• 조명전기설비학회논문지
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• 제29권4호
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• pp.85-94
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• 2015

Recently, research on the smart grid that combines ICT(Information & Communication technology) to the power system has been actively progressed. If the occupancy of the EV(Electric vehicle) is increased. the V2G(Vehicle to grid) system is available which constitutes the micro-grid through battery of EV. V2G system performs load leveling and efficient energy consumption by battery operation considering load condition. But, if the battery is used only depending on the electricity rates, it doses not consider the life of the battery. The ACC(Achievable cycle) and the total transferable energy of battery varies corresponding to the selected DOD(Depth of discharge). In this paper, the optimal DOD selection method of V2G system considering battery wear cost and average driving distance of EV. Also, the total revenue prediction of various nation is presented considering the actual electricity costs per hour.

• 에너지공학
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• 제8권2호
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• pp.265-271
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• 1999

최근 우리나라는 전력산업의 효율성 향상과 경쟁체제 강화를 위하여 발전시장을 민간에 개방하고, 경쟁입찰에 의해 민전 사업자의 진입을 확대하고 있다. 이러한 민전 사업에 있어서 향후 전력요금의 지불패턴은 매우 중요하다. 현재는 용량요금에는 균등화 지불패턴을 그리고 전력량 요금에는 물가상승률을 반영하고 있다. 본 논문은 일반전기사업자와 발전사업자간의 전력거래시 발생하는 연도별 요금수준을 각종 지불패턴에 따라 산정하는 방법을 제시하고, 그 결과를 비교 분석하였다. 분석 결과, 양사간의 위험도를 분산할 수 있는 부분 하향식 지불패턴이 우리나라 전력시장에서 적용가능성이 크고, 할인율의 요금에 대한 영향이 큰 것으로 나타났다.

• 에너지공학
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• 제7권2호
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• pp.223-230
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• 1998

서울특별시 소재 대형 상업건물중 50개 에너지 다소비업체를 선정하여 에너지 사용실태를 조사하였다. 조사대상 건물은 병원, 호텔, 백화점/사무실 등 3개 집단으로 분류하여 시설현황, 에너지사용량, 부하분포특성 등을 분석하였다. 여름철 냉방전력 사용량이 열부하 피크 발생에 직접적인 영향을 미치는 것으로 나타났으며 이를 열병합발전-흡수식 냉동기 방식으로 대체할 경우 전기부하 분포가 연간 비교적 일정하게 변환시킬 수 있어 열부하추종운전방식에 적합함을 알 수 있었다. 그러나, 단일건물의 경우 연간열부하분포가 경제적 규모에 미달하여 단독으로 열병합발전 설비를 도입하기에는 미흡한 점이 있어 다수건물을 대상으로 하는 공동 열병합발전 방식이 보다 유리한 것으로 판단된다. 이를 추진하기에는 전기사업법, 액화천연가스 요금체계 등과 같은 법제도의 정비가 선결되어야 할 것이다.

• 수산해양기술연구
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• 제52권1호
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• pp.65-71
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• 2016

Injection rate, injection quantity and injection timing of fuel are controlled precisely by electric control in CRDI system. Particularly, injection rate being influenced with injection pressure affects to spray characteristics and fuel-air ratio, so it is a very important factor in diesel combustion. In this study, injection rates in accordance with injection pressure at a constant ambient pressure were measured with Zeuch's method. Under the same condition, non-evaporating spray images were taken with a high speed camera and analyzed carefully with Adobe Photoshop CS3. Macroscopic spray characteristics and breakup processes in the spray could be found from the examined and analyzed data. Injection start time and injection period were practically affected with injection pressure. Also, initial injection rate, spray penetration, spray angle and breakup of high density droplets region in the spray were affected with injection pressure. The results and techniques of spray visualization and injection rate measurement in this study would be practically effective to study a high pressure diesel spray for common rail direct injection system.

• 조명전기설비학회논문지
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• 제27권9호
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• pp.44-52
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• 2013

This paper presents the development of 10 kW permanent magnet synchronous generator (PMSG) for small hydropower plants considering flow rates and net head. The initial and detailed design are determined using a load distribution method (LDM) which is a well-known method for designing an electric machine and a 2D-FEA which is performed for more accurate analysis of PMSG. The characteristic analysis results of proposed model with straight line magnet are satisfied with the initial model with curved magnet. Finally, the analysis and the design results are confirmed by the experimental results.

• 한국수소및신에너지학회논문집
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• 제26권2호
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• pp.96-104
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• 2015

Reactivity of commercial WGS catalyst and four new catalysts(RMC-3, PC-73, PC-67SU, PC-59) manufactured with various compositions by Korea Electric Power Research Institute(KEPCO RI) were compared to select suitable WGS catalyst for SEWGS system. Steam/CO ratio, gas velocity, flow rates of syngas, and temperature were considered as operating variables. As a result, commercial catalyst showed the highest CO conversion and RMC-3 catalyst showed also high CO conversion. Therefore, commercial and RMC-3 catalysts were selected as applicable catalysts. However, PC-73 catalyst showed low CO conversion at low temperature($200^{\circ}C$) but showed good reactivity at high temperature($225{\sim}250^{\circ}C$), and therefore, PC-73 catalyst was selected as applicable catalyst for high temperature operation. Continuous operations up to 24 hours for those three catalysts(commercial, RMC-3, PC-73) were conducted to check reactivity decay of catalysts. All three catalysts maintained their original reactivity.

• 한국산학기술학회논문지
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• 제17권7호
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• pp.54-62
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• 2016

열을 전기로 바꾸는 장치로 가장 효율이 우수한 장치인 AMTEC은 알칼리금속을 작동유체로 하여 열을 직접적으로 전기로 변환시키는 장치이다. AMTEC은 저압용기, 고압용기, 베타 알루미나 고체 전해질, 그리고 순환윅으로 이루어져있다. AMTEC에서의 열손실은 주요하게 저압용기에서의 BASE와 응축부 사이에서 발생하는 열복사손실이며, 암텍의 발전량은 BASE의 온도유지력에 영향을 받기에 BASE의 표면온도를 고온으로 유지시켜주어야 고효율 발전량은 일정하게 유지할 수 있다. 이를 위하여 저압챔버에서의 복사 열손실을 줄이고 BASE온도는 상승시키고, AMTEC 시스템의 발전량 향상을 위하여 저압용기 내부의 6가지 형태의 열복사차단막에 따른 출력을 전산유체해석을 통하여 분석하였다. 분석에서 최적의 열복사차단막 형상은 수직부에 곡률을 가질 때이며, 그 때의 온도에 대한 무차원수(응축부온도/BASE온도 비)는 0.665 정도이고 출력은 약 17.69 W 정도로 다른 형상에 대비하여 높은 발전량을 갖는 것으로 계산되었다. 높이에 따른 발전량의 차이에서는 수평차단막이 BASE 상부로부터 멀리 떨어진 경우 발전량이 가장 우수하며, 17.58W 정도로 나타났다. 여러 개의 작은 홀과 다중 수평차단막을 설계한 경우는 기준이 되는 형상보다 오히려 발전량이 감소하였으며, 각각 0.91W, 2.06W 정도 감소하였다.

• Asian Journal of Atmospheric Environment
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• 제8권1호
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• pp.25-34
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• 2014

In winter 2013, extreme air pollution by fine particulate matter ($PM_{2.5}$) in China attracted much public attention. In order to simulate the $PM_{2.5}$ pollution, the Community Multiscale Air Quality model driven by the Weather Research and Forecasting model was applied to East Asia in a period from 1 January 2013 to 5 February 2013. The model generally reproduced $PM_{2.5}$ concentration in China with emission data in the year 2006. Therefore, the extreme $PM_{2.5}$ pollution seems to be mainly attributed to meteorological (weak wind and stable) conditions rather than emission increases in the past several years. The model well simulated temporal and spatial variations in $PM_{2.5}$ concentrations in Japan as well as China, indicating that the model well captured characteristics of the $PM_{2.5}$ pollutions in both areas on the windward and leeward sides in East Asia in the study period. In addition, contribution rates of four anthropogenic emission sectors (power generation, industrial, residential and transportation) in China to $PM_{2.5}$ concentration were estimated by conducting zero-out emission sensitivity runs. Among the four sectors, the residential sector had the highest contribution to $PM_{2.5}$ concentration. Therefore, the extreme $PM_{2.5}$ pollution may be also attributed to large emissions from combustion for heating in cold regions in China.

• 한국연소학회지
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• 제20권1호
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• pp.6-14
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• 2015

Numerical study was conducted to clarify effects of added $H_2O$ for the downstream interaction between $H_2$-air and CO-air premixed flames in counterflow configuration. The reaction mechanism adopted was Davis model which had been known to be well in agreement with reliable experimental data. The results showed that both lean and rich flammable limits were reduced in increase of strain rate. The most discernible difference between the two with and without having $H_2O$ and/or $H_2$ addition into $H_2$-air and CO-air premixtures was two flammable islands for the former and one island for the latter at high strain flame conditions. Even a small amount of $H_2$, in which $H_2$-air premixed flame cannot be sustained by itself, participates in CO oxidation, thereby altering the CO-oxidation reaction path from the main reaction route $CO+O_2{\rightarrow}CO_2+O$ with a very long chemical time in CO-air flame to the OH-related reaction routes including $CO+OH{\rightarrow}CO_2+H$ with very short chemical times. This intrinsic nature alters flame stability maps appreciably. The results also showed that chemical effects of added $H_2O$ help lean flames at relatively low strain rate be sustained, and suppress the flame stabilization at high strain rates.

• 한국물환경학회지
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• 제31권5호
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• pp.556-562
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• 2015

In order to remove the organic substances and the nitrate-nitrogen contained in wastewater, some researchers have studied the simultaneous removal of organics and nitrogen by using different biocathode microbial fuel cells (MFCs). The operating conditions for removing the contaminants in the MFCs are the external resistances, HRTs, the concentration of the influent wastewater, and other factors. This study aimed to determine the effect of the external resistors and organic loading rates, from the changing HRT, on the removal of the organics and nitrogen and on the production of electric power using the Denitrification Biocathode - Microbial Fuel Cell (DNB-MFC). As regards the results of the study, the removal efficiencies of $SCOD_{Cr}$ did not show any difference, but the nitrate-nitrogen removal efficiencies were increased by decreasing the external resistance. The maximum denitrification rate achieved was $129.2{\pm}13.54g\;NO_3{^-}-N/m^3/d$ in the external resistance $1{\Omega}$, and the maximum power density was $3,279mW/m^3$ in $10{\Omega}$. When the DNB-MFC was operated with increasing influent organic and nitrate loading by reducing the HRTs, the $NO_3{^-}-N$ removal efficiencies were increased linearly, and the maximum nitrate removal rate was $1,586g\;NO^3{^-}-N/m^3/d$ at HRT 0.6 h.