Study On Influence Of Vertical Greening On Building Microclimate And Energy Consumption

The layout of city blocks is changing dramatically,causing climate change in some of its regions,thereby exacerbating the urban heat island effect.In the context of global energy conservation,emission reduction and environmental friendliness,various countries are paying more and more attention to the microclimate and energy consumption of buildings.The energy consumption of air conditioners in buildings is closely related to the microclimate.By improving the outdoor microclimate to reduce the energy consumption of air conditioners,and then by reducing the energy consumption of air conditioners to improve the outdoor microenvironment,such a virtuous circle has become the goal that people pursue.At this time,the emergence of vertical greening wall has attracted wide attention,vertical greening wall has been a relatively mature technical means,it not only plays a positive role in building energy conservation,but also one of the important strategies to alleviate the urban heat island effect.It is one of the most common means to explore the practical benefits of vertical greening.Yet at present,a single simulation software cannot solve the above-mentioned problems at the same time.The common research method is the one-way coupling of dual software,but the research content cannot meet the comprehensive requirements.On this basis,this paper proposes to use ENVI-met,Energy Plus,Fluent software to achieve a two-way coupling exploration of the surrounding microclimate and air conditioning energy consumption,to further analyze the comprehensive role of the vertical greening system in the dynamic heat transfer process.First,use ENVI-met software to simulate the microclimate around buildings in a typical block,analyze the characteristics of the actual microclimate in the urban block,compare the difference with the original meteorological data,and analyze the direct impact of vertical greening on the microclimate.Then,the external temperature and humidity of the building and the wall surface temperature simulated by ENVI-met,which are closer to the actual situation,are used as the boundary conditions of Energy Plus to calculate the energy consumption of building air-conditioning to analyze the quantitative evaluation and prediction of the energy-saving effect of vertical greening on air-conditioning.Finally,the heat transfer of the fluid is simulated by Fluent,and the energy consumption of the air conditioner simulated by Energy Plus is discharged into the microenvironment simulated by ENVI-met in the form of sensible heat through the wind speed inlet,to get the comprehensive impact evaluation of vertical greening system on the external microclimate of the building.Using the research method of multi-software and multi-objective coupling,the microenvironment of the five block layouts set is studied.The results show that: 1)The actual microclimate parameters in the block and the parameters provided by the meteorological files are inconsistent in thermal characteristics.The difference is because the layout of urban buildings interferes with shading and wind fields,while the concrete and asphalt surfaces exacerbate the heat island effect during the day.2)Different outdoor microclimates have an impact on the cooling and heating loads of building air conditioners.In summer,the use of vertical greening has the effect of heat insulation and humidification,so that the five types of buildings can reduce the energy consumption of air conditioners by 11% to 15%.3)Comparing with and without building condensation heat exhaust conditions,vertical greening increases the magnitude of changes in microclimate parameters.Vertical greening can reduce the average temperature around the building,and the maximum hourly temperature is between0.4 and 1.0 °C,reducing the average heat island intensity by 0.14 to 0.43 °C.It can be seen that the vertical greening system not only affects the energy consumption of the building,but also affects the condensing and exhaust heat of the air conditioner,which further affects the external microclimate of the building.To sum up,in order to make the research content closer to the actual situation of the built environment,it is very necessary to adopt the research method of multi-software and multi-objective coupling,which can realize a more comprehensive evaluation of various scenarios.The research methods and conclusions of this paper will provide guidance for urban planning and the formulation of related norms.Decision makers can make more suitable recommendations and regulations according to different scenarios in combination with complex actual situations.