| Sunlight greenhouse is a kind of renewable energy use method, the characteristics of its simple, economic, energy saving make it become the pillar industries of agriculture and rural economy in north China. However, in summer, because of its characteristic of closed planting, the temperature and humidity in greenhouse always at high quality, which is extremely unfavorable to the normal growth of crop, prone to diseases and insect pests. Cold winter and low temperature is much easy to bring frost damage to crops. The temperature and humidity regulation facilities inside the greenhouse are imperfect, which restricts the sustainable development of sunlight greenhouse. Therefore, this paper on how to efficiently ensure economy sunlight greenhouse of thermal and moisture environment of this problem, would mainly have experiment comparative analysis and simulation study on sunlight greenhouse’s indoor air and soil temperature field based the regulation of the earth to air heat exchanger(EAHE).Firstly, this paper is based on two different sunlight greenhouse named test and control the sunlight greenhouse. According to measured data of different weather conditions in winter and summer, this paper compares and analyzes the temperature and humidity of indoor and outdoor and indoor surface soil temperature, from the results, in winter, benefiting from the EAHE, experimental sunlight greenhouse can assure indoor temperature above 8.9℃, and indoor average temperature higher than the controlled sunlight greenhouse temperature 7℃-8℃, while the lowest temperature of the controlled sunlight greenhouse close to 0℃. The surface soil temperature keep around 15℃ in the experimental sunlight greenhouse, higher than that in the controlled sunlight greenhouse 5℃-7℃, and the range of fluctuation is smaller. In summer, in contrast, with the little outdoor temperature difference of these two sunlight greenhouses, experimental sunlight greenhouse’s indoor surface temperature is obviously lower than that of the control sunlight greenhouse 5℃-7℃. These relevant conclusions proved that the EAHE system in the greenhouse temperature and humidity control is in a positive role.And then, using measured soil temperature and temperature & humidity at different length in a horizontal buried heat exchange tube with various inlet wind speed to prove Wu Shuyuan’s simulation results of EAHE and the best way of dimensionless calculation results are verified.Finally on the basis of the verification results combining with the characteristics of these two sunlight greenhouses, the reasonable physical and mathematical models are set up, using FLUENT15.0 software to build a 3D model of sunlight greenhouse with EAHE system as a whole, and compile a custom function for the user in UDF by using the test results of indoor and outdoor air temperature, horizontal buried heat exchanger tube temperature and soil temperature’s change rule, which were plugged into the solver as the numerical basis and conditions of EAHE system in the sunlight greenhouse. The numerical simulation solved indicates that: in summer, EAHE’s cooling capacity is 7℃ during the day, heating capacity is about 2℃ during the night; In winter, except of the small space closed to the structure, the temperature of air in the sunlight greenhouse can guarantee above 5℃, the crops’ temperature in parts of the area, even can reach 7℃, which can protect crops from being frozen. In this paper, by monitoring the import and export air temperature in the process of solving, it is found that EAHE’s air heating capacity is very limited in the winter, started with up to 6℃, but just 4℃ after being stable, which is much weaker than the ability of cooling air in summer. |
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