| Solar greenhouse is the important agricultural facilities because of its satisfied the needs of crop production in winter.It can not only solve the problem of lack of fresh fruits and vegetables supply in the north of China in winter,meanwhile,it can use solar energy as power source which drives the greenhouse production that can reduce energy consumption.It is benefit to our country's social,economy and ecology.Inner Mongolia is located in the north of China,with sufficient sunlight,is one of the ideal areas for the development of solar greenhouse industry.But,the climate is poor in winter.Traditional solar greenhouse often coverd external thermal insulation blanket,but in that way,blanket is easily affected by the severe environment.The servce life and the weight of the blanket is change,which can result to performance decline and structure unsafety.Thermal insulation and heat storage of solar greenhouse is not only the research focus of greenhouse design theory,but also the important guarantee of production practice.Based on the Inner Mongolia region climate conditions and greenhouse design theory,the facility agriculture research group of Inner Mongolia agricultural university has designed the blanket-inside solar greenhouse with the structure optimized.However,the blanket-inside solar greenhouse also has a lot of shortcomings in practice.Therefore,firstly,comparing the light condition between normal solar greenhouse and blanket-inside soalr greenhouse,the lighting characteristics in solar greenhouse were defined.Secondly,solar radiation model has been established.The factors of luminous environment had been analylzed by the solar radiation model.Finally,the indoor environment of four types blanket-inside solar greenhouse had been tested,the results of the research can provide theoretical reference for solar greenhouse structure designed and environmental controlled.The main conclusions are as follows:1)Compared with the normal solar greenhouse,the light environment of the blanket-inside solar greenhouse was significantly improved in different weather conditions and spatial distribution.On a sunny day(2015.1.10),compared with the normal solar greenhouse,the average solar radiation,the average lighting rate and the solar radiation accumulation of the blanket-inside solar greenhouse can be increased by 9.7%?16.8%,11.11%?16.89%and 9.82%?17.06%,respectively.On a cloudy day(2015.1.6),the average solar radiation,the average lighting rate and the solar radiation accumulation can be increased by 14.4%?17.7%,15.22%?19.64%and 17.28%?17.51%,respectively.2)A light environment model of the blanket-inside solar greenhouse was developed.The coefficient of determination R~2 of the was high,range from 0.89 to 0.96,and the accuracy of simulating the solar radiation of the blanket-inside solar greenhouse was high.According to the model calculation,the light transmittance of solar greenhouse was higher in the east direction in the morning than in the west direction on the winter solstice day,while it was opposite in the afternoon.The difference of the ground solar radiation in the greenhouse in different orientations is small,mainly due to the time node when the greenhouse wall received the maximum solar radiation.The time in the south orientation appeared at noon,appeared later at noon in the west orientation,and appeared earlier at noon in the east orientation.There were no significant differences among the solar radiation accumulation of ground and wall in same azimuth change.3)Through the solar radiation model calculation,the factor that the blanket rolled and stoped at somewhere was analysed.The results showed that the less the blanket rolled,the less solar radiation received,especially the wall got less.The solar radiation accumulation can be reduced for 11%?78.53%with the position of the blanket changed.4)Compared with the other three greenhouses,G3 was more prominent in the thermal environment building.Results a month(2016.12.15?2017.1.15)showed that the air temperature of G1 rapidly sank at night,while G3 slowly sank.On couple of sunny days(2017.1.11 9 a.m.?2017.1.14 9 a.m.),the average night air temperature of G1,G2,G3and G4 were 10.5?,12.4?,13.1?,11.9?.On couple of bad days(2016.12.22 9 a.m.?2016.12.24 9 a.m.),the average night air temperature of G1,G2,G3 and G4 were8.5?,10.4?,11.1?,9.3?.5)During a week(2017.1.1?1.7)the four solar greenhouses worked,the relative humidity of each solar greenhouse exceeded 90%at night.And the average soil temperature inside G1,G2,G3 and G4 in 20 cm depth were 13.7?,16.8?,17.5?and14.2?,respectively.6)The wall temperature inside G1,G2,G3 and G4 in 20 cm depth rapidly changed.On a sunny day(2017.1.2 9 a.m.?1.3 9 a.m.),the average wall temperature inside G1,G2,G3 and G4 were 13.4?,16.3?,17.4?and 11.9?,respectively.On a cloudy day(2017.1.6 9 a.m.?1.7 9 a.m.),the average wall temperature inside G1,G2,G3 and G4 were 10.9?,12.9?,14.2?and 10.8?,respectively.The average wall temperature inside G1,G2 and G3 were stabilization in 40 cm and 80 cm depth on a sunny day,while which were just stabilization in 80 cm depth.And the heat release still occurred in 40 cm depth of wall inside G1,G2 and G3 on a cloudy day.8)The construction cost of per square meter of G1,G2,G3 and G4 is 284.7RMB,293.4 RMB,317.7 RMB and 236.9 RMB,respectively.Either the best thermal environment G3 has,or the highest cost.G4 has the lowest cost and slightly better thermal environment than G1,but the heat storage effect of the wall is poor. |
PDF Full Text Request