一种具有新型传热结构的太阳能相变蓄热系统的传热与能效评价

Abstract To address the intermittent and unstable characteristics of solar energy, the combination of a solar energy system and a phase change latent heat storage unit is a promising solution. In this study, a new sandwich spiral structure is designed for a solar phase change heat storage system for residential applications. First, the influence of this structure on the internal temperature field of the latent heat storage unit is studied. Second, the effects of different radiation areas and different weather factors on the solar phase change heat storage system are compared. Finally, thermodynamic analysis of the system is carried out. The experimental findings show that the melting rate of the sandwich spiral structure is 45% of that of the double spiral structure of the same size and that the melting rate is uniform without obvious melting slow phase transition region. The solar radiation area is larger, the heat storage in the constant-temperature water tank is greater, and the temperature rise is faster. Among the influences of weather factors (solar irradiance, temperature and relative humidity) on the system, when the solar radiation intensity and temperature are stable, the relative humidity influences the solar phase change heat storage system. The overall performance of the system is evaluated. The energy efficiency of the system is 38.5%, and the exergy efficiency is 8.3%. The evaluation of the thermal performance of solar phase change heat storage systems is valuable and can provide theoretical guidance and a design basis for solar water heaters in residential applications.