• Title, Summary, Keyword: Expected efficiency

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A Study on the Optimal Operation According to Appropriate PCS and Battery Capacity Estimation of PV-BESS System (PV-BESS 시스템의 적정 PCS, 배터리용량 산정에 따른 최적 운영에 관한 연구)

  • Choi, Yun Suk;Na, Seung You
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.9
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    • pp.1174-1180
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    • 2018
  • In December 2017, the government announced plans to increase the current proportion of renewable energy from 7% to 20% by 2030 through a plan called the Renewable Energy 3020 Implementation Plan. Therefore, the demand for installation of photovoltaic(PV), wind turbine(WT) and battery energy storage system(BESS) is expected to increase. In particular, the system combined with energy storage system(ESS) is expected to take up a large portion since PV and WT can receive high renewable energy certificates(REC) weights when combined with ESS. In this study, we calculate the optimal capacity of the power conditioning system(PCS) and the BESS by comparing the economical efficiency and maximize the efficiency of the PV-BESS system in which the PV and the BESS are connected. By analyzing the system marginal price(SMP) and REC, it maximize profits through application of REC weight 5.0 and optimal charge-discharge scheduling according to the SMP changes.

Modelling and Analysis of AFPM, RFPM Compound Generator (AFPM, RFPM 복합발전기의 모델링 및 해석)

  • Kim, Jin-Sa
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.7
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    • pp.459-462
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    • 2017
  • In this study, we design, model, and analyze a compound generator that combines the axial flux permanent magnet (AFPM,) and radial flux permanent magnet (RFPM), which is expected to increase power generation by allowing the magnets to be placed on the upper, lower, left, and right sides of the same-sized generator. Through the design, modelling, and analysis of AFPM and RFPM compound generators, the generator load evaluation results rated output of 500.25 W and efficiency of 87.60%, respectively, at a rated speed of 600 rpm. By employing this complex generation system,these findings are expected to contribute to the activation of a small power generation system.

EFFICIENCY MEASUREMENT AND ENERGY ANALYSIS FOR A HEV BENCH TESTER AND DEVELOPMENT OF PERFORMANCE SIMULATOR

  • OH K.;KIM D.;KIM T.;KIM C.;KIM H.
    • International Journal of Automotive Technology
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    • v.6 no.5
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    • pp.537-544
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    • 2005
  • This paper presents the efficiency measurement and energy analysis for a parallel HEY. Using the HEV test rig, the efficiency of each powertrain component is measured for a given driving cycle including the regenerative braking system. Accompanied by the efficiency measurements, a detailed energy analysis is performed. Based on the efficiency measurement and energy analysis, a HEV performance simulator is developed. Using the simulator, the HEV performance is evaluated for a mild hybrid system. It is expected that the HEV simulator developed can be used to obtain further optimization potentials.

High Efficiency Tracking Drive in DC Motor by Field Winding Switching Method (계자권선 절환에 의한 직류전동기의 고효율 추종 운전)

  • Yoon, Ki-Jeong;Kim, Kwang-Heon
    • Proceedings of the KIEE Conference
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    • pp.493-496
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    • 1997
  • This paper constructed the experimental system which is able to drive in series or separately excited by switching of the field winding, using a DC motor and obtained the characteristics of efficiency with speed and torque of each motor's type through the experiment. From this result controlled drive which is able to series DCM or separately excited DCM in the optimal point of efficiency as finding the types of motor having maximum efficiency with torque and speed. By performing high efficiency tracking drive, it is expected that energy consumption of power source with limited energy density would be reduced, and so utility efficiency would be improved.

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A Study by Proposal of Efficiency Increase for a Full-scale Wastewater Reclamation Facility using a Biofilter Packed with Granular Sulfur (하수처리수 재이용을 위한 실규모 입상황 생물막여과 시설의 효율증대 방안에 관한 연구)

  • Moon, Jin-Young;Hwang, Yong-Woo;Baek, Seung-Ryun
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.1
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    • pp.73-83
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    • 2010
  • This study was performed to increase the removal efficiency of the biofilter packed with granular sulfur in municipal wastewater reclamation facility. Constituent units were influent water tank, denitrification tank, BOD reduction tank and outlet. And, the major operation factor is a biofilter packed with submerged granular sulfur. Actual wastewater and synthetic wastewater were used as influent wastewater. Experimental condition was divided into two phases according to the amount of a phosphorus coagulant. Total phosphorus removal efficiency was insignificant at mode I that phosphorus coagulant was not injected. The average influent and effluent total phosphorus concentrations at mode II were 0.5 ~ 1.0 mg/L and 0.27 mg/L, respectively. As for COD and BOD effluent concentrations, COD was 3.0 mg/L and BOD was 1.0 mg/L. Additionally, nitrogen removal rates were high at low influent DO concentration. In conclusion, a new process, biofilter packed with granular sulfur is expected to treat high-rate nitrogen wastewater and expected to be utilized as an alternative of technological innovation for the nitrogen treatment.

A Study on the Importance Priority of Expected Effect Factors in the Introduction of Cloud Computing Service (클라우드 컴퓨팅 서비스 도입 시 기대효과 요인의 중요도 우선순위 도출에 관한 연구)

  • Kang, Da-Yeon;Kim, Sang-Hyun
    • The Journal of the Korea Contents Association
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    • v.20 no.4
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    • pp.564-570
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    • 2020
  • The development of cloud computing service technologies plays a particularly important role in the enterprise. The introduction of cloud computing services by companies is also contributing to the improvement of market value and changes in corporate earnings. In this study, we demonstrated the importance of priorities by selecting sub-items that can be evaluated by separating the expected characteristics of efficiency, economics, and dependencies when introducing cloud computing services. The main priority items were selected based on prior research and the survey was conducted by IT system experts. Using AHP analysis method, the results of performing a double contrast bridge resulted in the final priority. The findings will later be used as important data to determine an enterprise's decision to accept cloud computing services.

Maintenance Limit Renewal Policy for Inferiority System based on Opportunity Cost (기회비용을 고려한 열화시스템의 보전한계갱신정책)

  • 박상민;김연수
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.17 no.32
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    • pp.233-242
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    • 1994
  • This study deals with the derivative adverse minimum for inferiority system depends on continuose operating under infinite planning horizon. This planning will be accomplished by maintenance limit renewal policy in consideration of opportunity cost which affects system by failure during operation periods and expected cost under nomal operation states. By the results, we will be expected incresing total efficiency for the system by optimal renewal policy.

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A Study on Thermodynamic Efficiency for HTSE Hydrogen and Synthesis Gas Production System using Nuclear Plant (원자력 이용 고체산화물 고온전기분해 수소 및 합성가스 생산시스템의 열역학적 효율 분석 연구)

  • Yoon, Duk-Joo;Koh, Jae-Hwa
    • Transactions of the Korean hydrogen and new energy society
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    • v.20 no.5
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    • pp.416-423
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    • 2009
  • High-temperature steam electrolysis (HTSE) using solid oxide cell is a challenging method for highly efficient large-scale hydrogen production as a reversible process of solid oxide fuel cell (SOFC). The overall efficiency of the HTSE hydrogen and synthesis gas production system was analyzed thermo-electrochemically. A thermo-electrochemical model for the hydrogen and synthesis gas production system with solid oxide electrolysis cell (SOEC) and very high temperature gas-cooled reactor (VHTR) was established. Sensitivity analyses with regard to the system were performed to investigate the quantitative effects of key parameters on the overall efficiency of the production system. The overall efficiency with SOEC and VHTR was expected to reach a maximum of 58% for the hydrogen production system and to 62% for synthesis gas production system by improving electrical efficiency, steam utilization rate, waste heat recovery rate, electrolysis efficiency, and thermal efficiency. Therefore, overall efficiency of the synthesis production system has higher efficiency than that of the hydrogen production system.

Structure and Characteristics of Tandem Solar Cell Composed of Dye-sensitized Solar Cell and Thermoelectric Generator (염료감응형 태양전지와 열전발전소자를 결합한 복합 태양전지의 구조 및 특성)

  • Lee, Dong-Yoon;Song, Jae-Sung;Lee, Won-Jae;Kim, In-Sung;Jeong, Soon-Jong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.4
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    • pp.357-362
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    • 2005
  • The tandem solar cell composed of a dye-sensitized solar cell (DSC) and a thermoelectric generator (TEG) was designed. In such new cell, the characteristics of DSC and TEG were investigated. DSC uses the wavelength range of 380∼750 nm and has the maximum efficiency of below 10 %. If the solar light transmitted through DSC can be converted to heat energy, TEG can generate electric energy using this heat energy. By this means, it is possible to utilize most of solar energy in the wavelength range of 350∼3000 nm for electric generation and it can be expected to obtain higher solar energy conversion efficiency exceeding the known limit of maximum efficiency. For this purpose we suggest the tandem solar cell constructed with DSC and TEG. In this structure, DSC has a carbon nanotube film as a counter electrode of DSC in order to collect the solar light and convert it to heat energy. We measured the I-V characteristics of DSC and TEG, assembled to the tandem cell. As a result, it was shown that DSC with carbon nanotube and TEG had the efficiency of 9.1 % and 6.2 %, respectively. From this results, it is expected that the tandem solar cell of the new design has the possibility of enhanced conversion efficiency to exceed above 15 %.

Analysis of the Efficiency According to Resonant Repeater Application in Magnetic Resonant Wireless Power Transfer System (자기공진방식의 무선전력전송 시스템에서 공진 중계기 적용 여부에 따른 전력전송 효율 분석)

  • Baek, Seung-Myung;Kim, Dong-Eun;Shon, Jin-Geun
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.67 no.4
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    • pp.221-226
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    • 2018
  • In this paper, the power transfer efficiency analysis based on the resonant repeater in a magnetic resonance wireless power transfer system is proposed. The efficiency of the magnetic resonance method was verified by comparing the general frequency with the resonance frequency. The resonance repeater was arranged to increase the efficiency and increase the transfer distance. When using resonant repeaters, the maximum efficiency increase is about 36.23[%] and the transfer distance was extended to more than 20[cm]. Through this study, confirmed the effect of using resonance repeaters in wireless power transfer system. As a result, it can be expected that the overall technology related to wireless power transfer system will be more valuable for energy-IT technology.