Study On High Efficiency Heat Collection Of Sandy Aboveground Pipelines And Seasonal Underground Thermal Storage

With the rapid development of human society,the demand for energy is increasing,and the traditional fossil energy is facing the situation of exhaustion.Therefore,the development of renewable energy has attracted the attention of all countries in the world.As a kind of widely existing renewable clean energy,solar energy has an important ecological and environmental significance for its efficient collection and storage.In view of this,in order to realize the low cost and high efficiency of solar energy heat utilization,this project has carried out a preliminary study on solar energy heat collection and inter-seasonal heat storage.In this paper,the shallow geo-temperature monitoring test and the high-efficiency heat collecting test of the aboveground pipes are designed,the change rules of the shallow geo-temperature and the water temperature in the pipeline are explored.According to the experimental data,the relevant factors affecting the water temperature in the pipe(such as solar radiative intensity,pipes' material,the spatial position of pipe,covering ways of pipe and heat-accumulating wall)were analyzed,and temperature prediction was carried out.The results show that the change trend of soil temperature near the surface(-0.01m)is basically consistent with that of solar radiation intensity on the same day;The water temperature of galvanized steel pipe wrapped with black plastic film is the highest under solar radiation;Moreover,the ANSYS FLUENT software was used to simulate and analyze the spatial distribution law of temperature field of water body inside the pipe and heat-accumulating wall under the action of solar radiation.The simulated results show that the position of the highest water temperature and the water temperature near both sides of the pipe change significantly with the change of solar azimuth and height Angle in one day;In the simulation of covering effect,the average temperature of PE plastic film is higher than the average temperature of heat-collecting wall,and the temperature is relatively higher in the "strip" area where the film intersects with the wall.Secondly,according to the characteristics of rural residential buildings in Turpan area,this paper studies the design and simulation of cross season underground water pool heat storage system.The heat load during the heating period of a single house is calculated by using DeST-H software,and the volume of the pool is determined accordingly.The geometric dimensions of the pool,insulated material and thickness,burial depth,inlet and outlet position of the pipeline and flow rate are designed.In order to verify the rationality and feasibility of the design of the underground heat storage pool,this paper also simulates the three stages of the underground heat storage pool system: heat storage,downtime and heat extraction.The results show that during the heating period,the temperature of the water in the pool drops rapidly,which has dropped to 34.0 °C by the end of the third month,and direct heating can no longer meet the need for heating.Therefore,in the following heating period,the water source heat pump can be used for indirect heating.