Analysis Of The Impact Of Tree Planting Outside The Buildings In Chongqing On The Energy Consumption Of Building Air Conditioning

Due to the rapid development of urban construction and the ever-increasing improvement of people's living standards,building energy consumption is continuously rising.Therefore,it is urgent to find energy-saving technologies that are suitable for sustainable development to achieve building energy conservation.The application of greening in the reduction of building energy consumption has achieved many results.For example,greening methods such as vertical greening of external walls and greening of roofs can significantly reduce the energy consumption of air conditioning in rooms.However,the study about of planting green trees outside buildings on the energy consumption of building air conditioners is rare.This article mainly through the experimental study of buildings in Chongqing area,compared and tested whether there are differences in outdoor air temperature,solar radiation intensity and air-conditioning energy consumption of two air-conditioned rooms under the effect of external tree planting greening.The impact of air conditioning energy consumption was analyzed and its energy saving effect was analyzed.Finally,the energy simulation software DeST was used to analyze the relationship between outdoor air temperature,indoor radiation heat gain and energy consumption of building air conditioners.At the same time,the cooling effect of specific green tree species was summarized and obtained.The main results are as follows:After testing,due to the transpiration and sunshade effects of plants,planting trees outside the building have a very good cooling effect:under the experimental conditions,the average outdoor air temperature under the effect of shading without external planting trees in summer is more than the outdoor average under the shading effect of external planting trees.The air temperature is 4.1°C.The average outdoor air temperature under the sunshade effect of no planting in winter is 1.8°C higher than the average outdoor air temperature under the sunshade effect of the planting tree.At the same time,planting trees outside the building can effectively reduce the amount of solar radiation from outside the building to the outside:under experimental conditions,the average solar radiation intensity of the shade-free field during the summer is 421.6 W/m~2;The average solar radiation intensity under the shade of the action is 53.4 W/m~2,which is only 1/8 of the protection of the shade without external planting trees.The average value of outdoor solar radiation under the sun-shading effect of no planting trees in winter is 79.7 W/m~2.Due to the fact that the outdoor greening tree species do not fall off in winter test conditions,the shade shades the solar radiation,making it possible to shade under the effect of external planting trees.Outdoor solar radiation is almost zero.For this reason,choosing solar shades to reduce solar radiation in summer and adding solar radiation to trees in winter can be a way to reduce the annual air-conditioning energy consumption.Because the trees outside the building will have a positive impact on the air temperature and humidity around the building,through theoretical calculations,the average annual electricity consumption of room air conditioners under the influence of planting trees outside the building is 7.44 kWh lower than that of room air conditioners without the effect of planting trees outside the building.Reasonable tree planting outside the building will help reduce the energy consumption required for air-conditioning to handle fresh air,and contribute to air-conditioning energy conservation.In addition,using representative typical meteorological year data from Chongqing in the DeST software,the building energy consumption simulation results show that under summer conditions,the outdoor air temperature is increased by 1°C,and the air-conditioning seasonal cooling load index is increased by 5.55W/m~2.Under winter conditions,the heat load index of heating season is reduced by 5.36 W/m~2 for every 1°C increase in outdoor temperature.At the same time,the annual energy saving of room air conditioning caused by planting tree outside the building can be calculated as 60.98 KWh,and the reduction of carbon dioxide emissions through energy conservation is 14.33 Kg.In the promotion to the whole Chongqing area,the energy saving and emission reduction amount obtained by planting green trees outside the buildings is significant,and the energy saving effect is obvious.Finally,according to comprehensive analysis of various data,the recommended native tree species suitable for greening outside the Chongqing area are:Lotus Magnolia,Osmanthus fragrans,Machilus nanmu,Robinia pseudoacacia,Cinnamomum camphora,Bischofia javanica,Ligustrum lucidum,Ficus microcarpa,Ficus virens,Syzygium jambos.These tree species can not only adapt well to the climatic conditions and natural geographical environment in Chongqing,they have good economic effects for planting,and they have a strong shading effect in the summer and a large cooling rate,which can effectively reduce the air conditioning load in summer,reduce air conditioning energy consumption,and save energy.The effect is good.Among them,Robinia pseudoacacia,Liquidambar formosana,and Ficus microcarpa are deciduous trees.Winter deciduous trees can effectively increase solar radiant heat in the room,reduce heat load on heating,and achieve a more comprehensive energy saving effect throughout the year.It is more suitable for use in Chongqing's environmental greening planting tree species.