PV/T shading device with optimized capacity, the NPV of the building over its life cycle was increased by 9709.9 RMB. The time percentage of thermal comfort was improved by 81.7%, and the indoor useful daylight illuminance was increased by 57.2%. Additionally, the glare autonomy was enhanced by 23.3% to 33.6%. Compared to common blinds and PV blinds, the PV/T shading device offered an increase in annual electricity benefits of 131.6 kWh/m2 and 111.6 kWh/m2, respectively, along with an increase of NPV by 1812 RMB/m2 and 1859 RMB/m2. This study demonstrates the excellent performance of the proposed devices and provides a new approach to energy-saving building envelopes.