Numerical Investigation On Ventilation Characteristics And Optimization Of Combined Solar Chimney

With the progress of society and the improvement of people’s living standard,the energy crisis and environmental pollution is more and more serious, andthe proportion of building energy consumption in total energy consumption ismore and more bigger, which have accounted for more than30%of the totalenergy consumption in our country. The energy efficiency of the buildingindustry have become a hot topic of the construction industry energyconservation with energy consumption and environmental problems. Solarchimney is through the use of solar energy and wind energy to ventilating,removing wasted heat and wet, which is an effective measures of improvingthe indoor air quality. In the actual application of solar energy chimney will beaffected by the outdoor wind speed and wind direction, the coupling effect ofwind pressure and hot pressure on the solar chimney ventilation performancehas important role.In this paper, the different structural parameters (solar chimney slopelength and width) and outdoor parameters (outdoor wind speed and heat flux) of combined solar chimney under the coupled of wind pressure and heatpressure to make numerical simulation study; With shutter is proposed on thebasis of the structure of the combined solar energy chimney, and itsperformance are studied.The main research contents and results are as follows:(1) Established the mathematical and physical model under the action ofwind pressure and heat pressure of solar chimney; Consider its outdoor windfield calculation area is determined; The generation of complex computinggrid and proceeding grid independence assessment; Numerical simulationcompared with the experimental data, verified the reliability of themathematical model and physical model of the combined solar chimney.(2) The flow rate of the coupled of wind pressure and heat pressure ofcombined solar chimney is increasing with the increase of the chimney widthby the numerical simulation analysis, but the increasing scope is decreased; theflow rate increased with the increase of slope length of the chimney.(3) The velocity of inlet section increased with the increase of the widthand slope length of the chimney, but the wind speed of inlet section at the inletheight direction decreased with the increase of chimney width; At the sametime, velocity and temperature of outlet section of the chimney increased whenthe width and slope length of chimney increased.(4) The flow rate and outlet velocity of combined solar chimney alongwith the increase of outdoor wind speed and heat flux increased gradually when changing the parameters of outdoor; The pressure difference andtemperature difference between inlet and outlet of the chimney increased withthe increase of heat flux.(5) Optimized structure of the combined solar energy chimney and withshutters of combined solar chimney is put forward，which installs shutters andflapper in the glass. The optimized structure could make an effective on usethe outdoor wind, induce the air of chimney flowing and increasing air speed.So that can make the flow performance enhanced.(6) Under the same conditions, the temperature field and flow fieldinside the chimney channel is better than the original structure of the chimneyfor the optimized structure of the combined of solar energy chimney. Under thesame conditions, wind speed of optimized structure of the solar chimney wasobviously higher than the original structure. Such as at the same solar radiation,even if the original structure chimney on the environment of the biggeroutdoor wind speed, the optimized structure chimney on the environment ofthe smaller outdoor wind speed, the speed of optimized solar chimney will besignificantly higher than the original structure. Outdoor wind pressure couldmake effect on ventilation rate of the chimney and add the flow rate ofoptimized structure.(7) When the shutters angle increased, outdoor wind can induce airflowing out and enhance the flow rates in a certain angle of the shutters andunder the action of flapper of the optimized chimney; The outlet temperature of chimney increases with the increase of heat flux of optimized chimney; Andthe outlet temperature decreased with the increases of outdoor wind speed ofoptimized chimney.