Study on photo pyrolysis coupling and performance of columnar phase change energy storage system based on composite phase change materials for Chinese solar greenhouse

To improve the phenomenon of uneven light environment and low indoor temperature at night caused by crop and structure occlusion in Chinese solar greenhouse, this study proposes a columnar energy storage device filled with composite phase change materials and combined with a reflecting film based on the full spectrum utilization of solar energy, which is placed on the north wall surface of Chinese solar greenhouse to comprehensively regulate the photothermal environment and a control greenhouse without heating is also set up for comparison. After testing, at 50 °C and an optical path length of 50 mm, the composite phase change materials with a concentration of 0.001 % nanoparticles have an average transmittance of 66.7 % in the photosynthetically active radiation band, and an average sum of absorption and reflectance of 79.8 % in the near infrared spectrum band. The greenhouse experiment results showed that the average growth factor index G of plants in the experimental greenhouse increased by 17.53 %. The average air temperature in the greenhouse increased by 1.70 °C at night. During the experiment, the average heat collection efficiency of columnar energy storage devices was 40 %. This study provides a new approach for efficient greenhouse production using full spectrum solar energy utilization.