Research On Collaborative Energy Saving Based On Residential Building Envelope Structure And Indoor Heating System In Cold Area

With the continuous acceleration of urbanization,the carbon emissions of the whole life cycle of China’s construction sector account for more than half of the total carbon emissions of society,and the energy consumption intensity shows a trend of continuous growth.The stock of residential buildings accounts for a relatively large proportion,and energy efficiency retrofit of existing houses will become an important measure to achieve the"dual carbon"goal at an early date.Therefore,how to reasonably and scientifically propose the energy efficiency retrofit strategy of residential buildings has become the focus of this paper,which provides a reference for sustainable development and energy efficiency retrofit.Starting from different energy efficiency retrofit technologies,this paper selects Xi’an,a typical city in cold areas,analyzes its existing residential buildings through questionnaire surveys and field investigations,discusses the most potential links in the energy efficiency retrofit process,and finally uses energy consumption simulation software to scientifically quantify the comprehensive energy efficiency retrofit strategy.The main research contents are as follows:（1）Starting from the energy efficiency retrofit of the envelope structure,four types of single transformation schemes are selected:exterior wall insulation,roof insulation,replacement of exterior windows,and shading technology.The orthogonal combination of four factors and four levels was designed to form 16 alternatives,and the heating and cooling energy consumption of the combined scheme was simulated and calculated by using Design Builder software.Five indicators of energy saving,global cost increment,percentage of uncomfortable time,incremental benefit and cost-effectiveness ratio were selected as the decision-making indicators of scheme optimization,and the index values of alternative schemes were obtained by taking the whole year as the calculation cycle,and the weights of different evaluation indicators were clarified by the entropy weight method and the comprehensive scores were calculated for each scheme,and the weight sizes were 0.138,0.163,0.164,0.237,and 0.298,respectively.（2）For the single-pipe leapfrog system,study the changes of hydraulic conditions before and after the transformation.Calculating the impedance change value before and after the system transformation,it is found that the total impedance S_Bu of the system is 0.15%after the total impedance S_riser of a single riser is connected in parallel,and the impedance change of each riser pipe is not much different.Calculate the relationship between the heat supply of the riser and the change of flow,in order to ensure that the heat supply after the transformation reaches the indoor comfort level,it is necessary to increase the flow rate of the riser pipe to be greater than the flow of the riser before the transformation,and the user with reduced heat dissipation can be solved by increasing the number of radiator pieces.Secondly,the influence of user adjustment on the hydraulic working conditions of the system is analyzed,and when the opening degree of the user thermostatic valve h_i is adjusted consistently,the pressure consumed by the constant pressure differential control valve is reduced after adjustment,and the effect of consistent adjustment on other users is basically the same.（3）Analyze the energy consumption level after the comprehensive energy efficiency retrofit of the envelope structure and heat supply metering.The existing non-energy-saving buildings are transformed according to the 65%energy-saving scenario,and then the heat metering transformation is implemented,and the indoor free heat is effectively utilized,and finally the limit of the building heat consumption index of the 75%energy-saving standard can be met.The main means to achieve a higher energy-saving goal of 75%energy saving for residential buildings is to adopt building heating metering technology,so that its system users have the ability to adjust independently,and the energy-saving benefits are significant.