Study On The Thermal Performance Of Solar Thermal Storage Walls In Winter And Summer Conditions

The haze in China makes people realize the seriousness of the pollution.With the development of the project of changing fuel from coal to natural gas in heating and industry,burning coal in the countryside becomes the main source of haze pollution.Therefore,how to use clean energy properly in rural areas becomes the main problem to defeat the haze.Scattered coal is mainly burned during the winter heating period.To explore alternative to small boiler heating method is practically significant.In recent years,the technologies of solar-thermal conversion and PCM using in the building provide technical soil for the research of new heating mode.Based on the two technologies,this paper puts forward the solar thermal storage walls of new type of heating mode.Both consider the transformation between winter heating and summer cooling,the feasibility of this approach is studied in order to solve the haze pollution.This article starts from the flow rules of hot water in the vacuum tube,the mathematical mode are established on the basis of the principle of fluid mechanics,the flow law of the hot water is studied under the different inlet temperature,different diameter,and different flow,which provided a theoretical basis for the vacuum tube Scale used in heating.Heat storage material uses the the decanoic acid and the lauric acid,Considering that it can be used both in winter and summer,26 ? as the phase temperature of heat storage material is suitable.The Coefficient of thermal conductivity of the mixture added expanded graphite is tested.In oder to study its actual effect,the thermal storage wall is build with five thermal storage plates.And there is a gap between the thermal storage plates,Besides,coil is lay inside heat storage plate.This paper studies on the surface of the wall temperature and thermal storage plate of internal heat storage material melt,heat flux,indoor temperature distribution,temperature distribution,and the relationship among temperature distribution and heat transfer and the external air inlets in the typical days in winter and summer.Seen from the results,the basic control indoor temperature is between 16 and 20?,the thermal storage wall can well meet the requirements of the heat indoors.It has reached the requirement of cooling in summer with controling the indoor temperature in 27? or so.In the summer night cooling mode,the internal heat accumulated in the thermal storage wall can discharge timely.According to the size of the test bench the mathematical physical model is been established.Simulation is carried on the air distribution and the internal temperature distribution.the results are good;at the same time the air flow short circuit problem is found.By establishing a mathematical model of dynamic response,we simulates the changing indoor temperature over time.The experimental results are basically identical with the simulation results.In the part of the system optimization,we study the distribution of tuyere Angle,furthermore,propose the improvement direction from the respect of the regional weather,the heating area,collector connection mode,and the performance of phase change materials.