• Title, Summary, Keyword: Storage System

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A New Approach to Servo System Design in Hard Disk Drive Systems

  • Kim, Nam-Guk;Choi, Soo-Young;Chu, Sang-Hoon;Lee, Kang-Seok;Lee, Ho-Seong
    • Transactions of the Society of Information Storage Systems
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    • v.1 no.2
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    • pp.137-142
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    • 2005
  • In this paper, we propose a new servo system design strategy to reduce the position error signal(PES) and track mis-registration(TMR) in magnetic disk drive systems. The proposed method provides a systematic design procedure based on the plant model and an optimal solution via an optimization with a 'Robust Random Neighborhood Search(RRNS)' algorithm. In addition, it guarantees the minimum PES level as well as stability to parametric uncertainties. Furthermore, the proposed method can be used to estimate the performance at the design stage and thus can reduce the cost and time for the design of the next generation product. The reduction of PES as well as robust stability is demonstrated by simulation and experiments.

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Development of Flywheel Energy Storage System (플라이휠에 의한 에너지 저장 장치 개발)

  • Kim, W.H.;Kim, J.S.;Rim, G.H.
    • Proceedings of the KIEE Conference
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    • pp.1924-1926
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    • 1997
  • With the development of power electronics, many new energy storage systems such as the superconducting magnetic energy storage, the flywheel energy storage, and the capacitive energy storage, etc. are being intensively studied recently in order to replace battery in some special applications, Among these innovative energy storage systems, the flywheel system exhibits some unique features such as high power density, easy maintenance and longer lifetime. This paper introduces the novel flywheel energy storage system. Operation and features of the system are illustrated and verified on a 6kVA, 20kHz IPM based experimental circuit for O/A application. The Halbach Array Motor is selected of the design of the three phase motor/generator for the flywheel energy storage system.

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Demonstration to Operate and Control Frequency Regulation of Power System by 4MW Energy Storage System (4MW 에너지저장장치의 전력계통 주파수 조정 운전제어를 위한 실증)

  • Lim, Geon-Pyo;Han, Hyun-Gyu;Chang, Byung-Hoon;Yang, Seung-Kwon;Yoon, Yong-Beum
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.3
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    • pp.169-177
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    • 2014
  • Operation and control system has been installed and tested to use energy storage system(ESS) for frequency regulation at 4MW class of ESS demonstration facility installed at Jeju island, Korea in 2013. Simulation tests were performed by programing language C# for power system of Jeju island to develop control algorithm. Site simulation tests were performed in control system itself without connecting power system and energy storage system. Control algorithm was coded, modified and tested to load to controller and communication system and human-machine interface were developed and tested in the process of simulation tests. After similar results to that of simulation tests by programing language were obtained, power system and energy storage system demonstration facility were connected to control system by communication system. Energy storage system for frequency regulation was tested for actual frequency and simulation frequency. The site tests showed the similar results to that of simulation tests and the control systems is possible to be operated for frequency regulation. Faster response of energy storage system for frequency regulation, less costs and less capacity of energy storage systems which cover for frequency regulation of power plants. It is expected that more studies for time-reduction and time-delay elements can make less capacity of energy storage system cover more role of frequency regulation of power plants.

Development of Thermal Storage System in Plastic Greenhouse(II) -Thermal performance of solar greenhouse system for hydroponic culture- (플라스틱 온실(溫室)의 열저장(熱貯藏) 시스템의 개발(開發)에 관(關)한 연구(硏究)(II) -수경재배용(水耕栽培用) 태양열(太陽熱) 온실(溫室) 시스템의 열적(熱的) 성능(性能)-)

  • Kim, Y.H.;Koh, H.K.;Kim, M.K.
    • Journal of Biosystems Engineering
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    • v.15 no.2
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    • pp.123-133
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    • 1990
  • Thermal performance of a solar heating plastic greenhouse designed for a hydroponic system was studied. The system was constructed with the air-water heat exchanger and thermal storage tank that were combined with hydroponic water beds. Experiments were carried out to investigate the daily average heat stored and released in thermal storage tank, average solar energy collection efficiency, average coefficient of performance, average oil reduction factor of thermal storage system, and the heat transfer coefficient during the nighttime in plastic greenhouse. The results obtained in the present study are summarized as follows. 1. Daily average heat stored in thermal storage tank and released from the thermal storage tank was 1,259 and $797KJ/m^2$ day, respectively. 2. The average solar energy collection efficiency of thermal storage tank was 0.125 during the experiment period. And the average coefficient of performance of thermal storage system in plastic greenhouse was 3.6. 3. The average oil reduction factor of thermal storage system and the heat transfer coefficient during the nighttime in plastic greenhouse were found to be 0.52 and $4.3W/m^2\;hr\;^{\circ}C$, respectively.

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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.

Experimental Study on Calcium Chloride Impregnated Perlite for Thermochemical Heat Storage (염화칼슘이 함침된 펄라이트를 이용한 화학축열에 대한 실험적 연구)

  • Jung, Han Sol;Kim, Hak Seong;Hwang, Kyung Yub;Kim, Kwang Ho
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.3
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    • pp.123-127
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    • 2015
  • Thermochemical heat storage is a cutting-edge technology which can balance the energy usage between supplies and demands. Recent studies have suggested that thermochemical heat storage has significant advantages, compared to other storage methods such as latent heat storage or sensible heat storage. Nevertheless, ongoing research and development studies showed that the thermochemical heat storage has some serious problems. To bring the thermochemical heat storage method into market, we introduce experimental setup with composite material using perlite that supports calcium chloride sorbent. Also, to compare thermal properties with composite material, we used pure thermochemical material. Then, we found that the composite material has higher heat storage density by mass than pure calcium chloride. Moreover, it can be easily regenerated, which was impossible in the pure thermochemical materials.

An Effect of Insulated Raft on Longterm Hot Water Storage (Insulated Raft가 장기온수저장에 미치는 영향)

  • Pak, Ee-Tong;Cho, Woon
    • Solar Energy
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    • v.17 no.1
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    • pp.79-91
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    • 1997
  • Thermal energy storage system used a storage tank is a reasonable method to solve energy problem. In thermal energy storage system, energy collected from many types of heat source is stored in a storage tank and then supply to load at the time is in demand. In this study, flow characteristics and storage efficiency were analysed by using a insulated raft in longterm hot water storage system. From the experiment it is found that insulated raft has a important role in longterm hot water storage system and storage efficiency can be obtained to 96% using inletport type and insulated raft together.

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Dynamic simulation of the ice storage cooling system (빙축열 냉방 시스템의 동적 시뮬레이션)

  • 한도영;이준호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.6
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    • pp.815-823
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    • 1999
  • A dynamic simulation program may be used for the development of effective control algorithms for the ice storage cooling system. Simplified effective dynamic models for an ice-on-coil type storage tank, a screw chiller, a water-to-air heat exchanger, three way valves, pipes, pumps, temperature sensors, and controllers were developed. And a dynamic simulation program for the ice storage cooling system was developed by using these dynamic models. Control algorithms for the full storage system were also selected and analyzed in order to show the effectiveness of these models. From the simulation results, it may be concluded that the simulation program developed in this study can be effectively used for the development of improved control algorithms for the ice storage cooling system.

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Dynamic Analysis of Cool Thermal Storage Air Conditioning System (빙축열 에어컨의 동적 사이클 해석)

  • Koh, Jae-Yoon;Seo, Tae-Beom
    • Journal of the Korean Solar Energy Society
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    • v.28 no.1
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    • pp.65-74
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    • 2008
  • In this study, dynamic characteristics analysis of AC system is investigated using a cool thermal storage system. A analysing program for cool thermal storage AC system is developed. The performances are studied by several variables and dynamic characteristics. Comparing the result at conventional operation condition with that at the condition using ice storage system, this study showed the effects of the sub cooled degree, superheated degree, efficiency of compressor and evaporating temperature. At the condition using thermal storage system, the thermal storage process was operated during midnight being not needed the cooling of the AC unit through the continuous running of the condenser. The refrigerant was sub-cooled using stored energy after being discharged from the air source condenser during the daytime. The COP was increased owing to the sub-cooling of refrigerant during daytime, thus the power consumption was effectively decreased.

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.