• KEPCO Journal on Electric Power and Energy
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• 제7권2호
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• pp.309-316
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• 2021

For the detection of the state of charge in VRFB-ESS, the analyses of UV-Visible spectrometry and the measurements of potential between the anolyte and catholyte were used in parallel. This paper includes the production of 4-valant ion from VOSO4 powder, 3- and 5-valant ions from electrochemical charge of 4-valant ion and 2-valant ion from 3-valant ion. It also includes the analyses of these valance ions and unknown electrolyte at any time using UV-Visible spectrometry. Through the analyses of the valance ions in samples, the SOCs of the samples at any charge-discharge times were verified.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.251-256
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• 2006

To design the effective usage of electric double layer capacitors (EDLCs) used for a storage device of dye sensitized solar cell (DSC) energy, we first investigated the accumulation state of electrical charges and the charge behavior in the EDLCs. Based on the results, the voltage characteristics of EDLCs connected to DSC energy were evaluated. The results showed that the charge accumulation region concentrated on the central part of the carbonaceous electrode in EDLCs and the required times for charging and discharging were almost the same.

• 조명전기설비학회논문지
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• 제21권4호
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• pp.28-35
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• 2007

In this paper, a study was made of the technology used to measure the remaining amount of energy in secondary cells, for which demand is ever increasing. First, the standard data were stored for measurement of the remaining energy and a compare/analysis algorithm was developed. Next, hardware was designed and a prototype that can display the SOC(State Of Charge) through an LCD displayinstrument was created. The small size of the prototype allows it to be portable and its performance is within ${\pm}4$[%].

• 대한화학회지
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• 제14권3호
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• pp.221-228
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• 1970

The tendency of forming a charge transfer complex between furfuryl derivatives (2-methyl furan, furfuryl acetate, and Ethyl 2-furoate) and halides(Iodine, Iodine monochloride, and Trichloro bromo methane) was studied by means of ultra violet spectrophotometry. In case of furfuryl acetate the formation of the complex could not be distinctly detected by this method. Iodine and trichloro bromo methane could show a distinct formation of charge transfer complex in the U.V. region, whereas iodine monochloride shows a possibility of forming an addition compound rather than the charge transfer complex itself. The results were discussed in conjunction with the stability of the furfuryl ring.

• 전기전자학회논문지
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• 제25권2호
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• pp.356-361
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• 2021

파워 소자의 트레이드오프 현상을 최소화하기 위해 제시된 구조가 Super Junction 구조이다. Super Junction은 기존의 많이 사용하던 기본 구조 대비 1/5 정도의 낮은 온 저항(Ron) 특성을 가질 수 있다. Super Junction 구조의 공정 방법으로 Multi-Epi 공정과 Deep-Trench 공정 방법이 있다. Deep-Trench 공정은 실리콘 기판 상면에 깊은 트렌치 공정을 통하여 그안에 불순물이 도핑 되어 있는 폴리실리콘을 매립하여 P-Pillar를 형성 시키는 공정 방법이라 매립하는 과정에서 결함이 형성되기 쉬워서 비교적 어려운 제조 방법으로 알려져 있다. 하지만 비교적 Deep-Trench 공정으로 만들어진 구조가 낮은 온저항과 높은 항복 전압을 형성하여 좋은 효율을 보인다. 본 논문에서는 공정상의 새로운 방법을 제시하고, Charge Balance 이론을 접목시킨 구조를 설계하였다.

• 한국산업융합학회 논문집
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• 제15권4호
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• pp.95-101
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• 2012

In order to explain observed catalytic reactivity of aminophosphine complexes (seven-membered chelate), total energy, net charge, atomic orbital electron population, HOMO and LUMO energy of free ligands are calculated by PM3 methods of HyperChem 6.0. Free ligands are 1,2-bis{(diphosphino)amino}propane{$H_2PNHCH_2CH(CH_3)NHPH_2$;ligand 1},1,2-bis{(dimenylphosphino)amino}propane{$(CH_3)_2PNHCH_2CH(CH_3)NHP(CH_3)_2$;ligand 2},1,2-bis{(diphenylphosphino)amino}propane{$(C_6H_5)_2PNHCH_2CH(CH_3)NHP(C_6H_5)_2$;ligand 3}. The result showed that ligand 3 is stable than ligand 2 and ligand 1 and ligand 2 is stable than ligand 1 in total energy. Net charge of P atom is changed by H atom, methyl groups and phenyl groups in P atoms. Net charge of N atoms in ligands is nagative. The results of atomic orbital electron population are similar net charge data..

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1369-1375
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• 2017

This paper presents an optimal operation scheduling algorithm for a smart home with energy storage system, electric vehicle and distributed generation. The proposed algorithm provides the optimal charge and discharge schedule of the EV and the ESS. In minimizing the electricity costs of the smart home, it considers not only the cost of energy purchase from the grid but also the life cost of batteries. The life costs of batteries are calculated based on the relation between the depth of discharge and life time of battery. As the life time of battery depends on the charge and discharge pattern, optimal charge and discharge schedule should consider the life cost of batteries especially when there is more than one battery with different technical characteristics. The proposed algorithm can also be used for optimal selection of size and type of battery for a smart home.

• Environmental Engineering Research
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• 제23권4호
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• pp.383-389
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• 2018

Microbial fuel cell (MFC) is an innovative environmental and energy system that converts organic wastewater into electrical energy. For practical implementation of MFC as a wastewater treatment process, a number of limitations need to be overcome. Improving cathodic performance is one of major challenges, and introduction of a current collector can be an easy and practical solution. In this study, three types of current collectors made of stainless steel (SS) were tested in a single-chamber cubic MFC. The three current collectors had different contact areas to the cathode (P $1.0cm^2$; PC $4.3cm^2$; PM $6.5cm^2$) and increasing the contacting area enhanced the power and current generations and coulombic and energy recoveries by mainly decreasing cathodic charge transfer impedance. Application of the SS mesh to the cathode (PM) improved maximum power density, optimum current density and maximum current density by 8.8%, 3.6% and 6.7%, respectively, comparing with P of no SS mesh. The SS mesh decreased cathodic polarization resistance by up to 16%, and cathodic charge transfer impedance by up to 39%, possibly because the SS mesh enhanced electron transport and oxygen reduction reaction. However, application of the SS mesh had little effect on ohmic impedance.

• Korean Chemical Engineering Research
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• 제45권3호
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• pp.242-248
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• 2007

자동차 전기장치 시스템을 최적화하기 위해서는 차량용 납축전지의 충전 및 방전 거동을 예측할 수 있는 모델링 기술이 필요하다. 본 연구에서는 유한요소법을 이용하여 차량용 12-V 납축전지의 충전 및 방전 거동을 예측할 수 있는 2차원 모델링을 수행하였다. 이 연구에 사용된 수학적 모델에는 전기화학반응 속도론, 전해질의 유동, 대류에 의한 이온의 전달현상, 전극의 시간에 따른 공극률의 변화 등이 고려되었다. 모델링의 신뢰성을 검증하기 위하여 방전 및 충전실험을 수행하였다. 방전실험은 $25^{\circ}C$에서 C/5, C/10 및 C/20의 방전율에 대하여 수행하였고, 충전실험은 $25^{\circ}C$에서 정전류-정전압 방법으로(제한전류 30A, 제한전압 14.24 V) 수행하였다. 모델에 근거하여 예측된 충 방전 거동은 충 방전 실험결과와 잘 일치하였다. 또한 2차원 모델링을 통하여 충 방전이 진행되는 동안 실제로 측정이 불가능한 납축전지 내부의 전류밀도, 전해액의 농도 및 충전상태(state of charge; SOC)의 분포를 예측할 수 있었다.

• 설비공학논문집
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• 제12권5호
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• pp.486-493
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• 2000

A theoretical model for the transient performance of vapor-compression air-conditioning system has been developed to evaluate the influence of the refrigerant charge on the system performance. A set of mass and energy equations for the simulation of the heat exchangers and the capillary tube and a polytropic compression model for the compressor are used. The present model successfully predicts the transient behavior of the vapor-compression air-conditioner from the startup. As the refrigerant charge is increased, both the evaporating and condensing pressures increase gradually, and the cooling rate and the COP show a maximum in the range of 0.75-0.8 kg of refrigerant charge. This amount of refrigerant mass is determined to be the optimum charge of the model system. Also, the effect of outdoor air temperature on the optimum refrigerant charge is discussed.