| Building energy consumption occupies a large proportion in the total energy consumption of the national economy,and external shading has an important impact on building energy consumption.There are various types of external sunshades: sun visors,sun louvers,sun shades,sun shade grills,outdoor canopy curtains and glass coatings.On the basis of drawing on existing technologies at home and abroad,this study is based on the climatic conditions in cold regions,combined with the characteristics of local building structures,and proposes the specific quantitative impact of external shading on building energy consumption in the cold regions of northern my country.It is of great significance to create a comfortable and healthy indoor environment and improve work efficiency.On the basis of expounding the related concepts and mechanism of building external shading,the form and material of external shading,and the relevant factors affecting external shading,according to my country’s building climate division,three typical cities in cold regions are selected: Jinan City,Shandong Province,Hebei Taking Zhangjiakou City,Gansu Province and Lanzhou City,Gansu Province as examples,the basic principles of shading outside the window are discussed.Furthermore,the specific calculation and analysis of solar radiation,hourly solar altitude and azimuth angle are carried out for the typical meteorological data of three typical cities using Design Builder software.Through analysis,it is found that the three regions will reach their monthly total radiation peaks in May or July;among them,direct radiation accounts for more than three-fifths of the total.According to the change of solar radiation with time and latitude and longitude,the shading time of different facing windows in three regions is analyzed and calculated.Then,the specific size of the visor facing each window is calculated by applying the size formula of the sun visor.According to the climate characteristics of Jinan,Zhangjiakou and Lanzhou,the model of the office building was established,and the building parameters and indoor thermal disturbance were set.Subsequently,the energy consumption simulation software De ST was used to simulate the annual energy consumption under the conditions of different shading areas.According to the hourly simulation results,the influence of shading area on building design load,load peak and building energy consumption is analyzed in detail.The research results show that after the use of external shading,the cooling load of the buildings in the three regions is reduced,but the degree of reduction is different;under the condition of full shading in an office building in Jinan,the annual energy saving of the air-conditioning system reaches 246,860 k Wh,which is 25%,50%,75%,100% shading area,energy saving can reach 26.79%,50.74%,77.23% of full shading.In an office building in Lanzhou,the air-conditioning system saves 297,040 k Wh of energy throughout the year under the condition of full shading.When the area of four shades increases,the energy saving of the air-conditioning system can reach 26.78%,53.49% and 80.10%of the total shading.The energy-saving effect of buildings in Jinan and Lanzhou is similar and remarkable,and the maximum energy-saving rate can reach 10.43%.After the addition of shading in Zhangjiakou,the reduction of the peak cooling load is more obvious than that in the other two areas,and shading plays a major role in intercepting solar radiation.In an office building in Zhangjiakou area,the annual energy saving of the air-conditioning system reaches658,270 k Wh when it is fully shaded.When the fourth-grade shade area increases,the energy saving can reach 24.36%,52.61%,and 76.56% of the full shade.reached 5.48%.As the shading area increases,the energy savings of the building’s air conditioning system and the energy efficiency of the building’s energy consumption continue to increase.The regulation of the shading area needs to find a balance between building lighting and reducing energy consumption,so as to realize the integrated design of building energy conservation.After in-depth analysis of the relationship between building energy consumption and external shading in winter and summer in cold regions,it is concluded that in order to reduce building energy consumption,it is necessary to install external shading in office buildings in cold regions,especially movable external shading.This research provides a theoretical basis for the selection and size optimization of external shading of office buildings in cold regions,and has certain reference value for energy saving and carbon emission reduction. |
