GA-based Study On Optimization For Energy-saving Of Facade Openings Design Of High-rise Office Building Standard Floor

Energy shortage is a common global problem,energy conservation and emission reduction are urgent.Building,as the basic place of human activities,consumes plenty of energy and resources.With the economic development and people’s living improvement,building energy consumption will remain increasing.The total energy consumption of China’s construction operation accounts for 1/3 of that of the whole country.Plus other phases of the building life cycle,half of society’s energy consumption comes from buildings^[1].High energy-consuming buildings not only bring a heavy energy burden to society,but also greatly restrict the pace of sustainable development in China.Since 1980s,China has put forward the requirement of building energy efficiency,and has experienced the energy-saving 30%in“Energy conservation design standard for new heating residential buildings”（JGJ26-86）,50%in“Energy conservation design standard for new heating residential buildings”（JGJ26-95）,and 65%in“Design standards for energy efficiency of public buildings”after 2005.At present,some regions have entered the fourth stage,taking the lead in formulating new standards for energy efficiency 75%.In recent years,with the acceleration of urbanization,building energy consumption is on the rise,new buildings and building renovation are consuming lots of energy.Compared with other types of buildings,office buildings have a high proportion in this aspect due to the long retention time of people’s activities such as working and the increasing equipment usage.Simultaneously,unscientific design also increases their energy consumption.The above reasons lead to high energy consumption of public buildings become a prominent problem,especially in cold regions.According to statistics,Heating alone exceeds the national average level by 27%in cold regions,accounting for 30%～40%of the total regional energy consumption.73%～77%of building energy consumption is lost through enclosure system,and the energy loss of external windows accounts for more than 50%of the external enclosure structure^[2].It can be seen that in order to reduce building energy consumption,the design of building facade opening is the key to energy saving.For high-rise buildings,the standard floor occupies a larger design area and use space,and its energy consumption plays a decisive role in the whole building.Therefore,this paper selects Yantai as a typical city in cold regions.We find and summarize the design strategies and laws of the energy consumption reduction of the facade openings of high-rise office buildings in the cold region by studying the correlation between facade openings and building energy consumption,providing first-hand reference for experts,scholars and professionals.In this paper,Pareto or Pareto front is searched globally with the help of Ladybug+Honeybee in Grasshopper,combined with genetic algorithm（GA）.Referring to“Design standards for energy efficiency of public buildings”（GB 50189-2015）and“Design standard for energy efficiency of residential buildings in severe cold and cold zones”（JGJ26-2018）,abstract model of high-rise office building standard floor in Yantai is established.The influence of opening orientation,size,height and other factors on building energy consumption is studied through the geometric and rasterization methods of facade openings.Firstly,opening factors are designed as evaluation genes,such as window-wall ratio（WWR）,window height（WH）,and sill height（SH）.The correlation between opening factors and annual energy consumption of air conditioning cooling（AC）,heating（AH）,lighting（AL）,and the totaling（AT）of three objects above is studied.Secondly,based on single-objective GA and multi-objective GA,minimum of AC,AH,AL and AT,opening forms are obtained respectively,and the causes are analyzed.Finally,the practicability and effectiveness of two energy saving strategies above are verified by examples.In the light of research results,this paper hopes to provide architects some reference and inspiration for energy-saving design in Yantai and other cities in cold regions.