Impacts Of Climate Change And Building Energy Conservation Measures On City-scale Buildings Energy Consumption

"China Building Energy and Carbon Emission Research Report 2021"pointed out that the total energy of the whole building process in China was 2.233 billion tons of standard coal in 2019,accounting for 45.9%of the total energy in China.In order to achieve the goal of carbon neutrality,it is necessary to carry out energy-saving and emission-reduction work in the building sector.In the context of global warming,how to achieve the goal of low emissions for buildings is the focus of current building energy-saving work.This paper takes city-scale buildings in Changsha as the research object,considers the future climate change and the application of building energy conservation measures,analyzes the impact of the two factors on the energy consumption of city-scale buildings in Changsha,and explores the energy conservation potential of city-scale buildings.First,getting the weather data of Changsha in 2050s and 2080s in the future.In this paper,the linear fitting method was used to analyze the changing trend of the annual average temperature in Changsha in the past 40 years.The results show that the annual average temperature in the past 40 years has shown a fluctuating upward trend with the passage of time.And the future weather generator Weather Morph was used to predict the weather files in 2050s and 2080s under the future low-emission scenario of Changsha.The results show that the annual average temperature of the base year is 18.05℃,and the annual average temperature in 2050s and 2080s will increase by 1.72°C and 2.48°C.Second,Open Studio-Standards was used to build benchmark model of large office building.Open Studio-Standards is an open source code library developed by the National Renewable Energy Laboratory of the United States,which can quickly generate building energy models that meet the corresponding building energy-saving standards.This paper referred to energy-saving standards such as"Design Standard for Energy Efficiency of Public Buildings in Hunan Provincial"and related literatures,and it redefined the benchmark parameters of large office building in Open Studio-Standards to generate benchmark model,and inputted the base year,2050s and 2080s weather files,then it obtained the annual energy simulation results of the three years.The simulation results show that the total source energy of the benchmark model in the base year was 365.93 k Wh/m~2,372.99 k Wh/m~2and 374.89k Wh/m~2in 2050s and 2080s,with an increase of 1.93%and 2.44%respectively.Further,the building energy simulation software EnergyPlus was used to establish the energy-saving model of large office building.On the basis of benchmark model of large office building,this paper referred to energy-saving standards such as"Technical Standard for Nearly Zero Energy Buildings",energy retrofit analysis toolkit CBES and related literatures,then this paper used EnergyPlus to add four building energy conservation measures and applied renewable energy to establish energy-saving large office building model.The simulation results show that:(1)In the base year,the total source energy of the building models applying"envelope performance optimization","lighting system optimization","HVAC system optimization"and"equipment system optimization"was 361.04 k Wh/m~2,329.10 k Wh/m~2,306.97 k Wh/m~2and 301.90 k Wh/m~2respectively,and the energy-saving rate was 1.34%,10.08%,16.11%and 17.50%respectively,of which the model applying"equipment system optimization"had the highest energy saving rate.The total photovoltaic power generation per unit roof area of the building model of"installing roof solar photovoltaic system"in the base year was 63.20 k Wh/m~2and it was used to replace building electricity,which was equivalent to source energy-saving rate of 4.50%.(2)And if four building energy conservation measures were added and renewable energy was applied at the same time,the total source energy in energy-saving model would be 211.61 k Wh/m~2,and the energy-saving rate could reach 46.67%when considering photovoltaic power generation.Finally,this paper expanded the research objects,and a total of 59,332 buildings of 22building types in Changsha were studied,which covered a total construction area of 35.39million m~2.We developed the climate＿scenarios module in Open Studio-Standards,and defined benchmark parameters and energy-saving parameters in Open Studio-Standards according to the settings methods in the previous two chapters,and generated baseline models and energy-saving models of 22 kinds of buildings.The simulation results show that:(1)For the impact of climate change,the baseline model of city-scale buildings had a total source energy of 7113.02 GWh in the base year,7327.94 GWh and 7424.17 GWh in 2050s and2080s,with an increase of 3.02%and 4.37%respectively.(2)For the impact of building energy conservation measures,taking the base year as an example,when the four kinds of building energy conservation measures are applied,the total source energy of 59332 buildings in the base year was 3870.87 GWh,and the energy-saving rate was 45.58%.