Research On The Quantitative Analysis Of Building Carbon Emissions And Assessment Methods For Low-carbon Buildings And Structures

Recently,the issue of carbon emission has drawn worldwide attentions,with insightful understanding of the serious consequences by global climate change.As a developing country with a large population,China contributes nearly half to the world's total amount of newly-built buildings,and the production of primary materials such as steel,cement,and glass absolutely takes the lead in the world during a considerable period of the past and the future,due to the rapid development of economy and the acceleration of urbanization.In this context,materials production,building construction,and building operation are main factors for the national carbon emissions.Overall,building industry shows higher reduction potentials compared to other sectors,and the energy saving and carbon reduction of building sector is crucial.Accordingly,research on this issue could be socially,scientifically,and practically valuable.At present,the construction of standards for carbon emission assessment has just started in China,relevant analytical frameworks and methods are still not perfect,and no programed software is available for calculation of building emissions.These conditions have hindered the implementation of quantifying the emissions.With consideration of the new requirements for low-carbon building industry in China,the present study focuses on the quantitative analysis of building carbon emissions and the assessment of low-carbon building structures.Relevant research was conducted from the perspectives of provincial buildings,individual buildings,and building structures.The main contents and achievements are as follows:(1)The present study summarized the fundamental concepts and assessment methods for carbon emissions,and divided the building life cycle into four phases incorporating materials production,building construction,building operation,and building disposal.Hierarchical system boundaries were proposed,implementing differential analyses according to the research scopes,scales,and objectives.Furthermore,emission inventories were proposed with respect to materials,energy sources,and services.The improvement of system boundaries and inventories could better guide the collection and sorting of data for building emissions,and provide better supporting conditions for constructing quantitative methods.(2)The principles and methods for investigating the emission factors were proposed,and comprehensive studies of emissions factors for energy,materials,transportation,and economic sectors were made in light of the technical levels of China.Based on literature reviews and inventory analyses,reference values of emission factors for energy and about 140 kinds of commonly used materials were evaluated.Then,the emission factors for railway,road,waterway,and air transportation were analyzed according to the average energy use.Furthermore,the sectoral embodied carbon intensities were estimated using the input-output data.Overall,the research of emission factors could provide significant database for building life cycle assessment.(3)Methods and indicators for life cycle assessment of regional buildings were established based on China's statistical data.Furthermore,methods for allocating building emission permits were proposed based on multi-Gini coefficients,and the decomposition of macro-level targets for emission reduction to the micro-level targets of regional buildings was realized.Further case study showed that,the production and construction phase has contributed significantly to total building emissions in China due to the large amounts of construction and limited production technology,and thus should be emphasized in accomplishing the short-term reduction targets and policy-makings.(4)The quantified methods for building life cycle emission assessment were proposed using the hybrid approach,and the uncertainties of emission assessment were discussed using the semi-parametric probability analyses based on data quality indicators.A case study was made and the results indicated that,conventional methods could significantly underestimate the contribution of embodied emissions to the building life-cycle impacts,without considering the influences of potential energy efficiency and weighted impacts of delayed emissions.Besides,the building life cycle emissions showed obvious uncertainty,and thus system boundaries and model parameters should be carefully decided according to the research objectives.(5)With respect to the importance of controlling production and construction emissions,and the current situation of China's economy and building sector,the present study proposed the framework of building emission quota.The emission quota was implemented and relevant software was programed for Heilongjiang Province.The emission quota could provide supports for the emission assessment during the early stages of design and construction.Furthermore,the approaches for analyzing the emission reduction of buildings were proposed,including the benchmark,optimization,and comparative methods.Then,methods for calculating the carbon reduction in the building life cycle were summarized.A case study was made,the efficiency of the quota system was verified,and the structural performance,economic efficiency,and emissions were compared for reinforced concrete shear wall structure and reinforced concrete block masonry structure.Relevant results indicated the low-carbon feature of the latter structural system.