Open Access

REVIEW

Optical, Thermal, and Electrical Properties of Building-Integrated Photovoltaics (BIPV): A Critical Review

Haotian Yang¹, Lin Lu^1,2,*

1 Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
2 Research Institute for Sustainable Urban Development (RISUD), The Hong Kong Polytechnic University, Kowloon, Hong Kong, China

* Corresponding Author: Lin Lu. Email:

Energy Engineering 2026, 123(10), 1 https://doi.org/10.32604/ee.2026.083071

Received 28 March 2026; Accepted 08 May 2026; Issue published 30 August 2026

Abstract

Building-integrated photovoltaics (BIPV) has attracted growing attention due to its promising applications in modern buildings. By serving as components of the building envelope, BIPV avoid competing with land use and facilitates net-zero energy buildings in the face of the current energy crisis. In addition to power generation, BIPV alters the energy-related properties of buildings. Appropriate daylighting and effective management of heat gains can reduce lighting, cooling, and heating loads, helping to balance energy production and consumption. This review examines the optical, thermal, and electrical behaviors of BIPV systems and their impacts on building energy efficiency. The discussion of optical properties emphasizes the visible spectrum, solar PV response spectrum, and atmospheric window. Thermal considerations focus primarily on BIPV/thermal (BIPV/T) systems and on the regulation of solar heat gain coefficient (SHGC) and U-value. Electrical performance is analyzed with respect to cell coverage ratio, window-to-wall ratio (WWR), and shading effects. Finally, key barriers to widespread BIPV deployment are identified, including challenges in architectural integration, cost-effectiveness, and aesthetic design. This work aims to provide a useful reference for researchers and practitioners engaged in BIPV design.

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Keywords

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