Study On Heat Transfer Performance Of Closed Cycle Solar Wall

This paper takes the solar wall laboratory located in Dalian civil engineering research and development center of Liaoning province as the research object,and builds the solar wall experiment system with automatic control independently.Dalian city of Liaoning province is located in the northeast of China,which is an area with abundant solar energy resources.The building climate is a cold region,and the heating in winter is mainly coal,which leads to serious environmental pollution.Therefore,the use of solar energy for heating can meet the needs of winter heating and reduce ecological damage and environmental pollution.This paper mainly carries out a dual study of simulation and experiment.First,it carries out real-time monitoring of the whole heating season(173 days)through the experiment,and obtains the influence range of the closed solar wall system with external cavity circulation through data analysis of radiation,wind speed and outdoor environment.Then,through numerical simulation,the size of the suitable closed solar wall system with external cavity circulation is determined and the fan's starting time is determined.Finally,according to the conclusion of simulation and experiment,the operation of the closed solar wall system with external cavity circulation in cold areas is summarized.The main research results are as follows:(1)The sunny weather Dalian solar total radiation intensity is higher,by seepage,heat conduction,convection and radiation heat transfer forms such as can make the collection hot plate and the cavity temperature increase,the efficiency of the solar wall at 53.16%,higher than a conventional solar wall efficiency,experiments with external cavity closed circulation solar panels wall system covers an area of 12.6 m~2,and the experiment room area is 36.4 m~2,therefore,in the Dalian area 1 m~2solar wall system can supply the required heating room 3 m~2.(2)Through simulation calculation,the closed-loop solar wall system of outer cavity can effectively provide the required heat for the required heating room from 10:00 to 16:00 during the heating season in Dalian,while other auxiliary energy needs to be used during 8:00 to10:00.The solar wall system size suitable for Dalian is 3m.The outer cavity range is 0.09m~0.11m,and the inner cavity range is 0.14m~0.16m.The best time for the fan to start is 9:30minutes,and the fan is shut down after 16:00.At this time,although the solar wall system cannot supply hot air for the room,the air left in the cavity can keep the indoor temperature for about an hour.(3)Through continuous automatic monitoring of the temperature of the closed solar wall system with external cavity circulation,it can be concluded that in the case of large outdoor wind force,although it will not have a greater impact on the solar wall system,it will lead to a decrease in the heat supplied to the room by 4.8?;Similarly,when the outdoor temperature is low,the heat provided to the room by the solar wall system will be reduced.In this case,the room temperature will be 1.4?lower than normal.And for rain and snow days,cloudy days,haze days and other bad weather,because the radiation intensity is insufficient,so that the heating effect will be reduced,auxiliary energy needs to work more.