Experimental research on environment and heat preservation effect of solar greenhouse: type Liaoshen Ⅰ

Northeast China energy-saving type Liaoshen Ⅰ solar greenhouse is very well equipped, which brings about several achievements especially on the aspects of lighting, heat preservation and the design of structure. An experiment was done in the type Liaoshen Ⅰ solar greenhouse to measure the temperature, illumination, moisture, heat environment and the function of heat preservation. The results showed that, during the winter season, the lowest temperature in the greenhouse reaches 8.2℃, the highest one is 32.3℃, and the average is one 15.0℃ while the mean temperature outdoors is -17.3℃; the temperature difference between inside and outside reaches 32.3℃. The average temperatures of different depths of soil (1, 3.5, 50 cm below the earth surface) are basically the same, which are 14.2℃, 14.2℃ and 14.8℃, respectively. The average accumulation of heat of the wall in the greenhouse reaches 8.35 MJ/(m²·d), the release energy to the inside of the greenhouse attains 1.69 MJ/(m²·d) at night, and the energy dissipation to the outside reaches 2.61 MJ/(m²·d). The average accumulation of heat of the back roof reaches 3.45 MJ/(m²·d), the release energy to the inside of the greenhouse is relatively low, only 0.07 MJ/(m²·d); while the energy dissipation to the outside is relatively high, which reaches 2.04 MJ/(m²·d) in average. Soil heat-discharge analysis shows that under soil surface 5 cm, the mean accumulation of heat can attain 0.75 MJ/(m²·d) in the daytime, but at night the energy dissipation reach 0.48 MJ/(m²·d). However the energy dissipation, of the front slope is comparatively higher than that of the back roof, which reaches 7.55 MJ/(m²·d).