Research On Carbon Reduction Strategies For The Whole Life Cycle Of Small And Medium Sized Office Buildings In Xi’an City

After the concept and goal of carbon peaking and carbon neutrality were proposed,how to achieve this goal has always been the focus of research efforts by numerous professionals in the HVAC industry.With the deepening of urbanization,public buildings in cities are still unable to meet the demand and continue to grow rapidly.As one of the important areas for building energy conservation and low-carbon development,public buildings play a significant role in achieving low-carbon construction.Compared to large-scale public buildings,there are a large number of small and medium-sized office buildings in cities,many of which were built about 10years ago when there were no clear requirements for carbon emissions standards.Managing the carbon emissions of these buildings will be a challenging task for optimizing and managing carbon emissions in the future.This article,based on the theory of life cycle assessment,compares the carbon emission calculation methods used in commonly used carbon emission guidelines in China and abroad.Finally,the carbon emission coefficient method is adopted to design the mathematical model.The carbon emission factors of various factors within the system boundary are determined,and the data required for the calculation model is improved.The carbon emission calculation books for three stages of XA-1 target building（material production stage,construction and installation stage,building use stage,and building end-of-life stage）are obtained,and the results are analyzed and compared preliminarily.In light of the characteristics of the target building’s energy consumption and carbon emissions,we chose to start from the operational stage and technical optimization,coupling distributed photovoltaics and energy storage modules with the existing building design and introducing new energy supply logic.Using Designbuilder and GABI software,we conducted comprehensive simulations of the target building and analyzed the results before and after optimization.The findings showed that the annual carbon emissions before optimization in the operational stage were 487.15 t CO₂/a,and after optimization,it decreased to 372.14 t CO₂/a,resulting in a reduction of 115.01t CO₂/a and an optimization rate of 23.6%.Subsequently,an economic analysis of the optimization was performed based on carbon trading market prices and the annual electricity pricing policy in Xi’an,with a calculated payback period of 5.2 years.The lifecycle carbon emissions of steel and concrete,the two most significant building materials,were verified using GABI software and compared with the results obtained in Chapter 3,showing a discrepancy of 4.7%and 2.1%,respectively,which falls within an acceptable range and validates the accuracy of the calculations.Based on the sensitivity index of carbon emissions,12 optimization strategies for reducing carbon emissions in various aspects of the target building were analyzed and proposed.The impact of different strategies on carbon emissions was ranked.The results showed that the highest reduction in carbon emissions and sensitivity was achieved by increasing the building’s lifespan.Other strategies with significant optimization effects（sensitivity greater than 5%）included optimizing the structural system,using green building materials,optimizing the form factor coefficient,and coupling renewable energy systems.In addition,the least effective strategy in terms of sensitivity was the use of green construction methods,with a reduction of only 0.28%.