Annual performance analysis of a dual-air-channel solar wall system with phase change material in different climate regions of China

Abstract Applications of phase change material (PCM) in buildings have significant energy-saving potential. In this work, a dual-air-channel solar wall system with PCM is proposed, which has the following main functions: electricity generation, hot water supply, passive indoor space heating and ventilation cooling. Continuous experimental tests were conducted through two hot-box rooms in Hefei to confirm the energy saving effects of the system. Mathematical model of the system is established and validated against the experimental results. With the validated model, the annual performance of the system in three selected cities (Urumqi, Beijing and Hefei) is investigated. Annual electricity generation and average electrical efficiency of the three cities are 179.67 kWh, 179.21 kWh, 119.28 kWh and 11.22%, 10.67%, 11.06%. Annual energy saved are 863.24 kWh, 770.53 kWh and 576.43 kWh. Parametric analyses are also conducted. Proper increase of PV coverage is beneficial to the comprehensive performance of the system. Decrease of the thickness ratio of the outer and inner channel and increase of depth-to-width ratio of the channel can both enhance the thermal performance in heating season. The selection of melting temperature and thickness of PCM should be based on the weather condition of the region where the system is applied.