Analysis And Application Research On The Impact Of Greenery Enclosure Structure On Energy Consumption Of Building Projects

Greenery enclosures can effectively limit the heat gain of building facades and have become one of the most effective ways to save energy in buildings.In addition,increased greening can improve roof rainwater management and indoor thermal comfort,so more and more buildings have adopted roof greening or vertical greening.However,there are also problems in the practical application of the greening of facades,such as maintenance costs and different growth characteristics of the plants themselves.This study selects ten common plants that can be used in green buildings as research objects and analyzes the heat transfer characteristics of various green plants,as well as the energy-saving and economic benefits of these plants in actual cases of being used in outdoor greening.Firstly,this study experimentally measured the thermal conductivity of ten different types of green plants and deduced the thermal resistance of the leaves of different types of plants.Thermal resistance ranges from 0.001 to 0.005m2 K/W.Then,the functional relationship between the thermal conductivity and the water content of the blade is fitted,which provides a method for the subsequent study of thermal conductivity acquisition.Secondly,this study used wind tunnel experiments to determine the relative humidity of ten different types of plant leaves,the intensity of convective heat transfer between each type of plant leaf and the surrounding air under natural conditions,and the effect on the surrounding air humidity.The relative humidity increased between 2%and 10%before and after the air came into contact with the plant leaves,according to the results of the experiment.Between each kind of blade and the air,the convective heat transfer coefficient is between 2 and 6 W/（m2·K）.The experimental findings are remarkably similar to those obtained from related theoretical calculations.This study fitted the correlation between the leaf area index LAI and the convective heat transfer thermal resistance of the vegetation layer to make the subsequent acquisition of the convective heat transfer thermal resistance of the vegetation layer easier.Thirdly,further theoretical research on the thermal resistance of vegetation layer in green enclosure structure is carried out to obtain the equation for calculating the thermal resistance of vegetation layer.The thermal resistance,thermal storage coefficient,attenuation multiplier and delay time of vegetation layer in green building are calculated by the results measured in the above experiments.After comparing the calculation results,we found that the thermal attenuation multiplier increased from 114.6 to 157.7 for the wall and from 36.3 to 52.1 for the roof,an increase of 37.6%;the delay time increased from 7.54 h to 9.41 h for the wall,an increase of 24.8%,and from 5.28 h to 6.82 h for the roof,an increase of 29.8%.The above data have laid the foundation for the analysis of building energy consumption in the subsequent analysis of actual engineering cases.Finally,this research has conducted an economic and energy consumption analysis of a five-story building in Zhengzhou.Calculating the summer cooling load and winter heating load before and after using the greening of the facade was used to conduct an energy analysis.The paper also calculates the full life-cycle cost and static and dynamic payback period of the building’s use of facade greening to evaluate its economic benefits.The annual electricity savings are estimated to be around 4134 kWh.The building’s static investment payback period is 19.5 years and the dynamic investment payback period is 21.5 years after adding the greening of the facade.