Research On Life Cycle Carbon Footprint And Carbon Sink Absorption Assessment Of Prefabricated Buildings

The global average temperature in 2022 is about 1.67°C higher than before the Industrial Revolution.In order to solve the current global warming problem caused by excessive greenhouse gas emissions,China has proposed the "dual carbon" strategic goal and a coordinated pollution reduction and carbon reduction governance plan,which is conducive to promoting the formation of green production methods in various industries.With the advantages of waste efficiency,energy saving and less environmental pollution,prefabricated construction has become a favourable way for the construction industry to move towards industrialisation,standardisation and greening,and will become an important grip for the future development of the construction industry.In this context,research on the key sources of life cycle carbon footprint of prefabricated buildings and carbon sinks,and give strategies to reduce sources and increase sinks,which is of reference significance for the realization of energy conservation and carbon reduction goals of China’s construction industry.Based on life cycle assessment and “source sink” theory,this thesis takes the life cycle carbon footprint distribution and carbon sequestration capacity of prefabricated buildings as the research object.Firstly,the activities that generate carbon footprints in each stage and the scope of carbon sink system are analyzed in detail,and the carbon footprint and carbon sequestration assessment model of prefabricated buildings in each stage and life cycle is constructed based on the carbon emission coefficient method.Secondly,a prefabricated building in Shaanxi Province is selected as practical case.Based on BIM and Dest-h software,the parameter data of the evaluation model is obtained,and the life cycle carbon footprint and carbon sequestration of prefabricated buildings are calculated to verify the effectiveness and applicability of the model,explore the distribution characteristics and key sources of life cycle carbon footprint of prefabricated buildings,and analyze the carbon sequestration capacity.Finally,based on summarizing the distribution of carbon footprint and the amount of carbon sequestration,energy-saving and carbon reduction methods for each stage are proposed from two aspects: reducing carbon footprint of source and enhancing carbon sequestration capacity.The life cycle carbon footprint and carbon sequestration assessment model of prefabricated buildings established in this study can provide reference for other prefabricated buildings to conduct carbon footprint and carbon sequestration analysis in the design phase.And through the analysis of the distribution characteristics of the carbon footprint of prefabricated buildings and the carbon sequestration capacity of the carbon sink system,the strategy of reducing sources and increasing sinks is formed,which provides a reference for prefabricated building participants to formulate and implement specific carbon emission reduction strategies.The main findings are:(1)Prefabricated buildings are superior in terms of carbon footprint reduction.Compared to traditional construction methods,the carbon footprint per unit area of a prefabricated building is reduced by 1.50%.(2)The production stage of building materials with concentrated emissions and high emission intensity is the main focus of the construction industry to achieve short-term energy-saving and emission reduction goals,and the operation and maintenance stage is always the key object for the future construction industry to achieve energy-saving and emission reduction goals.(3)For prefabricated residential buildings located in cold B zones,cooling,heating and lighting activities are the main source of their whole life cycle carbon footprint,accounting for over80%.(4)The annual carbon footprint of prefabricated buildings first decreases and then continues to increase as their service life increases,taking into account equipment upgrades and ageing,building materials and equipment damage during the operation and maintenance phase of prefabricated buildings.(5)The carbon sequestration benefits of the carbon sink system for prefabricated buildings are obvious,and green vegetation is the best choice for achieving energy saving and emission reduction goals in the carbon sink system.