Throughout the life cycle, the buildings emit a great deal of carbon dioxide into the atmosphere, which directly leads to aggravation in the greenhouse effect and becomes a severe threat to the environment and humans....Throughout the life cycle, the buildings emit a great deal of carbon dioxide into the atmosphere, which directly leads to aggravation in the greenhouse effect and becomes a severe threat to the environment and humans. Researchers have made numerous efforts to accurately calculate emissions to reduce the life cycle carbon emissions of residential buildings. Nevertheless, there are still difficulties in quickly estimating carbon emissions in the design stage without specific data. To fill this gap, the study, based on Life Cycle Assessment (LCA) and Building Information Modeling (BIM), proposed a quick method for estimating Building’s Life Cycle Carbon Emissions (BLCCE). Taking a hospital building in Chuzhou City, Anhui Province, China as an example, it tested its possibility to estimate BLCCE. The results manifested that: 1) the BLCCE of the project is 40,083.56 tCO2-eq, and the carbon emissions per square meter per year are 119.91 kgCO2-eq/(m2·y);2) the stage of construction, operational and demolition account for 7.90%, 91.31%, and 0.79% of BLCCE, respectively;3) the annual carbon emissions per square meter of hospital are apparently higher than that of villa, residence, and office building, due to larger service population, longer daily operation time, and stricter patient comfort requirements. Considering the lack of BLCCE research in Chinese hospitals, this case study will provide a valuable reference for the estimated BLCCE of hospital building.展开更多
The large amount of carbon emissions generated by buildings during their life cycle greatly impacts the environment and poses a considerable challenge to China’s carbon reduction efforts.The building design phase has...The large amount of carbon emissions generated by buildings during their life cycle greatly impacts the environment and poses a considerable challenge to China’s carbon reduction efforts.The building design phase has the most significant potential to reduce building life-cycle carbon emissions(LCCO_(2)).However,the lack of detailed inventory data at the design stage makes calculating a building’s LCCO_(2) very difficult and complex.Therefore,accurate prediction of building LCCO_(2) at the design stage using relevant design factors is essential to reduce carbon emissions.This paper proposes an ensemble learning algorithm combining Bayesian optimization and extreme gradient boosting(BO-XGBoost)to predict LCCO_(2) accurately in residential buildings.First,this study collected and calculated the LCCO_(2) of 121 residential buildings in Chengdu,China.Second,a carbon emission prediction model was developed using XGBoost based on 15 design factors,and hyperparameter optimization was performed using the BO algorithm.Finally,the model performance was evaluated using two evaluation metrics,coefficient of determination(R2)and root mean square error(RMSE),and the prediction performance of other models was compared with that of the BO-XGBoost model.The results show that the RMSE of the proposed BO-XGBoost for predicting LCCO_(2) in residential buildings is at least 40%lower compared to other models.The method adopted in this study can help designers accurately predict building LCCO_(2) at the early design stage and provide methodological support for similar studies in the future.展开更多
Buildings are known to significantly affect the global carbon emissions throughout their life cycle. To mitigate carbon emissions, investigation of the current performance of buildings with regard to energy consumptio...Buildings are known to significantly affect the global carbon emissions throughout their life cycle. To mitigate carbon emissions, investigation of the current performance of buildings with regard to energy consumption and carbon emissions is necessary. This paper presents a process-based life cycle assessment methodology for assessing carbon emissions of buildings, using a multistorey reinforced concrete building in a Sri Lankan university as a case study. The entire cradle-to-grave building life cycle was assessed and the life span of the building was assumed as 50 years. The results provide evidence of the significance of operation and material production stages, which contributed to the total carbon emissions by 63.22% and 31.59% respectively. Between them, the main structural materials, concrete and reinforcement steel made up 61.91% of the total carbon emitted at the material production stage. The life cycle carbon emissions of the building were found to be 31.81 kg·m^(–2) CO_2 per year, which is comparable with the values obtained in similar studies found in the literature. In minimizing the life cycle carbon emissions, the importance of identifying control measures for both building operation and material production at the early design stage were emphasized. Although the other life cycle stages only contributed to about 5.19% of the life cycle carbon emissions, they should also receive attention when formulating control strategies. Some of the recommended strategies are introducing energy efficiency measures in building design and operation, using renewable energy for building operation and manufacturing of materials,identifying designs that can save mass material quantities,using alternative materials that are locally available in Sri Lanka and implementing material reuse and recycling.This study is one of the first to undertake a life cycle carbon emissions assessment for a building in the Sri Lankan context, with the hope of facilitating environmentallyfriendly buildings and promoting sustainable construction practices in the country.展开更多
Studies on building carbon emissions focus mainly on the materialization phase of life cycle, as carbon emissions in this stage is intensive and high. This paper proposes a simplified model to calculate embodied carbo...Studies on building carbon emissions focus mainly on the materialization phase of life cycle, as carbon emissions in this stage is intensive and high. This paper proposes a simplified model to calculate embodied carbon emissions in building design stage by conducting a process-based inventory analysis of carbon emissions from materials used in 129 residential buildings, 41 office buildings, and 21 commercial buildings during materialization phase. The results indicate that average carbon emissions per unit area from building materials used in residential buildings, office buildings, and commercial buildings are 514.66 kgCO2 e/m2, 533.69 kg CO2 e/m2 and 494.19 kgCO2 e/m2, respectively. Besides, ten kinds of building materials(namely, steel, commercial concrete, wall building materials, mortar, copper core cables, architectural ceramics, PVC pipes, thermal insulation materials, doors and windows, and water paint) constitute 99% of total carbon emissions in all three types of buildings. These materials are major carbon emissions sources in materialization phase. Thus, embodied carbon emissions can be significantly reduced by limiting the amount of these materials in architectural design as well as by using environmental friendly materials.展开更多
文摘Throughout the life cycle, the buildings emit a great deal of carbon dioxide into the atmosphere, which directly leads to aggravation in the greenhouse effect and becomes a severe threat to the environment and humans. Researchers have made numerous efforts to accurately calculate emissions to reduce the life cycle carbon emissions of residential buildings. Nevertheless, there are still difficulties in quickly estimating carbon emissions in the design stage without specific data. To fill this gap, the study, based on Life Cycle Assessment (LCA) and Building Information Modeling (BIM), proposed a quick method for estimating Building’s Life Cycle Carbon Emissions (BLCCE). Taking a hospital building in Chuzhou City, Anhui Province, China as an example, it tested its possibility to estimate BLCCE. The results manifested that: 1) the BLCCE of the project is 40,083.56 tCO2-eq, and the carbon emissions per square meter per year are 119.91 kgCO2-eq/(m2·y);2) the stage of construction, operational and demolition account for 7.90%, 91.31%, and 0.79% of BLCCE, respectively;3) the annual carbon emissions per square meter of hospital are apparently higher than that of villa, residence, and office building, due to larger service population, longer daily operation time, and stricter patient comfort requirements. Considering the lack of BLCCE research in Chinese hospitals, this case study will provide a valuable reference for the estimated BLCCE of hospital building.
基金supported by the National Natural Science Foundation of China (No.52078442)the China Scholarship Council.
文摘The large amount of carbon emissions generated by buildings during their life cycle greatly impacts the environment and poses a considerable challenge to China’s carbon reduction efforts.The building design phase has the most significant potential to reduce building life-cycle carbon emissions(LCCO_(2)).However,the lack of detailed inventory data at the design stage makes calculating a building’s LCCO_(2) very difficult and complex.Therefore,accurate prediction of building LCCO_(2) at the design stage using relevant design factors is essential to reduce carbon emissions.This paper proposes an ensemble learning algorithm combining Bayesian optimization and extreme gradient boosting(BO-XGBoost)to predict LCCO_(2) accurately in residential buildings.First,this study collected and calculated the LCCO_(2) of 121 residential buildings in Chengdu,China.Second,a carbon emission prediction model was developed using XGBoost based on 15 design factors,and hyperparameter optimization was performed using the BO algorithm.Finally,the model performance was evaluated using two evaluation metrics,coefficient of determination(R2)and root mean square error(RMSE),and the prediction performance of other models was compared with that of the BO-XGBoost model.The results show that the RMSE of the proposed BO-XGBoost for predicting LCCO_(2) in residential buildings is at least 40%lower compared to other models.The method adopted in this study can help designers accurately predict building LCCO_(2) at the early design stage and provide methodological support for similar studies in the future.
文摘Buildings are known to significantly affect the global carbon emissions throughout their life cycle. To mitigate carbon emissions, investigation of the current performance of buildings with regard to energy consumption and carbon emissions is necessary. This paper presents a process-based life cycle assessment methodology for assessing carbon emissions of buildings, using a multistorey reinforced concrete building in a Sri Lankan university as a case study. The entire cradle-to-grave building life cycle was assessed and the life span of the building was assumed as 50 years. The results provide evidence of the significance of operation and material production stages, which contributed to the total carbon emissions by 63.22% and 31.59% respectively. Between them, the main structural materials, concrete and reinforcement steel made up 61.91% of the total carbon emitted at the material production stage. The life cycle carbon emissions of the building were found to be 31.81 kg·m^(–2) CO_2 per year, which is comparable with the values obtained in similar studies found in the literature. In minimizing the life cycle carbon emissions, the importance of identifying control measures for both building operation and material production at the early design stage were emphasized. Although the other life cycle stages only contributed to about 5.19% of the life cycle carbon emissions, they should also receive attention when formulating control strategies. Some of the recommended strategies are introducing energy efficiency measures in building design and operation, using renewable energy for building operation and manufacturing of materials,identifying designs that can save mass material quantities,using alternative materials that are locally available in Sri Lanka and implementing material reuse and recycling.This study is one of the first to undertake a life cycle carbon emissions assessment for a building in the Sri Lankan context, with the hope of facilitating environmentallyfriendly buildings and promoting sustainable construction practices in the country.
基金supported by the China Postdoctoral Science Foundation (Grant No. 2017M613086)Key Theoretical and Practical Research Fund of Shaanxi Social Sciences(Grant No. 2018Z040)+2 种基金Shaanxi Ministry of Construction-Technology Development Plan (2016-RZ54)Project of Science and Technology Plan of Ministry of Housing Urban-Rural Construction (UDC2017032312)“the 13th Five-Year” National Science and Technology Major Project of China (No. 2018YFC0704500)
文摘Studies on building carbon emissions focus mainly on the materialization phase of life cycle, as carbon emissions in this stage is intensive and high. This paper proposes a simplified model to calculate embodied carbon emissions in building design stage by conducting a process-based inventory analysis of carbon emissions from materials used in 129 residential buildings, 41 office buildings, and 21 commercial buildings during materialization phase. The results indicate that average carbon emissions per unit area from building materials used in residential buildings, office buildings, and commercial buildings are 514.66 kgCO2 e/m2, 533.69 kg CO2 e/m2 and 494.19 kgCO2 e/m2, respectively. Besides, ten kinds of building materials(namely, steel, commercial concrete, wall building materials, mortar, copper core cables, architectural ceramics, PVC pipes, thermal insulation materials, doors and windows, and water paint) constitute 99% of total carbon emissions in all three types of buildings. These materials are major carbon emissions sources in materialization phase. Thus, embodied carbon emissions can be significantly reduced by limiting the amount of these materials in architectural design as well as by using environmental friendly materials.
