Design, development and characterisation of a Building Integrated Concentrating Photovoltaic (BICPV) smart window system

Liu, Xiao; Wu, Yupeng

Abstract

Building Integrated Concentrating Photovoltaic (BICPV) window represents a promising alternative approach for improving the electricity generation of photovoltaic cells when integrated into building windows. As a new concept, BICPV smart window consisting of a switchable thermotropic layer with integrated PV cells offers the potential to simultaneously generate electricity and control solar heat and visible light into buildings. In this study, a BICPV smart window system with a Hydroxypropyl Cellulose (HPC) based thermotropic hydrogel membrane has been developed and characterised. The system was designed with the aid of a validated wavelength-dependent optical model based on a Monte-Carlo ray-tracing technique, where the thermal and optical properties of the thermotropic layer used for the optical model prediction were obtained from experimental measurement. Subsequently, a prototype of the BICPV smart window system has been fabricated and characterised under controlled indoor conditions. From the experiments, it was found that the maximum power output of the BICPV smart window (6 wt % HPC) increases by 17.1% with the membrane temperature increasing from 40°C (the transition temperature) to 54 °C; meanwhile, a 70.9% reduction in the light transmittance is observed. This indicated that the BICPC smart window might potentially reduce the solar heat gain in hot periods and therefore reduce the building energy demand. In addition, the effect of different concentrations of HPC polymer (2, 4 and 6 wt %) on the electrical and optical performance of the system has been investigated.

Citation

Liu, X., & Wu, Y. (2021). Design, development and characterisation of a Building Integrated Concentrating Photovoltaic (BICPV) smart window system. Solar Energy, 220, 722-734. https://doi.org/10.1016/j.solener.2021.03.037

• Journal Article Type: Article
• Acceptance Date: Mar 12, 2021
• Online Publication Date: Apr 15, 2021
• Publication Date: May 15, 2021
• Deposit Date: Mar 19, 2021
• Publicly Available Date: Apr 15, 2021
• Journal: Solar Energy
• Print ISSN: 0038-092X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 220
• Pages: 722-734
• DOI: https://doi.org/10.1016/j.solener.2021.03.037
• Keywords: Building Integrated Concentrating Photovoltaic (BICPV); thermotropic membrane; ray- 28
• Public URL: https://nottingham-repository.worktribe.com/output/5402092
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0038092X21002255