Evolution and comparation of thermal environment to asymmetric large-span greenhouse with insulation quilt in various service states

Compared with traditional Chinese solar greenhouses, the asymmetric large-span greenhouses (ALSG) were more convenient for mechanized planting and have higher land utilization efficiency. However, service state of the full coverage insulation quilt directly determined thermal environment of the ALSG. Therefore, in this paper, an innovative vertical multi-physical field environment simulation experiment device was developed to measure the thermal performance parameters of the insulation quilt under three states, that was dry, wet, and icing. Furthermore, by combining numerical analysis with field test, evolution and comparation of the greenhouses thermal environment was revealed. Eventually, method for selecting insulation quilts based on the minimum night-time temperature requirements of the crop was established. The results showed that heat transfer coefficients of the insulation quilt in the dry, wet and icing states were 0.95 W/(m2·K), 2.21 W/(m2·K) and 1.75 W/(m2·K), respectively. The reliability of the model was verified, and the influence of insulation quilt with different service states on thermal environment of the ALSG was clarified. Based on the insulation quilt selection method, the heat transfer coefficient should be 0.60–1.10 W/(m2·K) to the ALSG. It provided a reference basis for construction and application of the ALSG.