Experimental study on thermal, electrical and energy performance of solar PV vacuum glazing (SVG) insulated walls in hot climates

Abstract

Buildings are significant energy consumers, making energy-efficient envelopes essential for reducing carbon emissions. Solar PV vacuum glazing (SVG)-insulated walls offer a dual-function solution by enhancing thermal insulation and generating clean electricity. However, limited experimental research has constrained understanding of their thermal behaviour and energy-saving potential in real building applications. This study adopts a two-phase experimental approach. First, indoor tests evaluated the thermal resistance and solar reflectance of SVG-insulated walls. Subsequently, a three-month outdoor experiment in Hong Kong measured surface temperatures, heat gains, and power outputs. Results show that SVG-insulated walls significantly reduce inner surface temperatures, delay peak wall-related cooling loads, and cut indoor heat gains by 35 %–52 % compared to concrete walls, thus effectively lowering cooling demands in hot climates. The study also assesses the electrical performance of c-Si-based and CdTe-based SVG-insulated walls, revealing insights into PV generation and degradation of BIPV technologies. By offsetting electricity demand through on-site generation, SVG-insulated walls reduce reliance on grid energy. For example, on typical sunny days, c-Si-based SVG-insulated walls reduced grid electricity consumption by 74 %–79 % compared to insulation walls. Overall, this research provides empirical data and practical guidance for optimizing the design and application of BIPV and building insulation technologies in hot climates.