Existing Buildings And Near-zero Energy Buildings Comparative Study On Energy Consumption And Economy

How to deal with global warming,reduce carbon emissions,and achieve sustainable economic and environmental development has become a challenge facing the world.Buildings are developing in the direction of continuously improving quality,reducing energy demand,increasing energy efficiency,and using renewable energy."Near zero energy buildings"with low energy consumption,low carbon emissions,and high comfort have gradually become a new trend in the development of building energy conservation.Based on the"Design Standards for Energy Efficiency of Public Buildings"GB50189-2015 and"Technical Standards for Near-Zero Energy Buildings"GB/T51350-2019,this paper analyzes the building load characteristics of existing buildings,buildings with energy efficiency of 65%,and buildings with near zero energy consumption,Energy system operating characteristics,full life cycle economy and carbon emissions to study the energy-saving and emission-reduction effects of buildings under different energy-saving standards.First,the heating system of a university complex was tested for 54 days.The measured and calculated data during the test period provided data verification support for the subsequent model establishment.The main measured data are indoor and outdoor temperature,the temperature of the supply and return water of the heating pipeline,the flow rate,and the heating heat is calculated.Through the analysis of the data,the results show that the average indoor temperature of the building is 20℃,which meets the requirements of human comfort.The heat consumption index of the heating season is 53.95W/m~2,which meets the energy consumption index at the time,but there is a big gap between the energy consumption index of nearly zero-energy buildings.Secondly,the De ST energy consumption model is established on the basis of the existing building profile.The measured data and simulated data of the test period are selected to verify the accuracy of the simulation,and then 65%energy-saving buildings and nearby buildings are established in accordance with the requirements of different energy-saving standards.Zero energy building model.Existing buildings and building energy systems with 65%energy saving are built by De ST software to establish a boiler heating/water cooling unit system.The near-zero energy building energy system uses TRNSYS software to establish a solar ground source heat pump system,and explores the operating characteristics of series and parallel solar ground source heat pump systems,and selects the optimal operating mode.The results show that the operating energy consumption of 65%energy-saving buildings and nearly zero-energy buildings have been reduced by 22.31%and 60.05%respectively compared with existing buildings.Finally,combined with the load characteristics of the building and the energy consumption of the energy system,the differences in the economy and carbon emissions of the three types of buildings in the whole life cycle are analyzed.The results show that the total life-cycle cost of 65%energy-saving buildings and near-zero energy buildings are reduced by 25.6%and 36.07%compared with existing buildings,and the life-cycle carbon emissions have been reduced by 24.93%and 45%respectively.A comparative analysis of the energy-saving and emission-reduction effects of buildings under different energy-saving standards provides a reference for the study of national near-zero energy buildings.