Optimising Building Integrated Photovoltaic Thermal for Retrofitting

Key results

It has been demonstrated that air-based BIPVT systems can be effective in supplying heat and electricity during cooler weather. However, the cooling capacity available from night time radiative cooling processes during warm nights was found to be limited.

Theoretical simulation and testing of experimental prototypes of BIPVT-PCM integrated systems showed that appropriate integration of PCMs with BIPVT can improve the ability of a BIPVT system to provide useful heating and or cooling to a building, potentially lowering the life cycle cost of BIPVT. However, the overall performance of the integrated systems is strongly dependent on the PCM types, PCM phase change temperature, storage design, energy flow control and optimisation, as well as climatic conditions.

Advanced control strategies and algorithms should be developed for real-time control and optimisation of air-based BIPVT systems. This includes optimising of fan speeds as a function of dynamic weather conditions and scheduling to meet the requirements of householders. The leakage related to BIPVT components, specifically in dampers, can significantly affect the overall performance of the BIPVT system and should be properly addressed during the design, installation and commissioning phases of a project. The design of BIPVT systems should be optimised to best meet the building demand for heating, cooling and electricity.

The air-based BIPVT modules were found to have a moderate payback period, typically greater than most conventional rack-mounted PV systems. The current value of BIPVT systems is tied not only to their energy production capabilities, but also to the improved aesthetics and functionality that they bring to a building as compared to conventional rack-mounted PV systems. Improved design and manufacturing efficiency of BIPVT will help bridge the economic gap with respect to the relatively mature market for rack-mounted PV systems.