Numerical study of thermal performance of phase change material energy storage floor in solar water heating system

The conventional solar heating floor system contains a big water tank to store energy in the day time for heating at night, which takes much building space and is very heavy. In order to reduce the water tank volume even to cancel the tank, a novel structure of integrated water pipe floor heating system using shape-stabilized phase change materials (SSPCM) for thermal energy storage was developed. A numerical model was developed to analyze the performance of SSPCM floor heating system under the intermittent heating condition, which was verified by our experimental data. The thermal performance of the heating system and the effects of various factors on it were analyzed numerically. The factors including phase transition temperature, heat of fusion, thermal conductivity of SSPCM and thermal conductivity of the decoration material were analyzed. The results show that tm and kd are the most import influencing factors on the thermal performance of SSPCM floor heating system, since they determine the heat source temperature and thermal resistance between SSPCM plates and indoor air, respectively. Hm should be large to store enough thermal energy in the day time for nighttimes heating. The effects of kp can be ignored in this system. The SSPCM floor heating system has potential of making use of the daytime solar energy for heating at night efficiently in various climates when its structure is properly designed.