• Journal of Energy Engineering
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• v.2 no.1
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• pp.123-132
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• 1993

This work is focussed on the reduction of ethanol separation energy from alcohol fermented broth and categorized into the development of a computer program for the design of the pressurized/depressurized distillation process which has been regarded as one of the energy-reducing models for the conventional distillation process, the optimization of operating conditions of distillation towers by means of the developed program, and the evaluation of the total annual energy cost of pressurized/depressurized distillation columns compared with that of the conventional single distillation columns. The operating pressures are, in case of pressurized/depressurized distillation, 3103/760 mmHg, 3103/450 mmHg, 3103/160 mmHg, and in case of conventional distillation, 760 mmHg. The optimum reflex rations which the sum of the annual energy cost and the annual fixed cost for each process becomes minimum are 3.7475/2.9111 for the operating pressures of 3103/760 mmHg, 3.814/2.9712 for 3103/450 mmHg, 3.0783/2.2400 for 3103/150 mmHg, and 3.8544 for the atmospheric operating pressure. And the annual energy cost of pressurized/depressurized distillation process for the above-mentioned operating pressures is distributed between 42% and 47% of that of conventional distillation process.

• Clean Technology
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• v.16 no.3
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• pp.213-219
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• 2010

Vortex tube is the device that can separate small particles from the compressed gas, as well as compressed gas into hot and cold gas. Due to energy and particle separation ability, a vortex tube can be used as the main component of the $CO_2$ absorption device. In this study, experimental approach has been performed to analyze the energy separation characteristics of the vortex tube. To obtain the preliminary design data, energy separation characteristics of the vortex tube has been tested for orifice diameter, nozzle area ratio, and tube length. As a result, the orifice diameter is the major factor of the vortex tube design. The nozzle area ratio and tube length have a minor effect on the energy separation performance. For Dc=0.6D, AR=0.14~0.16, and L=16D, maximum energy separation has been occurred. The result from this study can be used as the basic design data of the $100Nm^3$/hr class vortex tube applied to the $CO_2$ absorption device. Compared with the $CO_2$ absorption process containing an absorption tower, the process with a vortex tube is expected to have a huge advantage of saving the installation space and the operating cost.

• Korean Journal of Construction Engineering and Management
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• v.18 no.1
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• pp.27-36
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• 2017

Ministry of Land, Infrastructure and Transport established Heating and cooling energy conservation plan of apartment for 2017, reducing 90% compared to energy consumption of 1990. Also, at 2015 United Nations Climate Change Conference, the Ministry announced to reduce 37% of estimated $CO^2$ emission(850 million ton) at 2030. To satisfy this, it is urgent to reduce $CO^2$ emission due to the building, which takes majority amount of total $CO^2$ emission, and public interest for the commissioning of intensified building performance is uprising. However, the building commissioning at construction is not enacted, and not activated due to the lackness of promotion and will of general contractor. Furthermore, commissioning is not mandatory for obtaining G-SEED certification. Therefore, this paper describes effectiveness of commissioning with comparison of commissioning evaluation criteria of G-SEED with LEED and BREEAM, to propose making commissioning as mandatory process and drive changes in perception among stakeholders for activation of domestic building commissioning.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.291-294
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• 2007

Countries in the world are setting up policies to implement anti-global warning measures to actively cope with the Agreement on Climate Change. Rising problems related to energy and environment prompted research and development efforts to highly efficient electric instrument and environmentally friendly products to secure resources and save energy Korea's high dependency on imported energy and its lack in natural resources make it urgently necessary to develop energy efficient instrument and equipment that can save energy. Every household now uses a transformer, which is very important instrument among others. A variety of technologies to manufacture transformers are currently used along with efforts to develop new materials. Development nit of high efficient transformers is called for by the time and has direct economic impact on suppliers and consumers. In addition, it is desirable to install a transformer that is trustworthy, secure, low on loss, anti-incident capable, small, anti-flammable, environmentally friendly, cost-efficient high-frequency resistant and easy for maintenance. To do this, it is necessary to look deeper into a highly efficient transformer that can save energy. This paper will discuss the types and characteristics of various transformers and propose ways to save energy and raise efficiency tv analyzing a environmentally friendly amorphous transformer.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2112-2113
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• 2011

우리나라는 연평균 강수량이 1,245mm로써, 비교적 강수량이 풍부하고 전국토의 2/3가 산지로 구성되어 있어 지형적 및 수문학적으로 수력자원 부존량이 많은 편이다. 하지만 수력자원 활용을 통한 발전소 건설은 매우 미미한데 이는 수력발전소 개발지점이 제약되어 있고 개발지점의 가동율 또한 매우 낮아 경제성 확보가 어렵기 때문이다. 수력발전은 전력수요 급증 시 부하 평준화 효과와 석유 수입대체 및 환경 친화적인 에너지원이라는 장점이 있다. 따라서 국산화된 수차발전시스템의 사용으로 초기투자비를 낮추고 하천형 수력발전소 건설을 통하여 가동율을 높인다면 우리나라의 수력발전사업은 크게 활성화 될 것이다. 본 논문에서는 하천형 수력발전소 시공사례를 통하여 주요 시공사례를 소개하고, 하천공사의 특징으로 인하여 설계 및 시공 시 반영해야 할 사항에 대해 몇 가지 소개하였다. 표준화를 통하여 건설비용을 절감, 발전 단가의 기준가격 현실화를 통한 재정적인 지원 및 법규 정비를 통한 제도적인 도움 이 세가지를 해결한다면 경쟁력 있는 소수력발전소 건설이 가능 할 것이다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1199-1205
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• 2014

A power system configuration has been increasingly advanced with a number of generating units. In particular, renewable energy resources are widely introduced due to the environmental issues. When applying the renewable energy sources with the ESS (Energy Storage System), the ESS is the role of a potential generating resource in the power system while mitigating the output volatility of renewable energy resources. Thus, for applications of the ESS, the surrounding environment of it should be considered, which means that capacity and energy of the ESS can be affected. Moreover, operation strategy of the ESS should be proposed according to the installation purpose as well as the surrounding environment. In the paper, operation strategy of the ESS is proposed considering load demand and the output of renewable energy resources on a hourly basis. Then, the cost of electrical energy is minimized based on the economic model that consists of capital cost, operation cost, fuel cost, and grid cost for a year. It is sure that peak-shaving effects can be achieved while satisfying the minimum cost of electrical energy.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.1-8
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• 2010

Recently, the demand of landscape lighting for underwater dam is rapidly increased by expansion of hydrophilic space. But it occurred the problems such as weakness of safety and display effect of underwater dam lighting lamp currently in use. Therefore, for solving these problems and improving underwater dam lighting lamp, this paper is focused on safety, energy saving, display flexibility of underwater dam lighting lamp and analyzed the related deriving problems by research on the actual condition. As a result, it presents a developed LED mold type underwater light instead of underwater dam lighting lamp. By the results of this research, it is considered that practical use of underwater dam lighting is very useful in waterside space for dams, water fountain, swimming pool, and etc. Moreover, it can be extended/applied in various ways.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1275-1278
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• 2012

Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of electroconductive ceramic composites. Temperature rising time of sheath heater is 1.1 times faster than SiC ceramic heater. Heating insulation of SiC ceramic heater is 2.7 times larger than sheath heater. If SiC ceramic heater is one body type of a product application, contact resistance will decrease. I think that temperature initial rising time is faster than now. The more SiC ceramic heater is used for a long time, the more economic benefit is larger in the view point of heat insulation.

• Membrane Journal
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• v.1 no.1
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• pp.78-95
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• 1991

Water factory 21(WF 2) in Orange County California, is a advanced wastewater treatment(AWT) plant designed to reclaim biologically treated munidpal wastewater for injection into a seawater barrier system. Processes included are lime treatment air stripping, filtration, activated carbon adsorption, reverse osmosis(RO), and chlorination. The effectiveness of each treatment process is presented including pretreatment, RO dimineralization. The data collected show that the processes, including RO, used at WF-21 are capable of producing a very high quality water on a reliable basis. Treatment reduced all contaminants, to levels below national primary drinldng water regulation maximum contaminant levels. It was found that lime clarified secondary effluent can be used as feedwater to a RO dimineralizer. Experiments with new low pressure membrane(250psi) show great potential for reducing RO cost.

• Electronics and Telecommunications Trends
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• v.29 no.6
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• pp.53-62
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• 2014

본고는 최근 화두가 되고 있는 에너지 절감을 위해 고효율, 친환경의 WBG(Wide Band-Gap) 화합물반도체인 SiC(Silicon Carbide), GaN(Gallium Nitride) 전력반도체 소자 및 전력변환 모듈의 기술동향과 ETRI에서 연구개발 진행 중인 GaN 전력반도체 관련 기술에 대해 기술한다. WBG 전력반도체는 기존의 실리콘 전력반도체와 비교하여 열 특성 향상, 고속 스위칭, 고전압/고전류 특성 및 스위칭 손실 최소화 등이 가능하고 이에 따른 시스템의 소형화 및 전력효율 향상 효과를 얻을 수 있다. 특히, GaN 전력반도체 소자는 시장이 가장 넓게 형성되어 있는 900V 이하에 적용이 가능하며, 앞으로 시장이 커질 것으로 예상되는 HEV(Hybrid Electric Vehicle)/EV(Electric Vehicle)의 친환경 자동차에도 활용될 것으로 기대되고 있다. 본고는 최근의 일본과 미국에서의 WBG 전력반도체에 대한 관심 및 투자 방향과 GaN 전력반도체 소자에 대한 해외 기업의 업계동향에 대해서도 함께 살펴본다. 이러한 WBG 전력반도체에 대한 해외 선진업체의 산업동향과 더불어 ETRI에서 연구개발 중인 GaN 전력반도체 기술현황에 대해 전력소자 설계 및 제조공정, 패키징, 전력모듈 설계 제작 기술을 포함하여 기술한다.