Volume 59

Experimental Comparative Analysis of the Photovoltaic Water Flow Window and the Conventional PV Window for Solar Energy Utilization Wenjie Liu, Luyi Sun, Linyu Cheng, Yueqing Gu, Xinru Zhang, Chongchao Pan, Lin Lin

Abstract

Enhancing the performance of transparent building envelopes is a key strategy for improving building energy efficiency. This study presents a photovoltaic liquid flow window (PV-LFW) as an innovative building-integrated photovoltaic/thermal (BIPV/T) solution. Compared to a conventional single-layer cadmium telluride (CdTe) photovoltaic window (SPV), the PV-LFW not only reduces glazing temperatures under intense solar radiation but also enables full-spectrum solar energy utilization, thereby lowering energy consumption for both air conditioning and hot water systems. The research details the conceptual design and working mechanism of the PV-LFW, followed by a comparative experimental evaluation of its thermoelectric performance against the SPV. Results demonstrate that the PV-LFW effectively functions as a solar thermal collector, achieving an approximate 10°C reduction in CdTe solar cell layer temperature and a 14°C reduction in innermost glass temperature at noon. While the PV-LFW offered only marginal improvements in photovoltaic power generation—due to the low temperature sensitivity of CdTe cells—it exhibited high thermal efficiencies (46.1–61.2%), resulting in overall PV/T efficiencies of up to 68.8%. These findings confirm the potential of PV-LFW for integrated solar energy harvesting and its promise for advancing energy-efficient building envelope technologies.

Keywords BIPV/T window, Liquid cooling, CdTe PV window, Solar energy utilization, Building energy saving