Research On The Influence Of Louver External Shading On The Natural Ventilation And Thermal Comfort Of Buildings In Summer

With the warming of the global climate,more and more natural disasters have been caused,and using less fossil energy has become the consensus of all countries.Building is indispensable from energy and consumption is huge.Therefore,the energy conservation of buildings has been paid more and more attention and building shading is one of the important energy-saving measures.At the same time,natural ventilation does not consume non?renewable resources and is also an energy-saving measure.Taking an office building in Nanjing as the research object,this paper first simulates the wind environment of the building with and without louvre shading using CFD method,and obtain the distribution of wind pressure on the outer surface of the building.Then the air distribution of a typical room in the building at 2 PM is simulated.Finally,the thermal comfort of the naturally ventilated room is predicted by using the thermal comfort evaluation model of the natural ventilation applied to summer.The conclusions are drawn from the study of this paper,as following:(1)In the adaptive model,the only influencing factor is the outdoor air temperature,while the environmental factors that have important influence on the body's thermal comfort are not taken into account.Based on the adaptive model proposed by Yang Liu et al.,and considering the effects of air velocity,relative humidity and mean radiation temperature on thermal comfort,the thermal comfort evaluation model of natural ventilation applied to summer was established.(2)The shading louvre outside the building can guide airflow running into the building vertically,reducing the pressure loss of the airflow and increasing the wind pressure on the surface of the building.When the louvre shading facility outside the building is installed for the SSW wall,and the angle of its louvre is 30°,the natural ventilation quantity of the typical room in the building is increased by 9.4%.(3)When the louvre shading facility outside the building is installed for the SSW wall,and the angle of its louvre is 30°,the shading facility reduces the solar radiation heat entering the building through the SSW windows by 64%,and reduces the temperature of the external wall radiated by the sun by 11.7?.(4)When the shading facility outside the building is not installed,the mean temperature is 32.4?,the mean air velocity is 0.27m/s,and the mean air age is 28s in the breathing area of the typical room,and the indoor mean radiation temperature is 34.3?.By using the thermal comfort evaluation model of natural ventilation,the thermal neutral temperature is 26.3?,the upper limit temperature of thermal comfort zone is 28.3?,the room temperature is 4.1? higher than the upper limit temperature of thermal comfort zone,and it is predicted that people will feel very hot in the room.(5)When the louvre shading facility outside the building is installed for the SSW wall,and the angle of its louvre is 30°,the mean temperature is 31.6?,the mean air velocity is 0.29m/s,and the mean air age is 26s in the breathing area of the typical room,and the indoor mean radiation temperature is 32.5?.By using the thermal comfort evaluation model of natural ventilation,the thermal neutral temperature is 27.5?,the upper limit temperature of thermal comfort zone is 29.5?,the room temperature is 2.1? higher than the upper limit temperature of thermal comfort zone,and it is predicted that people will feel hot in the room.When the indoor air velocity is increased to 0.85m/s,the room temperature is in the thermal comfort zone,and the thermal environment of the room at this time meets the requirements of the most people.(6)When the louvre shading facility outside the building is installed for the SSW wall and the NNE wall,and the angle of its louvre is 30°,the mean temperature is 31.5?,the mean air velocity is 0.30m/s,and the mean air age is 26s in the breathing area of the typical room,and the indoor mean radiation temperature is 32.1?.By using the thermal comfort evaluation model of natural ventilation,the thermal neutral temperature is 27.7?,the upper limit temperature of thermal comfort zone is 29.7?,the room temperature is 1.8? higher than the upper limit temperature of thermal comfort zone,and it is predicted that people will feel hot in the room.When the indoor air velocity is increased to 0.80m/s,the room temperature is in the thermal comfort zone,and the thermal environment of the room at this time meets the requirements of the most people.