Novel Hybrid Solar Photovoltaic/Thermal (PV/T) Collectors and Thermal Storage and Their Integration into Building Energy Systems for Cold Climates

This dissertation focuses on integrating novel hybrid solar photovoltaic/thermal (PV/T) collectors and thermal storage into building energy systems for cold climates. The research comprises three papers that investigate various aspects of these systems. The first study compares the performance of four different solar-based systems for domestic hot water (DHW) production in Canada's residential sector. A microchannel (MC) solar thermal collector and a microchannel-based hybrid PV/T collector, utilizing microchannel heat exchangers, were fabricated and then modelled and simulated using TRNSYS software. Integration with a water-to-water heat pump (HP) improves the systems' efficiency and solar fraction. The results show that the microchannel solar thermal and PVT-HP system achieves the highest annual solar fraction, outperforming conventional solar thermal and PV-resistance systems. It performs superior in cold climates, with a 10% to 35% higher solar fraction during winter. Moreover, the MC-based systems demonstrate less sensitivity to collector tilt angles, which is more suitable for facade integration in high-rise buildings. There are some limitations and potential enhancement opportunities for the first study that influenced the system's efficiency. Another study is conducted to enhance the thermal storage system to improve the system's efficiency. The second study proposes an innovative approach to building-integrated thermal storage using insulated concrete form (ICF) foundation walls in cold climates. The surplus solar thermal energy is stored within the high thermal capacity of the ICF walls. Coupled with a water-to-water heat pump, the ICF walls and solar thermal collectors fulfill the combined space and DHW heating demand by up to 72%. Simulation results reveal that the ICF-based system achieves a higher solar fraction than systems with large water tanks. Incorporating PVT collectors increases the overall solar fraction further to 82%. The proposed ICF-based systems perform optimally at high tilt angles and are also suitable for vertically mounted solar systems in high-rise buildings with limited roof areas. As the solar collector has a significant role in the system’s total efficiency, a new type of PVT collector is being studied to enhance the system’s efficiency. The third study focuses on the design of a cost-effective and efficient air-based PV/T collector. The proposed PVT utilizes an industrialized heat exchanger, GRIPMetal or GM, as the absorber plate. The GM plates, consisting of spikes and cavities, improve the convective heat transfer coefficient in the air channel, resulting in significant enhancements in electrical and thermal efficiencies. Through numerical modelling and experimental validation, it is demonstrated that the GM-based PVT collector reduces the PV panel temperature and compensates for the extra pressure drops, leading to higher overall system efficiency. A maximum of 25% total efficiency enhancement is observed for GM-based PVT collectors over flat plate PVT collectors. The optimal configuration involves a low airflow rate, a narrow air channel, and the largest available GM spikes. These findings contribute to developing cost-effective and efficient air-based PV/T collectors that can be integrated with HP-based systems to provide building heating load.