• Journal of the Korean Society of Safety
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• v.27 no.3
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• pp.1-8
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• 2012

Characteristics of smoke emission in light duty diesel vehicles was investigated according to the year of production, engine displacement volume, and mileage. The smoke emission was measured using light extinction smoke measurement method under free acceleration test mode. Total number of the tested vehicles was 180. The year of production of the tested vehicles distributed from 2002 to 2007. The displacement volumes of the tested vehicles were categorized as 2-liter, 2.5-liter, 2.7-liter, and 3-liter. The mileage of the tested vehicles distributed from 20,000 km to 400,000 km. The more recent in the year of production of the tested vehicles did not show clearly lower in smoke emissions. Smoke emission showed different values according to driver's pedal pushing pattern. Also, smoke emission peak for each free acceleration test initially increased and reach a maximum of the peak values. Afterwards, the smoke peak gradually decreased as number of test increased. A new guide line was proposed to determine the smoke value from the light duty diesel vehicles based on smoke emission peak patterns which were obtained with several repeated free acceleration tests.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.4
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• pp.559-568
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• 2013

Increased worldwide concerns about fossil fuel costs and effects on the environment lead many governments and scientific societies to consider the hydrogen as the fuel of the future. Many researches have been made to assess the suitability of using the hydrogen gas as fuel for internal combustion engines and gas turbines; this suitability was assessed from several viewpoints including the combustion characteristics, the fuel production and storage and also the thermodynamic cycle changes with the application of hydrogen instead of ordinary fossil fuels. This paper introduces the basic environmental differences happening when changing the fuel of a marine gas turbine from marine diesel fuel to gaseous hydrogen for the same power output. Environmentally, the hydrogen is the best when the $CO_2$ emissions are considered, zero carbon dioxide emissions can be theoretically attained. But when the $NO_x$ emissions are considered, the hydrogen is not the best based on the unit heat input. The hydrogen produces 270% more $NO_x$ than the diesel case without any control measures. This is primarily due to the increased air flow rate bringing more nitrogen into the combustion chamber and the increased combustion temperature (10% more than the diesel case). Efficient and of course expensive $NO_x$ control measures are a must to control these emissions levels.

• KIEAE Journal
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• v.14 no.1
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• pp.131-138
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• 2014

The recent interests in securing alternative resource have increased due to environmental issues and exhaustion of natural resources. The government notices production of recycled aggregate using waste concrete as the substitute of the natural aggregate. However, It's important to reduce environmental burden being inevitably made in the process producing recycled aggregate. In this study, the scenarios of transportation distance were set in the transportation phase of production of recycled aggregate. In addition, The possibility of emissions and reduction of carbon dioxide were studied depending on the scenarios. For this study, data about a amount of waste concrete, transportation distance, kind of vehicle, the number of required vehicle, fuel efficiency of vehicle and etc were gathered from 15 companies of intermediate treatment and 60 constructions sites located in Daegu city and Kyungpook area. Based on those data, fuel consumptions and $CO_2$ emissions according to the transportation scheme of waste concrete were calculated. As a result of the study, the emission of carbon dioxide was possible to be reduced by 27.8~75.4% depending on the scenarios of transportation distance.

• Journal of Animal Science and Technology
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• v.64 no.4
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• pp.770-781
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• 2022

Meteorological disasters caused by climate change like heat, cold waves, and unusually long rainy seasons affect the milk productivity of cows. Studies have been conducted on how milk productivity and milk compositions change due to heat stress (HS). However, the estimation of losses in milk production due to HS and hereby environmental impacts of greenhouse gas (GHG) emissions are yet to be evaluated in Korean dairy farms. Dairy milk production and milk compositions data from March to October 2018, provided by the Korea Dairy Committee (KDC), were used to compare regional milk production with the temperature-humidity index (THI). Raw data for the daily temperature and relative humidity in 2018 were obtained from the Korea Meteorological Administration (KMA). This data was used to calculate the THI and the difference between the maximum and minimum temperature changing rate, as the average daily temperature range, to show the extent to which the temperature gap can affect milk productivity. The amount of milk was calculated based on the price of 926 won/kg from KDC. The results showed that the average milk production rate was the highest within the THI range 60-73 in three regions in May: Chulwon (northern region), Hwasung (central region), and Gunwi (southern region). The average milk production decreased by 4.96 ± 1.48% in northern region, 7.12 ± 2.36% in central region, and 7.94 ± 2.57% in southern region from June to August, which had a THI range of 73 or more, when compared to May. Based on the results, the level of THI should be maintained like May. If so, the farmers can earn a profit of 9,128,730 won/farm in northern region, 9,967,880 won/farm in central region, and 12,245,300 won/farm in southern region. Additionally, the average number of cows raised can be reduced by 2.41 ± 0.35 heads/farm, thereby reducing GHG emissions by 29.61 ± 4.36 kg CO₂eq/day on average. Overall, the conclusion suggests that maintaining environmental conditions in the summer that are similar to those in May is necessary. This knowledge can be used for basic research to persuade farmers to change farm facilities to increase the economic benefits and improve animal welfare.

• International Journal of Automotive Technology
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• v.4 no.2
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• pp.77-86
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• 2003

How to compare the environmental damage caused by vehicles with different foe]s and drive trains\ulcorner This paper describes a methodology to assess the environmental impact of vehicles, using different approaches, and evaluating their benefits and limitations. Rating systems are analysed as tools to compare the environmental impact of vehicles, allowing decision makers to dedicate their financial and non-financial policies and support measures in function of the ecological damage. The paper is based on the "Clean Vehicles" research project, commissioned by the Brussels Capital Region via the BIM-IBGE (Brussels Institute for the Conservation of the Environment) (Van Mierlo et at., 2001). The VriJe Universiteit Brussel (ETEC) and the universite Libre do Bruxelles (CEESE) have jointly carried out the workprogramme. The most important results of this project are illustrated in this paper. First an overview of environmental, economical and technical characteristics of the different alternative fuels and drive trains is given. Afterward the basic principles to identify the environmental impact of cars are described. An outline of the considered emissions and their environmental impact leads to the definition of the calculation method, named Ecoscore. A rather simple and pragmatic approach would be stating that all alternative fuelled vehicles (LPG, CNG, EV, HEV, etc.) can be considered as ′clean′. Another basic approach is considering as ′clean′ all vehicles satisfying a stringent omission regulation like EURO IV or EEV. Such approaches however don′t tell anything about the real environmental damage of the vehicles. In the paper we describe "how should the environmental impact of vehicles be defined\ulcorner", including parameters affecting the emissions of vehicles and their influence on human beings and on the environment and "how could it be defined \ulcorner", taking into account the availability of accurate and reliable data. We take into account different damages (acid rain, photochemical air pollution, global warming. noise, etc.) and their impacts on several receptors like human beings (e.g., cancer, respiratory diseases, etc), ecosystems, or buildings. The presented methodology is based on a kind of Life Cycle Assessment (LCA) in which the contribution of all emissions to a certain damage are considered (e.g. using Exposure-Response damage function). The emissions will include oil extraction, transportation refinery, electricity production, distribution, (Well-to-Wheel approach), as well as the emission due to the production, use and dismantling of the vehicle (Cradle-to-Grave approach). The different damages will be normalized to be able to make a comparison. Hence a reference value (determined by the reference vehicle chosen) will be defined as a target value (the normalized value will thus measure a kind of Distance to Target). The contribution of the different normalized damages to a single value "Ecoscore" will be based on a panel weighting method. Some examples of the calculation of the Ecoscore for different alternative fuels and drive trains will be calculated as an illustration of the methodology.

• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.225-232
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• 2024

The reduction of CO₂ emissions in the energy production sector, which accounts for 86.8% of total greenhouse gas emissions, is important to achieve carbon-neutrality. At present, 60% of total power generation in South Korea is coal and natural gas. Replacing fossil fuel with renewable energy such as wind and solar has disadvantages of unstable energy supply and high costs. Therefore, this study was conducted through the co-firing of natural gas, ammonia and hydrogen utilizing the natural gas combined cycle process. The results demonstrated reduction in CO₂ emissions and 34%~238% of the power production compared to using only natural gas. Case studies on mass fractions of natural gas, ammonia and hydrogen indicated that power production and NO_x emissions were inversely proportional to the ammonia ratio and directly proportional to the hydrogen ratio. This study provides guidelines for the use of various fuel mixtures and economic analysis in co-firing power generation.

• Journal of the Korea Institute of Building Construction
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• v.22 no.2
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• pp.137-148
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• 2022

Recently, in the concrete industry, the development and commercialization of low-carbon products of ready-mixed concrete have emerged as part of the efforts to realize carbon neutrality. This study aims to investigate the current status of environmental product declaration(EPD) of ready-mixed concrete and to analyze the characteristics of carbon emissions by compressive strength, life cycle stage, and region. To this end, the related certification system requiring the calculation of carbon emissions in the concrete industry was analyzed. The target of analyzing the current status of carbon emissions was set as a product of ready-mixed concrete that acquired EPD certification based on the life cycle assessment method. In addition, the trend of carbon emissions according to each characteristic was reviewed by analyzing carbon emissions by the life cycle of ready-mixed concrete products, analyzing carbon emissions by standard, and analyzing carbon emissions by region. As a result, the carbon emissions in the pre-production stage were 99% compared to total carbon emissions., and as it increased from 18MPa to 40MPa, carbon emissions also increased. Even with the same specifications, the carbon emissions in the capital region were higher than in the southern region.

• New & Renewable Energy
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• v.20 no.1
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• pp.145-174
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• 2024

Addressing climate change necessitates evidence-based policies grounded in science. The use of forest biomass for energy production is based on a broad scientific consensus at the international level. However, some environmental groups in South Korea are opposing this system of energy production. Through this study, the authors aim to reduce unnecessary confusion and foster an atmosphere conducive to meaningful evidence-based policies. We have classified the issue into eight categories: biological carbon cycle, carbon debt, nature-based solutions, air emissions, cascading principles and sustainability certification, forest environmental impacts, climate change litigation, and the behavior of environmental groups and public perception. Consequently, the following key points were derived: (1) the actions of some environmental groups seem to follow a similar pattern to denialist behavior that denies climate change and climate science; (2) the quality of evidence for campaigns that oppose the use of forest biomass for energy production is low, with a tendency to overgeneralize information, high uncertainty, and difficulty in finding new claims.; (3) most of the public believes that forest biomass energy is necessary, and the governments of major countries are aware of its importance. Significantly, Forest biomass for energy is based on an overwhelming level of scientific consensus recognized internationally.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.215-216
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• 2012

Emissions of CO₂ occur during the production of cement manufacturing process. During the production of clinker, limestone is mainly calcium carbonate, is heated to produce lime and CO₂ as a by-product. It has a major problem, CO₂ uptake is not considered in concrete carbonation, just focus in CO₂ emission. This study is to develop a simulation model for CO₂ uptakes in concrete structures based on carbonation reduction coefficient considering finishing materials. CO₂ uptakes unit of concrete cubic meter is calculated by CO₂ emissions unit of concrete materials and usage of concrete materials in mix proportion. From the simulation result, CO₂ uptake ratios is 2.04 percent in carbonation models of concrete structure during 40 years.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1288-1294
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• 2022

Hydrogen as an environmentally friendly energy carrier has received special attention to solving uncertainty about the presence of renewable energy and its dependence on time and weather conditions. This material can be prepared from different sources and in various ways. In previous studies, fossil fuels have been used in hydrogen production, but due to several limitations, especially the limitation of the access to this material in the not-too-distant future and the great problem of greenhouse gas emissions during hydrogen production methods. New methods based on renewable and green energy sources as energy drivers of hydrogen production have been considered. In these methods, water or biomass materials are used as the raw material for hydrogen production. In this article, after a brief review of different hydrogen production methods concerning the required raw material, these methods are examined and ranked from different aspects of economic, social, environmental, and energy and exergy analysis sustainability. In the following, the current position of hydrogen production is discussed. Finally, according to the introduced methods, their advantages, and disadvantages, solar electrolysis as a method of hydrogen production on a small scale and hydrogen production by thermochemical method on a large scale are introduced as the preferred methods.