Exploring Air-PVT for buildings in cold climates: Experimentally validated energy system modeling

Air-based Photovoltaic Thermal (Air-PVT) technology can be considered as a low-cost, renewable energy alternative for building applications, due to its dual supply of both heat and electricity. Its technical advantages, such as lack of leakage, freezing and safety risks, further emphasize its practical potential for building integration. In this study, the goal is to address a specific and persistent research gap relevant to Nordic climates: the limited number of validated, real-life use cases of air-PVT systems integrated into existing multifamily residential buildings operating under cold-climate conditions with relatively limited solar resources. To do this, alternative approaches of Air-PVT integration into buildings are explored and the operational benefits are evaluated and compared to a building with a regular solar panels, in Nordic climate conditions. Specifically, the synergies of Air-PVT with ventilation and domestic hot water systems are explored through energy simulations with the software package TRNSYS, validated by measurements from the experimental testing of an Air-PVT prototype, while heating and ventilation data were collected from a real building in Stockholm, Sweden. Results suggest that thermal energy savings of 16% and 6.6%, for a building with Air-PVT compared to a building with standard PV, are attainable for the ventilation and domestic hot water systems, respectively. Thermal power peak shaving for district heating demand averaged at 11% for the duration of a season, reaching up to 50% on specific days. Additionally, other critical factors for applications in cold climate conditions were evaluated, such as the effect of: frost formation in Heat Recovery Units, massflow rate through individual collectors, the collectors inclination as well as building location on the combined Air-PVT building operation. The findings demonstrate that the implementation of Air-PVT in buildings is a viable energy solution. Air-PVT installations can provide additional benefits for building operation, than regular photovoltaic installations and should be considered in energy renovations. • Experimental Air-PVT and real building operation data utilized in energy simulations. • Air-PVT combined with HRV ventilation provides 16% thermal energy savings. • Air-PVT combined with DHW system provides 7% thermal energy savings. • Thermal Peak Shaving for DHW system averaged at 11%, with maximum up to 50%. • HRV frost formation, Air-PVT massflow and building location effects evaluated.