A novel building integrated photovoltaic/thermal wall for hot water-electrical power co-generation

Building integrated photovoltaic/thermal (BIPV/T) technologies offer a promising approach for building envelopes to improve both aesthetics and sustainability. Generally, traditional BIPV/T systems operate with open-loop cooling water systems that rely on pumps for circulation and limit flexibility. This study proposed a novel natural circulating-based BIPV/T system, with closed-loop cooling water systems. With the system, a transient model was developed. Firstly, this model was implemented in Chengdu to explore the impact of design parameters, include water layer thickness, pipe diameter and flow rate of feedwater, on the system. After parameter analysis, the optimal water thickness of 8 mm, feedwater flow rate of 5 kg/h, and pipe diameter of 2 cm were identified. Then, to further explore the feasibility of this system in different regions of China, energy-saving simulations of the system were conducted among 371 cities in China. The results reveals that the BIPV/T system is particularly effective in warmer climates, such as southern China, where energy harvesting efficiency can reach 0.56. While in severe cold regions, such as Qinghai–Xizang Plateau and northeastern China, the energy harvesting efficiency is merely about 0.3. This study highlights the promising potential for the novel BIPV/T systems to enhance energy efficiency in suitable environments.