Analysis of factors affecting the electrothermal performance of STPV liquid-flow windows at various flow rates

¹ School of Architecture, Tianjin University, Tianjin, 300072, China
² APEC Sustainable Energy Center, Asia-Pacific Economic Cooperaion (APEC)/National Energy Administraion (NEA)of China, Tianjin 300072, China

^* Corresponding author: yujiaohuo@163.com

Abstract

The structural design of photovoltaic windows is fundamental to their thermal and electrical performance. Photovoltaic windows with closed or ventilated air layers, as commonly addressed in existing studies, fail to efficiently collect and transfer heat within the window system. This paper presents a model of an STPV liquid-flow window, which incorporates a liquid flow cavity between the STPV module and conventional glass. The experiment was conducted over four sunny days, and the liquid flow rates into the STPV window were set at 0.2 L/min, 0.4 L/min, 0.6 L/min, and 0.8 L/min, respectively. The experimental results and analyses show that, an inlet flow rate of at least 0.4 L/min effectively eliminates significant temperature gradients on the indoor surface for the model presented. Global solar irradiation exerts the greatest influence on both thermal insulation performance and PV operating temperature, while liquid flow rate plays a critical role in reducing indoor direct heat gain. The operating temperature of the PV system ranges from 22.5 °C to 29 °C. Because the inlet design temperature closely approximates the PV operating temperature, thereby limiting the liquid flow system’s potential to enhance cooling as the flow rate increases.