Optimizing the tilt angle of kinetic photovoltaic shading devices considering energy consumption and power Generation— Hong Kong case

Abstract

Photovoltaic Shading Devices (PVSDs) serve as integral components of Building-Integrated Photovoltaics (BIPV), fulfilling both architectural shading functions and supplying on-site renewable energy to buildings. Previous studies have primarily focused on the energy efficiency of PVSDs in single-story or low-rise buildings, often overlooking the thermal hotspot effects caused by the shading of upper devices on lower ones in multi-story settings, which significantly impairs the efficiency and lifespan of the PV systems. This study focuses on a residential high-rise in Hong Kong, where a kinetic PVSD was designed alongside three innovative control strategies aimed at minimizing energy consumption and optimizing photovoltaic efficiency. Results indicate that in Hong Kong’s context, a ratio of PV panel width to the vertical spacing of adjacent PVSDs below 1:10 prevents vertical shading between devices. Moreover, setting the PVSDs at a constant optimal angle of 65° throughout the year, adjusting to optimal monthly angles, or employing real-time angle optimization can reduce energy consumption by 25%, 31.9%, and 36.5%, respectively, compared to units without PVSDs. Furthermore, the hourly control strategy generated 6.4% and 11.4% more electricity than the monthly and yearly control strategies. The kinetic photovoltaic solar devices (PVSD) and the diverse control strategies discussed in this research provide valuable practical insights for the integration of building-integrated photovoltaics (BIPV) on urban facades in densely populated cities. These findings also support the advancement of zero-carbon building practices in high-density environments.