Experiment On The Effect Of Heat Exchange System In The Ground On The Summer Cooling Effect Of Greenhouse

With the increase of research on Geothermal exchange system,its application range has gradually expanded to more fields,especially in the regulation of greenhouse environment.However,most of the current research and applications in this area focus on the warming effect in greenhouses,and there are few studies on the cooling effect.This experiment studied the unfavorable problems caused by high temperature in summer in southern Jiangsu,northern Jiangsu and northwestern regions.The detailed analysis of the inlet and outlet temperature,indoor and outdoor temperature of the geothermal exchange system in the whole area,and finally determined the southern and northern Jiangsu.The greenhouse cooling effect in other areas.The test was conducted in Yangling Solar Greenhouse,Zhangjiagang Plastic Greenhouse,and the large-span greenhouse in Yanghe New District of Suqian City from June to September 2018.The solar greenhouse is 12 m long,spans 10 m,and the rear wall is 3.7m high.There are three treatment methods for the heat exchange system in the ground.The length and width of the plastic greenhouse are 81 m and 7m respectively.The strike is north and south,and the heat exchange system in the ground is set at 3 The treatment method;the large-span greenhouse has a length of 81 m,a span of 24 m and a height of 6.5m.There are six treatment methods in the ground heat exchange system.Each district selects a greenhouse that is consistent with the specifications of the local test greenhouse as a control.The greenhouse is not equipped with a heat exchange system.The fans are turned on and off at 6:00 and 18:00 each day.Determine the soil temperature,the temperature of the inlet and outlet,and the indoor and outdoor temperatures of the greenhouse and the control greenhouse in the buried depth of the heat exchange system in the ground.The final research results are as follows:1.In Yangling area,the geothermal exchange system(pipeline depth 150 cm,fan power 550 kw,pipe diameter 200mm)has the best effect.The temperature drop in the sunny and rainy days respectively reaches 2.46 °C?1.43 °C;the average temperature difference between the inlet and outlet is 10.33 ° C;the ground temperature of the pipeline buried in the range of 25.43 ± 3.6 ° C fluctuations,and the control soil temperature difference of 3.33 ± 3.6 ° C.2.In the Zhangjiagang area,the geothermal exchange system(pipeline depth 100 cm,fan power 550 kw,pipe diameter 200mm)has the best effect,with an average temperature of 4.3°C on a sunny day and an average temperature of 2.5°C on a rainy day;the average temperature difference between the inlet and outlet is 6.17°C;The deep ground temperature fluctuated within the range of 26.99±1.67°C,which was 2.76±1.67°C from the control soil temperature.3.In the Yanghe area,the geothermal exchange system arranged along the length of the greenhouse(pipe depth 60 cm,fan power 550 kw,pipe diameter 300mm)has the best effect,with an average temperature drop of 2.52°C on sunny days and an average temperature drop of 0.85 °C on rainy days;average of inlet and outlet The temperature difference is 4.5 °C;the ground temperature at the depth of the pipeline fluctuates within the range of 27.77±6.4°C,which is 5.54±6.4°C from the control soil temperature.