Research On Carbon Emission Calculation And Economic Evaluation Of Fabricated Buildings In Materialization Stage

With the development of human society,the greenhouse effect problem is becoming more and more serious,and reducing greenhouse gas emissions has become a general consensus of the international community.China made a solemn commitment to the world at the 75 th UN General Assembly to strive to achieve peak carbon dioxide emissions before 2030 and carbon neutrality before 2060.Construction industry as a traditional carbon emitter,according to the United Nations Environment Programme calculations,the construction industry consumes about 30% ～ 40% of the world’s energy,while emitting almost 30% of the world’s greenhouse gases,so the low-carbon emission reduction of the construction industry is an important means for the country to achieve the "3060" strategic goals,the construction business must accelerate the transformation to green development,and as an important pillar of the national economy,it is necessary to ensure the stable and healthy development of the industry while reducing emissions.In this context,prefabricated buildings have become the development direction of the transformation and upgrading of the construction industry due to their green,low-carbon and efficient characteristics,and have received strong support from the state.In the process of promoting prefabricated buildings,not only to reduce carbon dioxide emissions,but also to guide the sustainable development of the industry,so it is necessary to quantitatively evaluate the carbon emissions and economy of prefabricated buildings.Taking prefabricated buildings as the research object,this paper studies the carbon emissions and economy in the prefabricated building materialization stage on the basis of analyzing the development of prefabricated buildings at home and abroad,the research status of building carbon emissions,carbon emission value methods and related carbon emission and economic evaluation methods,and the main research content and achievements include the following aspects:(1)The calculation method of carbon emissions in the materialization stage of prefabricated buildings is given.Firstly,it is clarified that the prefabricated building materialization stage includes five stages: building materials production,building materials transportation,component production,component transportation and on-site construction,on the basis of traditional building carbon emission measurement,combined with the characteristics of prefabricated buildings,determine the calculation boundary,give the carbon emission calculation formula of each stage,and explain the basic information sources such as carbon emission factors.(2)The economic evaluation model of prefabricated building materialization stage is established.In the traditional program evaluation,the impact of carbon dioxide emissions is rarely considered,and this paper applies the marginal carbon emission reduction cost of the construction industry to value the carbon dioxide emissions,and proposes a comprehensive economic evaluation method model of prefabricated buildings,taking the comprehensive cost including carbon cost as the evaluation index.(3)Calculate the cost of carbon marginal emission reduction in the construction industry.Through the collation and summary of the value-based methods of relevant carbon emissions,the marginal carbon emission reduction cost of China’s construction industry was determined to be selected as the unit price of carbon emissions,after relevant data collection and processing,it is calculated that during 2011～2020,the total carbon emissions of China’s construction industry showed a trend of fluctuation and decline,with an average annual reduction rate of 7.01% and an annual average carbon emission of 1311.657 million tons;in terms of the cost of marginal carbon emission reduction in the construction industry,in 2011～2020,the average carbon marginal emission reduction cost of China’s construction industry was 11,300 yuan / ton,which means that every 1 ton of carbon dioxide emissions reduced by the construction industry will lead to a total output value decrease of 11,300 yuan,From the situation of various provinces,the data distribution is uneven and the differences between regions are large,showing the distribution trend of high north and low south on the whole.(4)Analyze the traditional cost of prefabricated buildings.The cost composition of prefabricated buildings was sorted out,and the calculation range,pricing basis and pricing method of traditional costs of prefabricated buildings were expounded.(5)Take a prefabricated building in Shenzhen as an example to conduct research.The calculation results of carbon emissions in the materialization stage show that the carbon emissions in the raw material production stage account for the highest proportion,about 85%,so it should be the focus stage of low-carbon emission reduction.The comprehensive economic evaluation and analysis results of the two assembly schemes A and B show that the traditional higher cost of the A scheme has relatively little carbon dioxide emissions in the materialization stage,resulting in a low comprehensive cost,so from the perspective of low carbon,considering the impact of carbon dioxide emissions,plan A will be more suitable for the current green development theme of the construction industry.The evaluation method of carbon emissions calculation and economy in the prefabricated building materialization stage provided in this paper can provide reference for the inclusion of quantitative indicators of carbon dioxide emission economic benefits in the prefabricated building evaluation system in the future,and can also provide reference for architects when optimizing assembly schemes,and has certain practical significance for the low-carbon and healthy development of prefabricated buildings.