Perspectives and review of photovoltaic-thermal panels in net-zero energy buildings

This forward-looking perspective article presents a status overview of solar photovoltaic-thermal (PVT) panels in net-zero energy buildings from various points of view and tries to picture the future of the technology in this framework. The article discusses the pros and cons of PVTs' state of practice, design developments, and integration possibilities. Investigations show that for sufficiently benefiting from the potential of PVT panels for smart buildings, some major challenges such as high investment cost and lack of two-way interaction with district energy systems must be addressed. In addition, some of the most promising research focuses of the field are discussed as the further possible solutions for advancing the state-of-the-art in this context. These are finding feasible ways to reduce the cost of PV cells, downsizing battery and heat pumps based on optimal two-way interactions with thermal and power grids, tri-generating via enabling the panel for passive cooling (PVTC), and developing concentrating PVTs and PVTCs. The potential impact of this article's advice for future research may be an increased motivation of buildings to be furnished by such solar-based energy systems and thus a higher contribution of PVT panels in net-zero and smart energy buildings.