• Title/Summary/Keyword: energy storage

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Heat Transfer Characteristics and Hydrogen Storage Kinetics of Metal Hydride-Expended Graphite Composite (금속수소화물-팽창흑연 복합체의 열전달 특성 및 수소 저장 특성)

  • LEE, PYOUNGJONG;KIM, JONGWON;BAE, KIKWANG;JEONG, SEONGUK;KANG, KYOUNGSOO;JUNG, KWANGJIN;PARK, CHUSIK;KIM, YOUNGHO
    • Journal of Hydrogen and New Energy
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    • v.31 no.6
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    • pp.564-570
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    • 2020
  • Metal hydride is suitable for safe storage of hydrogen. The hydrogen storage kinetics of the metal hydride are highly dependent on its heat transfer characteristics. This study presents a metal hydride-expended graphite composite with improved thermal conductivity and its hydrogen storage kinetics. To improve the heat transfer characteristics, a metal hydride was mixed and compacted with a high thermal conductivity additive. As the hydrogen storage material, AB5 type metal hydride La0.9Ce0.1Ni5 was used. As an additive, flakes-type expended graphite was used. With improved heat transfer characteristics, the metal hydride-expended graphite composite stores hydrogen four times faster than metal hydride powder.

Management of the Energy Storage System for a microgrid (마이크로그리드에의 적용을 위한 에너지 저장장치의 관리)

  • Kim, Sung-Hyun;Lee, Kye-Byung;Son, Kwang-M.
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.505_506
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    • 2009
  • This paper presents effective operation methods for the battery energy storage applied to a microgrid. In an islanded microgrid, energy storage is needed to satisfy an energy balance between generation and consumption. The microgrid can be classified according to the ratio of the sensitive load and renewable energy source in the microgrid. For effective management of the battery energy storage, based on the classified microgrid, suitable operation methods for the battery energy storage system are provided from well-known battery applications.

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Efficiency Improvement Effect Analysis for Marginal Storage Capacity in DC Electric Railway Systems (직류도시철도 시스템에서 저장장치 단위 용량 당 에너지 절감 효과 분석 연구)

  • Lee, Hansang;Yoon, Donghee;Kim, Hyungchul;Joo, Sung-Kwan;Jung, Hosung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.8
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    • pp.1159-1163
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    • 2014
  • This paper have been dealt with the analysis for energy efficiency improvement effect of unity storage capacity as a part of the energy storage application study to improve energy efficiency in the electric railway systems. Especially, in order to estimate the amount of energy saving according to the variation of power capacity of each storage, the current limit module was mounted on an existing DC electric railway loadflow program which is based on the analysis model for railway system and storages, and combined optimization algorithm to determine optimal voltage boundary.

Design of Controllers for Battery Energy Storage System (2차전지 전력저장시스템의 제어기 설계)

  • 한석우;전윤석;최규하;목형수
    • Proceedings of the KIPE Conference
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    • 1999.07a
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    • pp.431-434
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    • 1999
  • This paper presents design of controllers for battery energy storage system. The proposed battery energy storage system can be controlled to operate in the power conditioning mode or the inverter mode. The operation of this mode further divided into three cases: (a) in the peak load period, the load power supplied from the utility is minimized as far as possible; (b) in the off-peak load period, the utility supplies power to the load and charges the battery bank with automatic charging control; (c) in the medium load period, to save battery energy the real power flow out of the battery energy storage system is minimized. Besides, in all cases, the proposed battery energy storage system also automatically compensates the harmonics, subharmonics and reactive power factor in the utility side are much improved. Simulation results are presented by the effectiveness of the proposed controllers for battery energy storge system.

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A Study on the Development of Battery Energy Storage System (전지이용 전력저장장치 기술개발)

  • Hwang, Yong-Ha;Lee, Keun-Seob
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.905-907
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    • 1993
  • Demand for electricity is increasing annually. Especially, the daytime demand grawth shows higher than any other time period. So the big difference between maximum and minimum electrical demand becomes another important problem to be solved. The Battery Energy Storage System is chosen as one of the solutions among the sevral methods. The purpose of utilization of Battery Energy Storage System is to improve the daily load factor. Also, Battery Energy Storage System may be used for the load levelling or the load shifting as well as the spinning reserve. Up to now, only the pumped hydro power plant system has been operated on the commercial basis, but this system has so many constraints such as site, environmental effects, construction period, ect. Being considered current electrical power situation the development of electric storage system is in need latly. Among the various electric storage systems, Battery Energy System is chosen with the top priority because it has sevral merits to cover such as the short construction period, the demand site installation, and the food environmental characteristics.

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Cooling and Heating Energy Performance and Cost Analysis of Vertical Closed-loop Geothermal Heat Pump Coupled with Heat Storage Tank Compared to Conventional HVAC System (일반공조 시스템 대비 축열조와 연동된 수직밀폐형 지열히트펌프의 냉난방 에너지 성능 및 경제성 분석)

  • Kim, Min-Ji;Do, Sung-Lok;Choi, Jong-Min;Lee, Kwang Ho
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.11
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    • pp.81-87
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    • 2018
  • Among various types of geothermal heat pump systems, Vertical Closed-Loop Geothermal Heat Pump (VGSHP) has received increasing attention due to a variety of advantages such as the potential to be installed in a relatively small space and improved energy efficiency. In this research, the performance of VGSHP system coupled with heat storage tank was evaluated, by analyzing operational behavior of heat storage tank, the variations of heat pump energy performance due to the connection with heat storage tank, part load ratios characteristics of heat pump and the corresponding energy cost, compared to chiller and boiler based conventional system. The results of this study showed that the VGSHP system coupled with heat storage tank showed an energy saving effect of about 18% for cooling and about 73% for heating, and annual heating/cooling energy cost reduction of 43,000,000 KRW ($ 39,000), compared to the conventional air conditioning system. In addition, after considering both energy cost and initial investment cost including equipment, installation and auxiliary device expenses, payback period of approximately 11.8 years was required.

Energy Storage Application Strategy on DC Electric Railroad System using a Novel Railroad Analysis Algorithm

  • Lee, Han-Sang;Lee, Han-Min;Lee, Chang-Mu;Jang, Gil-Soo;Kim, Gil-Dong
    • Journal of Electrical Engineering and Technology
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    • v.5 no.2
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    • pp.228-238
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    • 2010
  • There is an increasing interest in research to help overcome the energy crisis that has been focused on energy storage applications in various parts of power systems. Energy storage systems are good at enhancing the reliability or improving the efficiency of a power system by creating a time gap between the generation and the consumption of power. As a contribution to the various applications of storage devices, this paper describes a novel algorithm that determines the power and storage capacity of selected energy storage devices in order to improve upon railroad system efficiency. The algorithm is also demonstrated by means of simulation studies for the Korean railroad lines now in service. A part of this novel algorithm includes the DC railroad powerflow algorithm that considers the mobility of railroad vehicles, which is necessary because the electric railroad system has a distinct distribution system where the location and power of vehicles are not fixed values. In order to derive a more accurate powerflow result, this algorithm has been designed to consider the rail voltage as well as the feeder voltage for calculating the vehicle voltage. By applying the resultant control scheme, the charging or discharging within a specific voltage boundary, energy savings and a substation voltage stabilization using storage devices are achieved at the same time.

Technology Characteristics of Hydrogen Storage and Its Technology Trend by the Patent Analysis (수소저장 기술특성 및 특허분석에 의한 기술동향)

  • Noh, Soon-Young;Rhee, Young-Woo;Kang, Kyung-Seok;Choi, Sang-Jin;Kim, Jong-Wook
    • Journal of Hydrogen and New Energy
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    • v.19 no.1
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    • pp.90-102
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    • 2008
  • Hydrogen storage is widely recognized as a critical enabling technology for the successful commercialization. There are a few different approaches for hydrogen storage technology. In this paper, characteristics of hydrogen storage technologies were analyzed from the literature survey. Also, The technology trend of hydrogen production was scrutinized based on patent analysis. In patent analysis the search range was limited to the open patents issued from 1996 to 2006. The technology trend of hydrogen storage was assessed by classifying each patent based on the publishing year, country, and the type of storage technology.

Designing for the Off-line UPS using SMB Flywheel Energy Storage System (초고속 플라이휠 에너지 저장시스템을 이용한 Off-line UPS 제작)

  • 최재호
    • Proceedings of the KIPE Conference
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    • 2000.07a
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    • pp.689-692
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    • 2000
  • This paper presents a designing for the Off-line UPS usig SMB Flywheel Energy Storage System. This described flywheel energy storage system is designed to replace of the conventional EMB(Electro Mechanical Battery) system. To realize the high efficiency and to minimize the torque ripple the waveform of the inverter output current is controlled to be sinusoidal. The actual performance of the Off-line UPS using flywheel energy storage system is described. The prototype device was manufactured, The experimental result has good characteristics at a time of power transition region and regeneration modes,

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