Study On The Effect Of Duct Wall Ventilation Solar Greenhouse Heat Storage

To improve thermal performance of solar greenhouse back wall,the wall structure of the traditional greenhouse wall after wall ventilation passive heat storage performance test.The vertical ventilation test and horizontal ventilation test are carried out respectively.(1)The vertical wall masonry after ventilation and thermal performance test have been tested.The test results show that greenhouse tests and control greenhouse temperature heating rate were 2.58,3.70? /h under the weather conditions,which means the transformation of the greenhouse after wall has better heat absorption capacity than that is not transformed.So the indoor temperature and heating rate are reduced.The temperature difference at 2 seat indoor temperature is very small,because the heat capacity of the walls after midnight greenhouse after the transformation is strong,so that the indoor temperature increased by 1.03 ?.From the experiment of greenhouse wall surface 5 and 10,15 cm,the maximum temperature difference was 4.08,4.73,5.86?.In the day storage stage,the deeper the wall is,the lower the temperature,which shows that wall is in heat storage;in the night exothermic stage,the deeper the wall is,the higher the temperature,which shows that wall is in heat release.No matter the whether is sunny or cloudy,layer thickness around the duct whose temperature is determined by the wave heat storage are more than 50 cm.Cloudy conditions has similar results with the typical weather.And the yield and quality of Tomato in greenhouse was increased than the compared ones.(2)In order to improve the storage performance of wall soil air heat exchange system,we built with a single heat storage function of wall in solar greenhouse,wall mounted inside the earth to air heat exchange system,the system uses the permeability pipe and non permeable pipe combination of ventilation pipe,pipe is horizontally "bow" Shaped layout.This paper carried out the experiments in different wind speed,air temperature,soil temperature under heat storage effect.The test results show that: the storing and releasing heat of the wall air and soil heat exchange system has a relationship with wind speed,air temperature and soil temperature.In sunny day of winter,under the condition of the same air temperature,soil temperature,as the wind speed increases,the heat release system increases;when the inlet velocity is less than 2 m/s,the system storage capacity increased as wind speed increases,when the inlet velocity is greater than 2 m/s,the heat storage system had little difference;in the same wind velocity,with the difference of indoor air temperature and soil temperature increases,temperature difference of air inlet and outlet increasing,increasing heat storage.Air inlet in sunny day with a wind speed of 0.5,1,2,4 m/s operation,exothermic stage,air inlet and outlet average temperature difference were 5,6.6,5.6,4.2 ?,the average heat flow rate were 9.8,32.5,57.4,73.9 W;in the heat storage stage,air inlet and outlet average temperature difference were 10.8,6.4,6.8.4.1 ?,the average heat flow.21.4,31.5,70.2,72.9 W.When the air inlet of horizontal ventilation and heat storage system is operated at the speed of 0.5 ~ 4 m/s,the average temperature of the soil is higher by 1.7~1.9 ? than that without heat exchange system.