Effect of building energy efficiency standards on carbon emission efficiency in commercial buildings

The building sector plays a crucial role in the worldwide shift toward achieving net-zero emissions.Building energy efficiency standards(BEESs)are highly effective policies for reducing carbon emissions.Therefore,exploring the provincial variations in carbon emission efficiency(CEE)in the building sector and identifying the effect of BEESs on CEE is crucial.This study focuses on commercial buildings in China and applies a difference in differences model to evaluate the impact of BEESs on the CEE of commercial buildings.The slacks-based measure–data envelopment analysis model is employed to assess the CEE of commercial buildings in 30 Chinese provinces from 2000 to 2019.Furthermore,heterogeneous tests are used to explore how climate characteristics and economic conditions affect the efficiency of BEESs.The results indicate that BEESs positively influence the CEE of commercial buildings.Specifically,a 1%increase in the intensity of BEESs causes a 0.1484%increase in the CEE of commercial buildings.Moreover,the impact of BEESs is particularly pronounced in the southern and western provinces.This study provides valuable scientific evidence for governments to enhance BEESs implementation.

Case Study of Low-carbon Rural Residences and Building Materials

Driven by the policy of "balancing urban and rural development", urbanization in China has been accelerated and agricultural population transferred to urban areas, which guarantees the improvement of life quality and living environment of rural and agricultural population. The urbanization has always been accompanied by national economic development and social progress, relocation and development of rural areas have become a social issue for a certain time. Therefore, it is imperative to explore a series of concrete, well-timed and practical measures for settling rural population, figure out proper modes, materials and methods for rural residence planning and construction under the new conditions, and provide relevant operation and theoretical support. Problems in mountainous rural areas of China were proposed as great population but limited land resources, backward construction techniques, and residences not valuing low carbon or environment protection. In view of these problems, construction techniques suitable for actual conditions of rural areas were explored, energy-saving building materials combined, the style of "dragon sucking water" for mountainous rural areas was proposed, design advantages and details of this architectural model were analyzed.

Carbon foams prepared from coal tar pitch for building thermal insulation material with low cost

A new approach is provided to resolve the large-scale applications of coal tar pitch. Carbon foams with uniform pore size are prepared at the foaming pressure of normal pressure using coal tar pitch as raw materials. The physical and chemical performance of high softening point pitch(HSPP) can be regulated by vacuumizing owing to the cooperation of vacuumizing and polycondensation. Results indicate that the optimum softening point and weight ratio of quinoline insoluble are about 292℃ and 65.7%, respectively. And the optimum viscosity of HSPP during the foaming process is distributed in the range of 1000-10000 Pa·s. The resultant carbon foam exhibits excellent performance, such as uniform pore structure, high compressive strength(4.7 MPa), low thermal conductivity(0.07 W·m^(-1) ·K^(-1)), specially, it cannot be fired under the high temperature of 1200 ℃.Thus, this kind of carbon foam is a potential candidate for thermal insulation material applied in energy saving building.

Low Carbon Building Design Optimization Based on Intelligent Energy Management System

The construction of relevant standards for building carbon emission assessment in China has just started,and the quantitative analysis method and evaluation system are still imperfect,which hinders the development of low-carbon building design.Therefore,the use of intelligent energy management system is very necessary.The purpose of this paper is to explore the design optimization of low-carbon buildings based on intelligent energy management systems.Based on the proposed quantitative method of building carbon emission,this paper establishes the quota theoretical system of building carbon emission analysis,and develops the quota based carbon emission calculation software.Smart energy management system is a low-carbon energy-saving system based on the reference of large-scale building energy-saving system and combined with energy consumption.It provides a fast and effective calculation tool for the quantitative evaluation of carbon emission of construction projects,so as to realize the carbon emission control and optimization in the early stage of architectural design and construction.On this basis,the evaluation,analysis and calculation method of building structure based on carbon reduction target is proposed,combined with the carbon emission quota management standard proposed in this paper.Taking small high-rise residential buildings as an example,this paper compares and analyzes different building structural systems from the perspectives of structural performance,economy and carbon emission level.It provides a reference for the design and evaluation of low-carbon building structures.The smart energy management system collects user energy use parameters.It uses time period and time sequence to obtain a large amount of data for analysis and integration,which provides users with intuitive energy consumption data.Compared with the traditional architectural design method,the industrialized construction method can save 589.22 megajoules(MJ)per square meter.Based on 29270 megajoules(MJ)per ton of standard coal,the construction area of the case is about 8000 m2,and the energy saving of residential buildings is 161.04 tons of standard coal.This research is of great significance in reducing the carbon emission intensity of buildings.

A Pioneering Low Carbon Material Database for Building Industry

Considering that buildings represent 40% of greenhouse gases and approximately 10% of global gross domestic product, the target the building industry has to accomplish is to get to a high quality and low carbon living, by reducing carbon emission by 2050, as said by Energy Performance of Buildings Directive. Considering these needs, designers, manufacturers and construction companies should be able to make use of web and design tools for collecting and inventorying a large variety of environmentally friendly materials, through a specific database that encloses low carbon certified products and eco-labeled ones. The eco-labels are internationally identified as the best tools to encourage the spread of green products and low carbon notions, even if in Europe, there is no specific tool to be used. The project called LoCaMat （Low Carbon Material Database） will act as the first Italian and European database that encompasses multiple data on certified green materials to be used for the construction sector, making buildings climate change resilient, ensuring an efficient use of energy and resources, getting to a complete life cycle assessment for buildings materials and components, encompassing, for the first time, green data and every kind of environmental specs for sustainable design and green practice.

Discussion on low-carbon economy and low-carbon building technology

The paper introduced low-carbon economy and low-carbon technology, and proposed the de-tailed technical measures of low-carbon build-ing technology. Moreover, it has quantitatively calculated the “implicit” CO2 emission of C40 and C50 concrete columns, aluminium curtain wall, wall paintings and common floor decora-tion materials. The calculation results show that it is preferable to use high strength concrete, reduce the usage of aluminium materials and use wooden floor according to location. The paper can be a reference for quantitative meas-urement to the low-carbon technology and en-ergy efficiency.

Building a Low-carbon Development Policy System towards Carbon Neutrality

China has proposed that it will strive to achieve the carbon neutrality target by 2060,providing strategic guidance for China to accelerate the transformation of its development mode and economic restructuring.But it is very challenging to achieve the target.It requires systematic top design as well as scientific formulation of long-term planning,while multiple institutional policies and institutional mechanism reforms need to be strengthened,such as rule of law,administration and economy,to form a systematic and effective incentive and constraint mechanism.Through the exploration and improvement of its three five-year plans,China has formed a low-carbon policy guarantee system led by binding targets,highlighting key industries and regions,and comprising planning,laws,administrative orders,pilot projects,markets,finance and taxation,and other aspects.However,there are still many problems,including the lack of clear policy paths in the near,medium and long term,the absence of key systems such as total carbon emission control system and climate legislation,poor inter-departmental communication and coordination mechanisms,and inadequate systems such as carbon markets and climate investment and financing.Finally,taking into account the current opportunities and challenges,we propose a low-carbon development policy guarantee system for China to move towards carbon neutrality.

Experimental study on thermal environment in large-space building with low sidewall air supply

The thermal environmental characteristics are experim-entally studied in terms of different air supply volumes and outdoor meteorological parameters in a large-space building which is air conditioned with a low sidewall air supply.The experimental results show that the indoor vertical temperature distributions under different condition are similar.The maximum vertical temperature difference（MVTD）is up to about 20 ℃,and it linearly changes with the sol-air temperature.The indoor vertical temperature gradients（VTGs）in the upper,central and lower zones are different.The influence of the sol-air temperature on the VTGs in the upper and the lower zones is greater than that in the central zone.The characteristics of the VTGs in the three zones affected by the air supply volume are the same as those affected by the sol-air temperature.Besides,because of the small air velocity,the predicted mean vote（PMV）on comfort in the occupied zone is slightly high and the air temperature difference between the head and the ankle is usually more than 3 ℃.

INVESTIGATION OF LOW CYCLE FATIGUE BEHAVIOROF BUILDING STRUCTURAL STEELS UNDEREARTHQUAKE LOADING

Based on the failure model of building structural steels under earthquake loading, the low cycle fatigue test at constant strain, the stochastical fatigue test under real earthquake load spectrum and the structural fatigue test are carried out. The experimental results show that microalloying of V Ti and Nb can improve the anti-seismic propersties of steel bars. In the high strain and shori life range, both the static strength and ductility of steels are very important to increasing the low cycle fatigue resistance of steels.

Analysis and forecast of residential building energy consumption in Chongqing on carbon emissions

Carbon emissions mainly result from energy consumption. Carbon emissions inevitably will increase to some extent with economic expansion and rising energy consumption. We introduce a gray theory of quantitative analysis of the energy consumption of residential buildings in Chongqing,China,on the impact of carbon emission factors. Three impacts are analyzed,namely per capita residential housing area,domestic water consumption and the rate of air conditioner ownership per 100 urban households. The gray prediction model established using the Chongqing carbon emission-residential building energy consumption forecast model is sufficiently accurate to achieve a measure of feasibility and applicability.

Properties of Activated Carbons from Sugarcane Leaves and Rice Straw Derived Charcoals by Activation at Low Temperature via KMnO_(4)Pre-Oxidation-Hydrolysis

Activated carbon preparation from sugarcane leaves and rice straw by carbonization(250℃–400℃)and activation at 500℃were studied.The effects of pre-oxidation,hydrolysis of derived charcoals by boiled KMnO4 aqueous solution were evaluated.The derived charcoals products were pretreated using oxidation-hydrolysis with 1–5 wt.%KMnO4 at 100℃and then activated at 500℃.The derived charcoal and activated carbon products were characterized by FTIR,XRD,SEM-EDS and BET.Iodine number and methylene blue number of derived products were also used for the analysis of the products.It was found that fabricated charcoal materials made at 350℃–400℃possess good characteristics with low content of surface functional groups and high carbon content.After pre-oxidation-hydrolysis and activation at 500℃,the resulting derived activated carbon materials from charcoals with 400℃carbonization temperature have high content of oxygen containing surface functional groups such as Mn-O,Si-O,Si-O-Si,C-O,or O-H.In addition,MnO_(2) accumulated on the surface of the derived activated carbon products.The surface area and pore volume of the activated carbon products have also increased with increasing of KMnO_(4) concentration from 1 to 3 wt.%and then decreased with 5 wt.%used during activation.Therefore,activated carbon products made by pre-oxidation-hydrolysis with 3 wt.%KMnO_(4) were used for Fe(Ⅲ)adsorption experiments.It was found that Fe(Ⅲ)adsorption on the activated carbon materials can be fitted with both the Freundlich and the Langmuir models.The calculated maximum Fe(Ⅲ)adsorption capacities of sugarcane leaves derived activated carbon and rice straw derived activated carbon products were 50.00 and 39.37 mg/g,respectively.It was shown that the effect of pre-oxidation-hydrolysis by KMnO_(4) and activation at 500℃are beneficial for activated carbon preparation with environmentally friendly and low-cost simplified operation.

Collaborative robust dispatch of electricity and carbon under carbon allowance trading market

The launch of the carbon-allowance trading market has changed the cost structure of the power industry.There is an asynchronous coupling mechanism between the carbon-allowance-trading market and the day-ahead power-system dispatch.In this study,a data-driven model of the uncertainty in the annual carbon price was created.Subsequently,a collaborative,robust dispatch model was constructed considering the annual uncertainty of the carbon price and the daily uncertainty of renewable-energy generation.The model is solved using the column-and-constraint generation algorithm.An operation and cost model of a carbon-capture power plant(CCPP)that couples the carbon market and the economic operation of the power system is also established.The critical,profitable conditions for the economic operation of the CCPP were derived.Case studies demonstrated that the proposed low-carbon,robust dispatch model reduced carbon emissions by 2.67%compared with the traditional,economic,dispatch method.The total fuel cost of generation decreases with decreasing,conservative,carbon-price-uncertainty levels,while total carbon emissions continue to increase.When the carbon-quota coefficient decreases,the system dispatch tends to increase low-carbon unit output.This study can provide important guidance for carbon-market design and the low-carbon-dispatch selection strategies.

Study of the fatigue fractography of dual phase low carbon steel used in automotive industry

Fatigue properties play a crucial role as they are vital to ensuring the durability and integrity of components subjected to repeated loading conditions over long periods.The main objective of this work is to investigate the fatigue behavior of dual phase low-carbon steels used in automotive applications using a rotating bending fatigue machine.Heat treatments were carried out to analyze the microstructure's effect on the fatigue properties,including quenching low-carbon steel samples at 800℃ and 900℃.Hardness and tensile tests were performed,and the microstructure was inspected to examine the constitute phases.With the assistance of a scanning electron microscope,fractographic analyses were carried out to reveal the fracture features of the samples at different lifetime ranges.The results show that various failure mechanisms occur depending on the stress levels.Additionally,the specimens quenched at 900℃ exhibited higher fatigue strength.

Estimation of Building’s Life Cycle Carbon Emissions Based on Life Cycle Assessment and Building Information Modeling: A Case Study of a Hospital Building in China

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.

Tar formation characteristic of integrated process of coal pyrolysis with dry reforming of low carbon alkane over Ni/La_(2)O_(3)-ZrO_(2)

Coal pyrolysis integrated with dry reforming of low-carbon alkane(CP-DRA)is an effective way to improve tar yield.Ni/La_(2)O_(3)-ZrO_(2) with a La/Zr ratio of 4 was a good catalyst for DRA to inhibit carbon deposition and obtain high tar yield in CP-DRA.In this study,the fraction distribution and component of tars from CP-DRA and coal pyrolysis in N_(2) atmosphere(CP-N_(2))were characterized by using several methods to understand the effect of DRA on coal pyrolysis.The isotope trace method was also used to discuss the role of low-carbon alkane in CP-DRA.The results showed that the tar from CP-N_(2)is mainly composed of aliphatic compounds with more C_(al),H_(al) and CH+CH_(2),and the tar from CP-DRA contains more Car,Har,and CH_(3),and has lower weight-average molecular weight and more light tar content than CP-N_(2).A small amount of C_(2)H_(6) addition in CP-DRA will raise the ratio of H_(β) and CH+CH_(2).Electron paramagnetic resonance(EPR)analysis shows that the tar from CP-DRA has a higher radical concentration while the corresponding char has a lower radical concentration.The isotope trace experiment showed that alkanes provide·H,·CH_(3),etc.to stabilize the radicals from coal pyrolysis and result in more alkyl aromatic compounds during CP-DRA.

Research and Experience Reference on China’s Implementation of Low Carbon Strategy

Economic development has brought about global greenhouse gas emissions, which in turn has brought about global climate change. This research paper aims to compare the strengths and weaknesses that China has demonstrated in the implementation of its low-carbon city strategy and to summarise the valuable experience that China can provide to the world in the implementation of its low-carbon city strategy. This essay analyses in depth the advantages that China has shown in the areas of renewable energy use and government mechanisms, as well as the shortcomings that it has shown in the areas of eco-efficiency industrial structure and capacity upgrading. Then, the paper summarises the successful experiences of the Chinese government in the establishment of renewable energy use and governmental mechanisms, such as the local government’s ability to coordinate multiple sectors (industrial sector, energy sector, etc.) and the implementation of responsibilities. In comparison, the paper also further discusses that China’s implementation of a low-carbon strategy in the future may have more eco-efficiency, industrial structure and capacity upgrading.

Effects of Formation Mineral Compositions on the Performance of High- & Low-Salinity Brine Injection in Carbonate Reservoirs

Low-salinity flooding has been extensively investigated. However, the effects of several variables, such as mineralogical composition, have been neglected. In this regard, the main objective here was to optimize low-salinity water flooding of reservoirs with a wide range of rock mineralogy. Five different brines were determined in reservoirs with different mineral compositions. The mineral composition consisted of limestone and dolomite and the mineralogy varied between 0 and 100% limestone content. The results indicated that the optimum mineralogical system consists of 50% limestone and 50% dolomite flooded with 100% diluted formation brine. Additionally, reservoir mineral composition plays a significant role in the performance of low-salinity water flooding. The findings here will improve our understanding of rock composition effects on the performance of low-salinity water flooding and provide the industry with data that can scientifically improve process optimization.

The Structural Behavior of Low/Medium/High Rise Concrete Office Buildings in Kuwait

The main concern of this paper is to provide an extensive study for the structural behavior of low/medium/high rise office buildings aiming to deepen structure and architect designers understanding for such type of buildings. The study is performed on reinforced concrete and emphasized only on Kuwait city conditions for wind. Regular layout plan building with different heights ranging from five to fifty typical office stories are investigated in this study. Three dimensional finite element techniques through ETABS software are used in conducting analysis for structures presented here-in. A serviceability study is performed to ensure that buildings have sufficient stability to limit lateral drift and peak acceleration within the acceptable range of occupancy comfort. In addition, an ultimate strength study is carried out to design and verify that all the structural elements are designed to withstand factored gravity and lateral loadings in a safe manner according to the international building codes. The building slenderness ratio and the building core size and location are the studied parameters since they are the key drivers for the efficient structural design. Analysis results are presented and discussed and finally conclusions are summarized as guidelines for designers of concrete office buildings in Kuwait.

Preparation of Styrene-acrylate Latex Used in Ultralow VOC Building Internal Wall Coating

Styrene-acrylate latex with high glass transition temperature （T）, low minimum film forming temperature（MFT） and good stability was prepared via core-shell emulsion polymerization. With semicontinuous process, high conversion rate of monomer and low gel rate were achieved. The weight ratio of core monomer to shell monomer was approximately 1.35. It is found that many factors such as emulsifiers, initiators, reaction temperature, pH value and polymerization technology have influences on the permormance of styrene-acrylate latex. The prepared latex was characterized by TEM and FTIR. The obtained latex with T of 20.57 ℃, MFT or5.0 ℃, and good stability, had good stability of film forming.

Properties and Characterization of Two Clays Raw Material from Mountain District (West of Côte d’Ivoire) for Use in Low-Carbon Cements

This work was devoted to the study of the physico-chemical properties of two clay minerals from the Mountain District (West Côte d'Ivoire) referenced ME1 and ME2. These samples were characterized by the experimental techniques, such as X-ray diffraction (XRD), Infrared spectroscopy (IR), Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), Differential Thermal Analysis and Thermogravimetry (DTA-TG), Brunauer, Emett and Teller method (BET), laser particle size analysis and Scanning Electron Microscope (SEM). The main results of these analyses reveal that the two clay samples mainly contain quartz (52.91% for ME1 and 51.72% for ME2), kaolinite (36.60% for ME1 and 41.6% for ME2) and associated phases, namely goethite and hematite (13.47% for ME1 and 11.00% for ME2). The specific surface values obtained for samples ME1 and ME2 are 34.78 m2/g and 29.18 m2/g respectively. The results obtained show that the samples studied belong to the kaolinite family. After calcination, they could have good pozzolanic activity and therefore be used in the manufacture of low-carbon cements.