Multivariate optimization of mechanically ventilated photovoltaic double-skin façade system for the cold conditions of composite climate zone

Assessing the performance of a multi-storey building equipped with a mechanically ventilated photovoltaic-double skin façade (photovoltaic-DSF) system during cold weather conditions is crucial. This is because the demand for heating in buildings rises as outdoor temperatures decrease. This study formulates and verifies mathematical models to evaluate the energy performance of a building integrated with a mechanically ventilated photovoltaic-double skin façade (photovoltaic-DSF) system in Jaipur’s cold climate, which is part of India’s composite climate zone. The system was installed and observed during the winter months (December to February). The experimental design utilised a Taguchi L25 orthogonal array, considering variables such as air cavity thickness, air velocity, and photovoltaic (PV) panel transparency. Based on experimental findings, multiple linear regression analysis was used to predict three key performance metrics: The solar heat gain coefficient (SHGC), photovoltaic panel electrical output, and indoor daylight illuminance, all as influenced by the design parameters. The analysis of variance (ANOVA) confirmed the statistical significance of these relationships, and the model demonstrated a strong correlation with field measurements (R2 > 0.90), validating the accuracy of the developed mathematical correlations. The analysis reveals that a photovoltaic DSF system integrated into a multi-storey building, featuring a photovoltaic panel with 50% transparency, an air velocity of 5 m/s, and a 50 mm air cavity, achieves maximum energy performance under cold climate conditions in a composite climate. These insights can help in designing energy-efficient photovoltaic-DSF systems specifically optimised for winter conditions in composite climate zones.