The Influence Of Wall On The Thermal And Humid Environment Of Sunken Solar Greenhouse

As a typical light-energy utilization facility,the solar greenhouse can provide a more longterm suitable growing environment for crops and plays a significant role in solving the problem of a stable supply of vegetables in winter in northern China and improving the income of farmers.At present,most solar greenhouses in the Shou Guang area are made of rammed earth.but the walls must be built very thick to achieve its heat preservation and storage performance,the large floor space is the drawback of rammed earth.So,finding a new type wall which can not only meet the demand for heat preservation and storage but also reduce the floor area of the solar greenhouse is the focus of our research.In the process of studying the new wall,it is necessary to evaluate the heat preservation and storage effect of the wall,among which the most intuitive way is studying the effect of walls on the hot and humid environment of a solar greenhouse.The thermal and humid environment of a solar greenhouse directly affects the yield of crops,and it is greatly affected by the envelope structure.So it is of considerable significance to study the thermal and humid environment of a solar greenhouse.In this paper,the heat and moisture transfer of soil wall in the sunken solar greenhouse has been studied by theoretical analysis,experimental test,and numerical simulation.This paper proposes a method to transform the wall,and provides reference for the follow-up research.Firstly,the experiment has been designed to collect the data of the thermal and humid environment of the solar greenhouse,acquire the variation rules of the indoor temperature and humidity,wall temperature,and soil temperature and humidity in time and space.The experimental data provide the condition for the study of the heat and moisture transfer in solar greenhouse wall,and provide a reference for the accuracy of study of the heat and moisture transfer in solar greenhouse.Secondly,the heat transfer process of the wall of the solar greenhouse has been analyzed,and the temperature field inside the wall has been studied through numerical simulation.It is confirmed that the wall can be divided into three parts: insulation layer,heat storage layer,and transition layer.This paper puts forward a method to transform the wall from the perspective of heat transfer,and evaluates the heat preservation and storage performance of the wall.Then the wall was regarded as a porous medium to study its mechanism of heat and moisture transfer.The numerical simulation method is used to simulate the heat and moisture transfer of the wall,the comparison between the model and the experimental data shows that the model is dependable and the wall moisture transfer cannot be ignored.Finally,the main factors affecting the thermal and humid environment of the solar greenhouse are studied and analyzed.The thermal and humid environment of the sunken earth wall is simulated by using the two-dimensional unsteady heat and humidity transfer mathematical model of the solar greenhouse.The comparison between the model and the metrical data shows that the model is dependable.On this basis,the thermal and humid environment of the soil wall solar greenhouse after modification is simulated to judge whether the wall reconstruction method is feasible.