• Title/Summary/Keyword: Energy storage

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Recent Progress in Layer-by-layer Assembly of Nanomaterials for Electrochemical Energy Storage Applications

  • Kim, Sung Yeol
    • Journal of the Korean Electrochemical Society
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    • v.17 no.3
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    • pp.139-148
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    • 2014
  • Electrochemical energy-storage devices such as batteries and supercapacitors are important components in emerging portable electronic device, electric vehicle, and clean energy storage and supply technologies. This review describes recent progress in the development of nanostructured electrodes, the main component of the electrochemical energy-storage device, prepared by layer-by-layer (LbL) electrostatic assembly. Major advantages associated with, and challenges to, the fabrication of LbL electrodes, as well as the future outlook for expanding the application of LbL techniques, are discussed.

A Study on Capacity Design of Energy Storage System for Urban Transit System (도시철도시스템용 에너지저장시스템 용량설계에 관한 연구)

  • Lee, Han-Min;Kim, Gil-Dong;Lee, Chang-Mu
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.697-700
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    • 2007
  • Six thousands of vehicles are operated on Korean urban transit system. 95% of them have regeneration system. Especially, the VVVF-Inverter vehicle has a merit of the highest regeneration rate. Therefore, the energy storage system is needed to be developed to use regeneration energy when the vehicle is braking. Therefore, Measuring regeneration energy in the substation need to know how much regeneration energy occurs, how much capacity of energy storage system is needed. After measuring regeneration energy, we design the capacity of energy storage system.

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The Study of Economical Efficiency for the Ice Storage System of more Energy Consumption Building (에너지 다소비형 건물 축냉 시스템의 경제성에 관한 연구)

  • Lee, Je-Myo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.10
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    • pp.733-738
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    • 2012
  • It is important issue to reduce the electric energy to save the operating cost of HVAC system. Even if electrical energy is the clean energy, it is difficult and takes high cost for storage of electricity. These cause the high peak load of electric energy for HVAC in summer season. In korea, government impose the electric charge with several grade for the purpose of cut-off the peak load of electricity. Government has a policy to support to design and install the heat/ice storage system using midnight electricity. In this study, analysis of cooling load and operating characteristics for ice storage system are performed. And, also economical efficiency is compared between ordinary charge system of electricity and midnight rate charge of electricity. The systematic and economical supports are needed for expansion of usage of energy saving equipments.

Synthesis and Properties of Ionic Liquids:Imidazolium Tetrafluoroborates with Unsaturated Side Chains

  • Min, Gwan-Hong;Yim, Tae-eun;Lee, Hyun-Yeong;Huh, Dal-Ho;Lee, Eun-joo;Mun, Jun-young;Oh, Seung M.;Kim, Young-Gyu
    • Bulletin of the Korean Chemical Society
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    • v.27 no.6
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    • pp.847-852
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    • 2006
  • Imidazolium tetrafluoroborate ionic liquids having unsaturated aliphatic side chains were synthesized and characterized. Most of them are liquid at room temperature and all of them are stable up to $300{^{\circ}C}$. Some imidazolium tetrafluoroborates with an allylic side chain showed much wider voltage windows on the platinum electrode, better conductivities, and lower viscosities compared with the corresponding ionic liquids containing the saturated side chains.

Design method of heat storage type ground source heat pump system considering energy load pattern of greenhouse (원예시설의 에너지 부하패턴을 고려한 축열식 지열시스템 설계법에 관한 연구)

  • Yu, Min-Gyung;Nam, Yujin;Lee, Kwang Ho
    • KIEAE Journal
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    • v.15 no.3
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    • pp.57-63
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    • 2015
  • Purpose: Ground source heat pump system has been attracted in the horticulture industry for the reduction of energy costs and the increasing of farm income. Even though it has higher initial costs, if it uses in combination with heat storage, it is able to reduce the initial costs and operate efficiently. In order to have significant effect of heat storage type ground source heat pump system, it is required to design the capacity considering various conditions such as energy load pattern and operating schedule. Method: In this study, we have designed heat storage type ground source heat pump system in 5 cases by the operating schedule, and examined the system to find the most economic and having superb performance regarding the system COP(Coefficient of Performance) and energy consumption, using dynamic energy simulation, TRNSYS 17. Result: Conventional ground source heat pump system has lower energy consumption than heat storage type, but following the result of LCC(Life Cycle Cost) analysis, the heat storage type was more economic due to the initial costs. In addition, it has the most efficient performance and energy costs in the case of the smallest heat storage time.

Synthesis and Physicochemical Properties of Ionic Liquids: 1-Alkenyl-2,3-dimethylimidazolium Tetrafluoroborates

  • Min, Gwan-Hong;Yim, Tae-Eun;Lee, Hyun-Yeong;Kim, Hyo-Jin;Mun, Jun-Young;Kim, Sang-Mi;Oh, Seung-M.;Kim, Young-Gyu
    • Bulletin of the Korean Chemical Society
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    • v.28 no.9
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    • pp.1562-1566
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    • 2007
  • 1-Alkenyl-2,3-dimethylimidazolium tetrafluoroborate ionic liquids having an olefinic substituent were synthesized and characterized. Among them, [AMMIm]BF4 with an allyl group showed lower viscosity, higher ionic conductivity, and a wider electrochemical window compared with its analogue having a saturated alkyl substituent. An EDLC with [AMMIm]BF4 showed better performance than that with [PMMIm]BF4, too.

A Study on the Annual Storage Efficiency of Concentric Evacuated Tube Solar Energy Collector System (이중진공관형 태양열 집열기의 연간 집열효율에 관한 연구)

  • Kim, Ki-Chul;Paeng, Jin-Gi;Yoon, Young-Hwan
    • Journal of the Korean Solar Energy Society
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    • v.28 no.4
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    • pp.50-55
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    • 2008
  • The Storage efficiency of concentric evacuated tube solar collector is tested for one year from January 1st to December 31st under the real sun condition. The testing equipment is operated continuously for three days without cooling the storage tank. Daily storage efficiency is obtained from dividing stored energy in the storage tank by solar insolation on the solar collector for each day. Daily averaged temperature of the storage tank is lowest in January and highest in August. Monthly averaged storage efficiency is also lowest in November and highest in June. Therefore, it can be said that the storage temperature and the storage efficiency are roughly proportional to outdoor temperature. Furthermore, the daily storage efficiency is reversely proportional to $(T_s-T_a)/I_c$ where $T_s$ and $T_a$ are daily averaged storage temperature and outdoor temperature from sunrise to sunset, and $I_c$ is total insolation on the solar collector for a day.