• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.332-340
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• 2017

This study aims to propose a new optimization-based approach for design and analysis of the stand-alone hybrid energy supply system using renewable energy sources (RES). In the energy supply system, we include multiple energy production technologies such as Photovoltaics (PV), Wind turbine, and fossil-fuel-based AC generator along with different types of energy storage and conversion technologies such as battery and inverter. We then select six different regions of Korea to represent various characteristics of different RES potentials and demand profiles. We finally designed and analyzed the optimal RES stand-alone energy supply system in the selected regions using multiobjective optimization (MOOP) technique, which includes two objective functions: the minimum cost and the minimum $CO_2$ emission. In addition, we discussed the feasibility and expecting benefits of the systems by comparing to conventional systems of Korea. As a result, the region of the highest RES potential showed the possibility to remarkably reduce $CO_2$ emissions compared to the conventional system. Besides, the levelized cost of electricity (LCOE) of the RES-based energy system is identified to be slightly higher than conventional energy system: 0.35 and 0.46 $/kWh, respectively. However, the total life-cycle emission of $CO_2$ ($LCE_{CO2}$) can be reduced up to 470 g$CO_2$/kWh from 490 g$CO_2$/kWh of the conventional systems.

• Environmental and Resource Economics Review
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• v.16 no.4
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• pp.923-946
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• 2007

The goal of this study is to analyse the effects of financial support by governmental on KERRP (Korea Emission Reduction Registration Project) in the case of descending clock auction. Result shows that about 60% of total reduction (612,000ton) can be achieved at the price of 8,000 Won/ton with the budget amount of 5 billion Won, if the benefit from energy saving by the project is not included. Also 100% of total reduction (1,015,713ton) can be achieved at the price of 4,900Won/ton, if the benefit from energy saving by the project is included. Because most projects get some benefits from the energy saving occurred by project performance, the financial support by government may not be needed. However, this type of support would be meaningful from the aspect of encouraging GHG (Green House Gas) reduction to be prepared for the potential obligation of national GHG reduction from 2013.

• Resources Recycling
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• v.31 no.1
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• pp.56-64
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• 2022

Construction waste is generated at a rate of approximately 221,102 tons/day in Korea. In particular, mixed construction waste generates approximately 24,582 tons/day. The other components were recycled by 98.9%. The amount of greenhouse gas emissions from the waste was 17.1 million tons of CO2 equaling 2.3% of the total greenhouse gas emissions. To reduce greenhouse gas emissions, reducing the environmental impact is becoming increasingly important. However, appropriate treatment must first be established, as mixed construction waste is also increasing. Thus, an effective plan is urgently needed because it is frequently segregated and sorted by the landfill and incinerated. In addition, there is an urgent need to prepare various effective recycling methods rather than a simple treatment. Therefore, this study analyzed the environmental impact of the treatment of mixed construction waste by calculating greenhouse gas emissions. As a result, the highest greenhouse gas generation occurred during the incineration stage. Moreover, the optimal method to reduce greenhouse gas emissions is recycling and energy recovery from waste. In addition, the amount of greenhouse gas generated during energy recovery from the waste stage was the second highest. However, greenhouse gas emissions can be reduced by using waste as energy to reduce fossil fuel consumption. In addition, for the transportation stage, the optimal reduction plan is to minimize the amount of greenhouse gas emissions by setting the optimal distance and applying biofuel and electric vehicle operations.

• The Journal of the Convergence on Culture Technology
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• v.10 no.4
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• pp.693-700
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• 2024

As of the end of March 2022, the total area of domestic industrial complexes is 606 km2, which is only about 0.6% of the total land area. However, as of 2018, the annual energy consumption of domestic industrial complexes is 110,866.1 thousand TOE, accounting for 53.5% of the country's total energy consumption and 83.1% of the entire industrial sector energy consumption. In addition, industrial complexes have a significant impact on the environment, accounting for 45.1% of the country's total greenhouse gas emissions and 76.8% of industrial sector greenhouse gas emissions. Under this background, in this study, in order to contribute to the energy efficiency of industrial complexes, a prediction study on energy demand and supply for an industrial complex in Korea using machine learning was conducted. In addition, a simulator UI screen was designed to more efficiently convey information on energy demand/supply prediction results and energy consumption status. Among the machine learning algorithms, Multi-Layer Perceptron (MLP) was used, and Bayesian Optimization was applied as an optimization technique for the prediction model. The energy prediction model for the industrial complex built in this study showed a prediction accuracy of 87.90% for compressed air demand and 99.54% for the flow rate available for the public air compressor.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.42-42
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• 2020

충남서부권은 기상이변으로 강수량이 적고 가뭄이 심화되고 있는 반면, 신규수원 개발 적지 부족 등 용수공급에 어려움을 겪고 있다. 2015년부터 2016년까지 가뭄시 비상용수공급을 위해 비상도수로를 건설하였다. 이 비상도수로는 보령댐의 가뭄단계 상황기준으로 운영중에 있다. 가뭄단계 상황이 경계단계에 진입하면 도수로를 가동시작하여 관심단계 회복시에 중단하게 된다. 동 연구는 현재 운영중인 보령댐도수로의 가동Rule을 수량(이수안전도), 수질(BOD), 전력비용을 고려하여 시나리오별로(상시도수, 총 도수량대비 25%, 50%, 75%, 100%) 도수할 때 어느 도수 Rule이 수량-수질-에너지 넥서스 측면에서 가장 유리한지를 밝혀 내고자 하였다. 연구에 사용된 기초자료는 보령댐도수로 준공이후 2016년~2019년 도수실적 자료를 이용하였다. 수량(이수안전도) 검토는 MODSIM을 활용하였고, 수질개선효과는 실측 BOD를 기준으로 도수조건별로 오염부하량으로 검토하였다. 전력비용은 금강원수 도수년도별로 산정하여 분석하였다. 추가 연구결과를 통해 가뭄단계 상황기준, 월별 물관리 여건을 고려하여 기준향후 비상도수로 운영에 있어서 수량절량, 수질개선, 전력비용 절감을 기대할 수 있을 것이다.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.903-914
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• 2008

This study was undertaken for the production capacity expansion and energy saving through entire process simulation and optimization for the commercial process of manufacturing monoethylene glycol as a staple from ethylene oxide. Aspen $Plus^{TM}$(ver. 2006) was employed in the simulation and optimization work. The multicomponent vapor-liquid equilibria involved in the process were calculated using the NRTL-RK equation. As for the binary interaction parameters required for a total of 91 binary systems, those for 8 systems were self-supplied by the simulator, those for 28 systems were estimated through regression of the VLE data in the literature, and the remainder were estimated with the estimation system built in the simulator. Subsequent to ascertaining the accuracy of the generated parameters through comparison between actual and simulated process data, sensitive variables highly affecting the process were searched and selected using sensitivity analysis tool in the simulator. The optimum operating conditions minimizing the total heat duty of the process were investigated using the optimization tool based on the successive quadratic programming in the simulator.

• Korean Journal of Construction Engineering and Management
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• v.19 no.4
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• pp.52-60
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• 2018

In the construction industry, attempts to evaluate the environmental impact of products through life cycle assessment (LCA) approach has been on the rise. However, the domestic construction industry needs to make rapid decisions due to limited budget and schedule, so it is difficult to carry out a review of the environmental load on all resources. The decision-making process requires information on the major influence factors that should be focused on to reduce environmental load. And this information should be quantified so that it can be linked to environmental impact assessment. In this study, the LCA results of road construction cases were analyzed to provide such information. As a result, diesel, ready-mixed concrete, urethane-based paint, aggregate, and asphalt concrete were found to be the main factors that generated 93.17% of the environmental load in the earthwork type of road project. The total environmental cost caused by these affecting factors when constructing 1 km of earthwork type of road project is 242 million won. The analysis also shows that a 10% reduction in the amount of ready-mixed and asphalt concretes can reduce carbon emissions by 5.02% and 2.28% while reducing environmental costs by 11 million won per kilometer. In order to reduce carbon emissions of the earthwork type of road project, it is necessary to actively develop and introduce new methods and eco-friendly materials to reduce the overall use of ready-mixed concrete and asphalt concrete.

• Environmental and Resource Economics Review
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• v.31 no.2
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• pp.165-204
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• 2022

This study organized data from 2000 to 2014 for 20 grid-connected countries in Europe and analyzed the determinants of carbon emissions through the panel GLS method considering the problem of heteroscedasticity and autocorrelation. At the same time, the effect of introducing ETS was considered by dividing the sample period as of 2005 when the European emission trading system was introduced. Carbon emissions from individual countries were used as dependent variables, and proportion of generation by each source, power self-sufficiency ratio of neighboring countries, power production from resource-holding countries, concentration of power sources, total energy consumption per capita in the industrial sector, tax of electricity, net electricity export per capita, and size of national territory per capita. According to the estimation results, the proportion of nuclear power and renewable energy generation, concentration of power sources, and size of the national territory area per capita had a negative (-) effect on carbon emissions both before and after 2005. On the other hand, the proportion of coal power generation, the power supply and demand rate of neighboring countries, the power production of resource-holding countries, and the total energy consumption per capita in the industrial sector were found to have a positive (+) effect on carbon emissions. In addition, the proportion of gas generation had a negative (-) effect on carbon emissions, and tax of electricity were found to have a positive (+) effect. However, all of these were only significant before 2005. It was found that net electricity export per capita had a negative (-) effect on carbon emissions only after 2005. The results of this study suggest macroscopic strategies to reduce carbon emissions to green growth, suggesting mid- to long-term power mix optimization measures considering the electricity trade market and their role.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.271-277
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• 2021

In this study, experiments of local heating on crown and supplying warm nutrient for energy saving and improving growth of 'Seolhyang' strawberry were conducted. The temperature of inside and crown in greenhouses which were control (space heating 8℃) and test (space heating 5℃+crown heating) was measured. In the control greenhouse, the average of temperature and humidity in December was 7.1℃, 87.2%, respectively. In the test greenhouse, the average of temperature and humidity in December was 5.7℃, 88.7%. The temperature of crown and inside the bed were 7.9℃, 10.8℃ in control, 9.3℃, 12.7℃ in test. During the test period, the total 16,847×10³ kcal of energy was consumed in control greenhouse including space heating. In test greenhouse including space heating, crown heating and warm water supplying, total 9,475.7×10³ kcal of energy was consumed. So, energy consumption in test was 43.8% less than in the control. The total yields of strawberry during test period were 412.7g/plant for test greenhouse and 393.3g/plant for control greenhouse respectively.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.131-140
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• 2010

Zero waste clean city was visualized by designing the environmental fundamental facilities such as automated waste collection and bio-energizing system of domestic waste, which was categorized into food and combustible waste from urban area. The biomass circulation position was applied to the domestic waste collection position combined with bio-energizing system in the zero waste clean city. Bio-energizing system consisted of bio-gasification, bio-fuel and bioenergy-circulation process. Food wastes were treated by bio-gasification with anaerobic digestion, and combustible wastes were made of bio-fuel with pyrolysis/drying. Biogas and bio-fuel was utilized into the electric generation or boiler heat in bioenergy-circulation process. The emission of carbon dioxide(CO2) and construction fee of the environmental fundamental facilities related with domestic waste was estimated in the existing city and zero waste clean city, assuming the amount of food waste 35 ton/day, combustible waste 20 ton/day from domestic area. Consequently, 2.7 times lower carbon dioxide emission and 15% construction fee of the environmental fundamental facilities related with domestic waste were obtained from the zero waste clean city by comparing with existing city.