Developing a comprehensive method for integrating the thermal, optical and electrical properties of a complex fenestration system into building simulation software for building performance characterisation

To enhance energy conservation, indoor comfort, and mitigate greenhouse gas emissions in buildings, the design of glazed facades and window systems has seen substantial improvements. These enhancements result in increased thermal resistance while maintaining access to daylight and incorporating the use of renewable energy. Some of these glazing systems possess complex structures and PV cells, which present challenges in characterising their thermal, optical, and electrical properties for utilisation in building simulations. In this research, a comprehensive model has been developed to accurately predict the thermal, optical, and electrical properties of complex PV glazing systems, and a workflow has been developed to yield detailed thermal and energy performance predictions of these systems when applied to buildings. Using this approach, the thermal properties of complex PV glazing systems are obtained from a validated Computational Fluid Dynamics (CFD) combined ray-tracing model. The recursion algorithm, along with ray-tracing calculations, is used to determine their solar-optical properties. Additionally, a PV modelling algorithm has been developed to estimate their power output. All of these properties can be integrated into building simulation software, such as EnergyPlus, to assess the thermal and energy performance (e.g., solar heat gain coefficient and power output) of the complex PV glazing system when applied to a building. In this study, a Crossed Compound Parabolic Concentrator Photovoltaic (CCPC-PV) window is selected as an example of the complex PV glazing system, and a case study is conducted to investigate the annual energy performance (heating, cooling, lighting and power generation) of a typical cellular office room using the CCPC-PV window. The results demonstrate that the comprehensive model, simulating the CCPC-PV window within building simulation software, accurately characterises its thermal, optical, and electrical properties under London's climatic conditions. This high level of accuracy, with deviations of less than 5%, is of significant importance when simulating building energy performance with advanced glazing systems. Furthermore, the CCPC-PV window is more suitable for installation with a larger window-to-wall ratio (e.g., 64%), resulting in a 56.86% energy-saving percentage when compared to a similarly structured double-glazed window under London climate conditions.