| Under the increasingly severe global climate,China has made a commitment to peak and neutralize carbon emissions by 2030 and 2060 separately.As an industry with high energy consumptions and emissions,the energy renovation of the existing building has become an important and necessary path to achieve the‘dual-carbon’and sustainable development goals.However,the decision-making of building renovation in China mainly depends on‘empirical’and‘scenario analysis’methods.Few studies have been carried out to investigate the decision-making using digital tools and methods.The above gaps form the limitation of Chinese government to accurately plan and control energy consumptions and carbon emissions in existing buildings.Based on existing achievements,this study constructed a standard building model that can represent the characteristics of the building type and climate in hot summer and cold winter regions.Furthermore,a comprehensive list of renovation strategies of existing buildings has been constructed through the literature review and expert interviews.Then,proposed a decision-making model to reach the minimum energy consumptions,renovation costs and discomfort time of existing buildings.The renovation strategies about exterior walls,roofs,exterior windows and HVACs were considered in this decision-making model.Finally,the decision-making between renovation strategy and demolition and reconstruction strategy were carried out.The key contributions of this thesis are listed below:(1)This study constructed a standard building model and formulated a list of energy renovation strategies.This study is the first to systematically analyze and summarize the development trends of civil building area and energy consumption,then investigated the temperature,precipitation,relative humidity and other meteorological parameters of eight representative cities in hot summer and cold winter regions.Based on this,this paper constructed a standard building model by a survey.Secondly,through literature review,renovation strategies have been analyzed which involved topics such as envelope,HVACs,lighting and power supply and distribution system,water supply and drainage system,etc.Finally,a panoramic list of renovation strategies for existing buildings were determined by expert interviews and questionnaire surveys.(2)This study carried out the decision-making on strategies of building comprehensive renovation.Based on sustainable development theory,this study selected the building energy consumption,renovation cost and percentage of discomfort time as the decision objectives.And determined the types and thickness of insulation materials in exterior wall and roof,the types of exterior window and the window-to-wall ratio as the main decision variables,the types of HVACs in Energyplus as the supplementary decision variables.Then a decision-making model was constructed based on NSGA-III,which can conduct real-time energy simulation for a building.Finally,the decision-making model has been carried out for the standard building model.The results showed that:1)The objectives have been gradually optimized as the number of iterations increases.There is negative correlation between building energy consumption and renovation cost.The relationship between the percentage of discomfort time and renovation cost is also negative.However,there is a positive correlation between the percentage of discomfort time and energy consumption.All above conclusion is consistent with the actual situation,which confirms the rationality and applicability of the model.2)The value of energy consumption before optimization is 150.396)(2?/8)~2,and the highest value is 143.436)(2?/8)~2 after optimization,the value can be reduced by 6.966)(2?/8)~2 and 22536.48k Wh every year,which shows the significant effect of energy renovation.3)The value of energy consumption reduced from 143.436)(2?/8)~2 to 77.826)(2?/8)~2,and the value of the percentage of discomfort time reduced from 38%to 27%,which reflecting the necessity and effect of multi-objective optimization.(3)This study carried out the decision-making between comprehensive renovation and demolition and reconstruction.This study explored the possibility and rationality of the integration of life cycle emergy analysis and co-benefit theory at first.And constructed the decision-making model for comprehensive renovation and demolition and reconstruction.Then,under the precondition of meeting mandatory standards and specifications,this paper constructed the demolition and reconstruction strategy based on comprehensive renovation strategy generated by the multi-objective optimization.Afterwards,a more sustainable strategy can be selected by carrying out the co-benefits analysis between renovation strategy and demolition and reconstruction strategy.Finally,conducting the co-benefits analysis for the standard building and the results showed that:1)The value of total emergy inputting in the whole life cycle of the comprehensive renovation strategy and the demolition and reconstruction strategy are the 1.27E+21 sej,1.32E+21 sej respectively,which shows that the resources and energy consumed for comprehensive renovation strategy is lower than the demolition and reconstruction strategy.2)In research periods,the emissions of building waste for comprehensive renovation strategy is higher than demolition and reconstruction strategy,indicating the long-term advantage of the demolition and reconstruction strategy.3)The co-benefits of the emergy sustainability indicators of the comprehensive renovation strategy and the demolition and reconstruction strategy are 0.00037 and 0.00028,respectively,reflecting that from the perspective of sustainability,the comprehensive renovation strategy is better than the demolition and reconstruction strategy.The above efforts offer a scientific and systematic decision tools for decision making of energy saving and emission reduction of existing buildings,and provide a necessary and reference significance for accelerating the realization of the‘dual carbon’goal and sustainable development goals. |
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