Feasibility investigation of spectral splitting photovoltaic /thermal systems for domestic space heating

The building-integrated solar energy system is an important technology to achieve carbon neutrality in the building sector. However, traditional solar energy systems, such as PV modules, solar thermal collectors, and PV/T systems, are aimed to maximize electricity or heat yield separately, without considering flexible heat/electricity harvesting mode switching. In this study, a novel spectral splitting PV/T system, in which the silver nanofluids cover the surface of PV modules, is proposed to respond to a changeable outdoor environment. The transient numerical model is developed using Matlab software and validated with experiment results, and the mean relative percentage error of thermal efficiency is 6.43%. The feasibility of spectral splitting PV/T systems for domestic space heating is investigated. The influences of outdoor factors and operating parameters on the performance of PV/T systems are discussed for better regulating PV/T systems. Additionally, a flexible control strategy is proposed to achieve the goal of a 45 °C outlet temperature and enhance the overall efficiency. The results show that the daily mean energy harvesting in Zhengzhou, Beijing, and Harbin during the whole heating season can reach 2.69 MJ, 5.01 MJ, and 3.12 MJ with a collection area of 0.61 m².