Vertical bifacial solar photovoltaic balustrades for low-carbon buildings : a numerical analysis of energy performance

Abstract

Bifacial solar photovoltaic (PV) technologies are increasingly prominent in building applications due to their capacity to capture solar radiation on both sides. However, traditional bifacial PV systems face practical challenges in building integration, such as shading and structural load constraints. This paper introduces an innovative bifacial PV balustrade system that integrates vertical bifacial PV modules on rooftop edges, minimizing shading and enhancing cost-effectiveness for greater building applicability. A multi-physics numerical analysis was conducted to evaluate energy performance, considering parameters such as roof albedo, ground clearance, reflective width, and module orientation. Results indicate that roof albedo and module orientation are critical to both power output and bifacial gain. High roof albedo and east/west orientations enhance power output, while a north-facing configuration maximizes bifacial gain. A nationwide analysis reveals that PERC technology achieves an annual power output of 732–1786 kWh/kWp and a bifacial gain of 1.16–1.47, while HJT technology enhances these metrics by approximately 17 % and 30 %, respectively. Moreover, an optimized setup using HJT modules, reflective surfaces, and a roof albedo of 0.9 yields a maximum bifacial gain of 2.04. This study underscores the potential of high-performance bifacial PV modules as rooftop balustrades and provides valuable insights into their energy performance.