A double-glazed solar air-phase change material collector for nocturnal heating: Model development and sensitivity analysis

Abstract

Solar air collector with latent heat thermal energy storage (LHTES) is widely used in space heating. However, the thermal efficiency of the solar air collector with LHTES is low when the heat is stored during the day and released at night. The method of optimizing thermal efficiency by studying the influence of design parameters on thermal performance is yet to be explored. In this study, a numerical model is developed and validated to investigate the thermal performance of the double-glazed solar air- phase change material (PCM) collector. The heat storage (in daytime) and release (at night) process of the solar collector under different design parameters are studied by orthogonal test. The results show that the heat storage process is mainly affected by the type of PCM, while the heat release process is affected by the air velocity of air channel, length-width ratio of the collector, height of the air channel and the type of PCM. Then, range and variance analysis are applied to analyze the degree of influence of air velocity of air channel, length-width ratio of model, height of air channel, and type of PCM on the outlet parameters and efficiencies of the double-glazed solar air-PCM collector. Finally, according to the degree of influence of each factor on the indexes, the optimization scheme of the collector performance is obtained. When the airflow rate is 64.80 m3/h, the average temperature rise at night is 9.54℃, and the heat exchange efficiency is 66.41%, and solar thermal efficiency is 34.10%.