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  • Experimental study of the t...
    Guan, Yong; Meng, Qi; Ji, Tianxu; Hu, Wanling; Li, Wenlong; Liu, Tianming

    Energy (Oxford), 02/2023, Volume: 264
    Journal Article

    Solar greenhouses are agricultural facilities that use solar energy for growing vegetables. The thermal characteristics of a solar greenhouse wall have an important influence on the creation of the microclimate in the greenhouse and improving the heat storage capacity of the wall materials can prevent freezing damage of greenhouse crops. To increase the temperature of the internal temperature stabilisation layer and the heat storage and release characteristics of the wall, a novel greenhouse wall with micro-heat pipe arrays (MHPAs) and phase-change materials (PCMs) was proposed, and an experimental greenhouse with the proposed wall and an ordinary greenhouse were built in this study. The thermal performance of the greenhouse wall and the improvement effect on the greenhouse microclimate for typical weather conditions were analysed using dynamic evaluation indices, such as the air temperature, the inner surface temperature of the experimental wall, and the heat storage and release rate of the greenhouse wall. The combined use of MHPA and PCM solves the problem of the heat transport bottleneck caused by the low thermal conductivity of PCM and the traditional wall temperature stabilisation layer, and effectively increases the amount of heat stored in the wall, thereby ensuring the growth of crops at night. For typical days, the average total heat storage of the experimental wall was 18.89 MJ/m3, while that of the ordinary wall was 9.67 MJ/m3 (an increase of 95.35%). The average total heat release was 17.58 MJ/m3, while that of the ordinary wall was 8.95 MJ/m3 (an increase of 96.42%), which led to an increase in the air temperature during the night and provided an environment suitable for the crop growth. •A novel greenhouse wall incorporating MHPAs and PCMs has been developed.•Two small-scale solar greenhouses for comparative experiment analysis were built.•The use of MHPA well solves the problem of a thick temperature stability layer in the traditional wall.•The effectiveness of the MHPA greenhouse in improving the thermal environment has been verified.