Numerical Study On The Performance Of Solar Dual-catalytic Trombe Wall Based On Principles Of Photo-/Thermo-catalysis

The SDC-Trombe wall incorporating photocatalytic oxidation technology and thermocatalytic oxidation technology can realize indoor heating and air purification simultaneously,which can effectively reduce building energy consumption and improve indoor air quality,and has great potential for development.Structural parameters have a great influence on the performance of SDC-Trombe wall,but there is a gap in relevant research,which thus becomes the motivation of this thesis.This thesis established and verified the two-dimensional numerical model of SDC-Trombe wall,and the effects of structural parameters(channel height and width,the ratio of height of upper and lower vents to channel widthΔ,modified shape parameter d,fin spacing S and fin height H_fin)and environmental parameters on the performance of SDC-Trombe wall were investigated.In addition,the performance of three air-purified Trombe walls and ordinary Trombe wall under different solar radiation intensities and ambient temperature were compared.The results indicate that channel height can significantly enhance the outlet temperature,ventilation rate and CADR,reduce the air purification efficiency,but influences the degradation rate,thermal efficiency and total efficiency very little.With the increase of channel width orΔ,the ventilation rate,CADR and air purification efficiency show an increasing trend,while the outlet temperature decreases,and the degradation rate increases gradually after falling to the minimum.With the rising of channel width,the thermal efficiency increases at first and then decreases whenΔ<1,but shows a dropping tendency under the condition ofΔ≥1.The total efficiency show a similar tendency with thermal efficiency because the thermal efficiency is dominant when the total efficiency changes.In addition,with the rising ofΔ,both thermal efficiency and total efficiency increase to a maximum and then decrease steadily.The optimalΔcorresponding to the maximum thermal efficiency and total efficiency decreases at first and then remains unchanged at 0.4.Modifications to the shapes of upper and lower vents can effectively enhance the thermal performance,while the air purification performance can be improved slightly only in some cases.The total efficiency and thermal efficiency show a similar changing tendency,and the optimal value of modified shape parameter is 0.05m.The thermal performance and air purification prformance of SDC-Trombe wall can be significantly enhanced by installing the horizongtally distributed fins in the channel,and the appropriate fin spacing and fin height should be determined.As fin height increses,ventilation rate,CADR and air purification efficiency rise to the maximum and then decrease,while the changing tendencies of outlet temperature and degradation rate are opposite to the above parameters.The varying trend of thermal efficiency and total efficiency are similar:when S≤2W,both thermal efficiency and total efficiency are positively correlated with fin height,and rise first and then decrease under the condition of S>2W.Besides,S=W is most conducive to improving the thermal efficiency and total efficiency of SDC-Trombe wall.The higher the solar radiation intensity or the ambient temperature and the lower the ambient wind velocity are,the better the thermal performance of SDC-Trombe wall,while the air purification efficiency decreases with the rising of solar radiation intensity and is little affected by ambient temperature and ambient wind velocity.Comparing the performance of three air-purified Trombe walls and ordinary Trombe wall,it is found that the SDC-Trombe wall shows the best air purification performance at all cases,and its total efficiency are the highest at low solar radiation intensity and ambient temperature.