Thermal performance of a closed collector–storage solar air heating system with latent thermal storage: An experimental study

The collector–storage solar air heating system has huge application potential in many fields. Traditional collector–storage solar air heating systems have been applied in related fields, but improving the temperature of phase change materials (PCMs) quickly is difficult because these systems are open. On the basis of a literature review, this study proposes a closed collector–storage solar air heating system (CCSSAHS) that connects a solar air collector and a latent thermal storage unit in series to form a closed loop, thus avoiding the wastage of high-quality energy. The thermal storage performance of CCSSAHS under different meteorological parameters and volume flow rates was studied experimentally. The heat losses of the various components of this system were analyzed comprehensively. Results showed that CCSSAHS can quickly increase the temperature of PCM. On February 16, 2018 and July 26, 2018 the temperature of PCM increased to 50 °C after 126 and 48 min, respectively. The highest temperature of PCM that CCSSAHS could achieve was 68.52 °C within 132 min. The heat loss proportion of the solar air collector was between 55.87% and 71.05%. These findings are expected to provide a basis for the design and optimization of similar systems.