Comparative Study On The Variation Regularity Of Temperature And Light Conditions Of Different Structure Solar Greenhouses In Winter In Alpine Regions

With the development of facility horticulture industry,the solar greenhouse needed for overwintering production in high and cold areas is more and more strong.The solar greenhouses of different structures in the alpine regions represented by Heilongjiang Province are displayed,but the effect of their use is uneven.What type of structure of the temperature and light performance of solar greenhouse meets the demand of winter production in alpine regions.Therefore,this study selects three kinds of solar greenhouses with different front roof angle,different rear roof angle,different ridge height,different front roof overlay(single layer single cover,double layer double cover),different envelope walls(insulation and storage materials,different thickness),they are single layer single cover red brick greenhouse(No.1),double layer double cover quilt greenhouse(No.2),double layer double cover composite wall greenhouse(No.3),analyzed of structural parameters of three different structures of greenhouse,determined the actual temperature and light characteristics of the use processand finally comparative analysis.The main results are as follows:(1)In terms of lighting,comprehensive analysis shows that the ouble film double cover quilt greenhouse and double membrane double cover composite wall greenhouse is better than single-membrane red brick greenhouse;In terms of insulation,double membrane double cover composite wall greenhouse is optimal;In terms of heat storage,single-membrane red brick greenhouse is optimal.(2)The change rules of soil temperature in the actual use of three different structures of solar greenhouses is:During the trial,the soil temperature double film double cover quilt greenhouse was below 5 ℃,so it was not suitable for winter production without heating,while the soil temperature double membrane double cover composite wall greenhouse was always kept above5℃.The western of Three greenhouses have the lowest soil temperature when sunny,the northern soil temperature is the lowest on cloudy days.(3)The change rules of air temperature in the actual use of three different structures of solar greenhouses is:In sunny weather conditions,the lower part temperature of three greenhouses(0.5m from the ground)is the lowest in the west;the lower part temperature of the single-membrane red brick greenhouse is the lowest in the west,the north of double film double cover quilt greenhouse and double membrane double cover composite wall greenhouse(same soil temperature).The temperature in the upper part of the three solar greenhouses with different structures(1.5m from the ground),in sunny weather conditions,the temperature difference between all parts of single-membrane red brick greenhouse and double film double cover quilt greenhouse is not significant,the highest temperature in the middle of double membrane double cover composite wall greenhouse,under cloudy weather conditions,the upper part temperature regularities of distribution of the three greenhouses is the same as the lower part temperature,but the temperature is higher than the lower part temperature.(4)The change rules of light in the actual use of three different structures is as follows:The change of light in the solar greenhouse tends to decrease first and then increase later.On sunny days,the southern light intensity of three greenhouses is the highest,which can meet the growth demand of conventional leafy vegetables,and the light intensity of 5h meets the requirements of fruits and vegetables;the overall light intensity of cloudy days is significantly lower than that of sunny days,and the light intensity of double film double cover quilt greenhouse and double membrane double cover composite wall greenhouse only 3h meets the demand of leafy vegetables.(5)The change law of relative humidity in the actual use of the three different structure solar greenhouses is as follows: under typical weather(sunny day,cloudy day),the relative humidity of the three greenhouses is the highest in the south,the lowest in the north,and the change law of relative humidity of the three greenhouses is the same.(6)The insulation performance of the double layer composite wall greenhouse is optimal on the basis of reasonable insulation ratio.In the reasonable front roof angle,the rear roof angle range,the rear roof horizontal projection is small,the greenhouse lighting conditions are the best.Under cloudy weather conditions,The front roof angle of the largest greenhouse lighting uniformity is the highest.