• Clean Technology
• /
• v.17 no.4
• /
• pp.406-411
• /
• 2011

A detailed database of waste heat is built to propose energy exchange networks to recover waste energy in Pohang Steel Industrial Complex. A visualized technique is used to figure out the status of waste heat energy and to suggest potential energy exchange networks. Several energy networks are proposed in terms of temperature level, the amount of available energy, distance, and construction cost. A simple economical assessment is applied to the energy exchange networks which have higher economic potential. Their average payback period is estimated to be 2.8 years. The total amount of energy saving by constructing the proposed energy exchange networks is 4,778 TOE per year. It corresponds to 11,160 ton $CO_2$ reduction with the assumption that the recycled waste energy replaces the use of LNG in energy-demanding companies.

• Journal of the Korean Electrochemical Society
• /
• v.17 no.3
• /
• pp.139-148
• /
• 2014

Electrochemical energy-storage devices such as batteries and supercapacitors are important components in emerging portable electronic device, electric vehicle, and clean energy storage and supply technologies. This review describes recent progress in the development of nanostructured electrodes, the main component of the electrochemical energy-storage device, prepared by layer-by-layer (LbL) electrostatic assembly. Major advantages associated with, and challenges to, the fabrication of LbL electrodes, as well as the future outlook for expanding the application of LbL techniques, are discussed.

• Korean Chemical Engineering Research
• /
• v.48 no.1
• /
• pp.1-9
• /
• 2010

Since carbon dioxide, $CO_2$, was revealed as a major greenhouse gas, techniques for its separation, capture, and storage have received increasing interest in recent years. Aqueous amines are the most widely accepted $CO_2$ absorbents, but they cause the problems such as high regeneration energy, thermal degradation, and loss of absorbents due to their volatility. Ionic liquids having high thermal stability, extremely low vapor pressure, and capability of selectively absorbing specific gases have been proposed as new $CO_2$ capturing solvents which may potentially replace aqueous amines. By reviewing the ionic liquids having capability to absorb $CO_2$ reported in previous papers, we seek to develop a comprehensive understanding on the factors that influence the $CO_2$ solubility in ionic liquids such as their structures, absorption temperature, pressure, water content, etc., and to estimate the potential of ionic liquids as $CO_2$ separating media.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 1993.05a
• /
• pp.42-46
• /
• 1993

1970년대의 오일쇼크이후 대체에너지개발의 중요성에 대한 인식이 점차 확산되어 가는 추세에 있다. 대체에너지가운데 특히 태양광발전은 연료가 필요 없는 무공해 Clean 에너지원으로서 미래 전원공급원의 한 부분으로 그 역할이 주목되고 있다. 더욱이 자원이 빈약한 국내실정 하에서 태양광발전의 기술개발은 필연적이므로 향후 보급촉진을 위한 실용화방안을 제시하고자 한다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2001.05a
• /
• pp.27-32
• /
• 2001

• Solar Energy
• /
• v.18 no.2
• /
• pp.19-29
• /
• 1998

Solar energy is a quantitatively unlimited, clean and non-pollutant source. It has a great potential for industrial commercial usages. For example, solar hot water system for domestic usage has been very popular in many counties. In Korea, the industries consume 47.7% of the total national energy, and the manufacturing sector uses 91.5% out of it. The main energy resoures available in Korea are oils, coals, and gases. There have been continuous efforts among the industries to reduce such energy consumptions by using alternative energy resources, such as solar energy, yet the technology has limited its proper applications to a level of satisfaction. In some advanced countries, research and development programs in solar energy applicable to the industrial usages are very active, and some systems are in the commercial market. Therefore, this paper describes the status and the feasibility for high-efficiency evacuated solar collector which was anticipated to applied for industrial process heat as an alternative of fossil energy.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.420-421
• /
• 2006

The cost-effective reduction of greenhouse gas(GHG) emission to avert the most severe impacts of climate change remains one of the widely accepted priorities for global action. In order to facilitate cost-effective abatement strategies, the Kyoto Protocol introduced three mechanisms, or flexible instruments, the Emissions Trading(ET), the Joint Implementation(JI) and the Clean Development Mechanism(CDM). The CDM enables Annex I countries to the Kyoto Protocol to partially meet cost-effectively their emission reduction commitments by undertaking GHG mitigation Projects in developing countries, which do not have any GHG abatement obligations and where the emission reductions are cheaper. One of the major barriers hampering the wide spread implementation of CDM is the high transaction costs associated with the initial identification of promising CDM projects. This paper presents development of a pre-validation program of CDM. The developed program may provide a useful aid to potential investors and project developers as a supportive pre-evaluation tool, and may become an effective tool for the promotion of renewable energy and fuel switching projects.

• Journal of Hydrogen and New Energy
• /
• v.21 no.5
• /
• pp.412-418
• /
• 2010

Steam reforming of n-hexadecane, a major component of diesel over Ni-based hydrotalcite-like catalyst was carried out at $900^{\circ}C$ at atmospheric pressure with space velocity of $10,000h^{-1}$ and feed molar ratio of steam/carbon=3.0. Ni-based hydrotalcite catalyst was prepared by a solid phase crystallization (spc) method and characterized by $N_2$-physisorption, CO chemisorption, TPR., XRD, and TEM techniques. It was found that spc Ni/MgAl catalyst showed higher catalytic stability and inhibition of carbon formation than Ni/$\gamma-Al_2O_3$ catalyst under the tested conditions. The results suggest that the modified spc-Ni/MgAl catalyst after optimization may be applied for the SR reaction of diesel.

• Korean Chemical Engineering Research
• /
• v.45 no.3
• /
• pp.264-268
• /
• 2007

The filtration performance of micron-sized metal fibrous filter was improved by synthesizing carbon nanotubes grown on the surface of metal fibers. The carbon nanotubes are grown with bush-like nanostructures covered around the micron-fibers or web-like nanostructures crossing between the fibers at different synthetic conditions. Filtration efficiency of CNT-metal-filter was measured and compared with the efficiency of the raw metal filter without CNTs. The developed CNT-metal-filter has higher filtration efficiency without significant difference in pressure drop compared with the conventional metal filter, which is because the carbon nanotubes function as the trap of pollutant nanoparticles.

• Clean Technology
• /
• v.28 no.2
• /
• pp.138-146
• /
• 2022

Electricity has become a factor that dramatically affects the market economy. The day-ahead system marginal price determines electricity prices, and system marginal price forecasting is critical in maintaining energy management systems. There have been several studies using mathematics and machine learning models to forecast the system marginal price, but few studies have been conducted to develop, compare, and analyze various machine learning and deep learning models based on a data-driven framework. Therefore, in this study, different machine learning algorithms (i.e., autoregressive-based models such as the autoregressive integrated moving average model) and deep learning networks (i.e., recurrent neural network-based models such as the long short-term memory and gated recurrent unit model) are considered and integrated evaluation metrics including a forecasting test and information criteria are proposed to discern the optimal forecasting model. A case study of South Korea using long-term time-series system marginal price data from 2016 to 2021 was applied to the developed framework. The results of the study indicate that the autoregressive integrated moving average model (R-squared score: 0.97) and the gated recurrent unit model (R-squared score: 0.94) are appropriate for system marginal price forecasting. This study is expected to contribute significantly to energy management systems and the suggested framework can be explicitly applied for renewable energy networks.