• Title/Summary/Keyword: Optimal charge and discharge

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Optimal Scheduling of Ice Storage System with Prediction of Cooling Loads (예측 냉방부하를 이용한 빙축열시스템의 최적 운전계획)

  • 이경호;최병윤;주용진;이상렬;한승호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.11
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    • pp.982-993
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    • 2000
  • This paper describes an optimal control scheduling of an encapsulated ice storage system with a chiller of nominal chiller 34RT(103,200kcal/hr) and an ice storage tank of 170RT-hrs(514,080 kcal). The optimization technique used in the study is dynamic programing. The objective function is summed cost during a day including charge and discharge periods. Control strategies being used commercially are chiller priority and storage priority control. In chiller priority control, the chiller is allowed to run at full capacity during the day, subject to limitations of the building load, and the ice is only melted when and if the load exceeds the chillers full capacity. In contrast to chiller priority control, the aim in storage priority control is to melt as much as ice as possible during the day time period. The system simulation calculates the operation costs for the three control strategies in the condition of the same cooling load and the same ice storage system. The simulation period is a day, assuming that initially the tank is stored fully and the cooling load is perfectly predicted for the scheduling. Also Final state of the tank is to be charged fully.

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A Study on Establishing Operation Mathematical Model for Optimum Capacity Estimation of the ESS Applications for each in the Nationwide Perspective (국가적 관점에서 용도별 ESS 적정용량 산정을 위한 운전수리모델 수립에 대한 연구)

  • Kim, Jung-Hoon;Youn, Seok-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.6
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    • pp.969-978
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    • 2016
  • Around the world are increasing the demand for ESS. Currently, the domestic is expected to benefit by operating ESS. In the domestic, it is expected to benefit from operations of the installed ESS because of the introduction of ESS less capacity. However ESS capacity to the maximum profit occurs is unknown. ESS is different from the charge-discharge characteristics and the reserve to replace, depending on the application. Therefore, it should be established in accordance with the ESS optimal capacity according to the purpose used because it can maximize the quality and efficiency of the electric energy. To the ESS optimal capacity estimation by the purpose used, It should compare the investment cost caused by ESS facility installation and operation cost caused by operating ESS. In this paper, the operation mathematical model for estimating marginal operation costs established. In operation mathematical model, operating cost is considered fuel cost and no-load cost start-up cost. Because no-load cost and start-up cost are not related to cost and power plant output, there are expressed an integer variable costs as a step function.

A Study on Methodology of Optimal Operation of BESS and Diesel Generators in a Microgrid Considering Efficiency Characteristics According to the Power Ratios of Diesel Generators (디젤발전기의 출력비에 따른 효율을 고려한 마이크로그리드에서의 BESS와 디젤발전기의 최적 운영 기법에 관한 연구)

  • Lee, Byung Ha
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.4
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    • pp.539-546
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    • 2016
  • With the growing interest of microgrid systems all over the world, many studies on microgrid operation are being carried out. The battery energy storage system(BESS) and the diesel generator are key equipments in the microgrid. In this paper, we analyze the characteristics of fuel consumption according to the power ratio of the diesel generator. Then, the formula to represent the unit cost of generation according to the power ratio of the diesel generator is derived. A new modeling of battery operation is presented considering the lifetime reduction according to increasing the cycles of charge/discharge operation of the battery. The methodology of determining the optimal operation of the battery and the diesel generator is presented by the use of the formula of fuel consumption of the diesel generator and the new modeling of battery operation. It is shown that this optimization methodology can be applied effectively for economical operation of the BESS and the diesel generator of a microgrid by case studies.

Synthesis and Properties of Nonfluoro Aminated Poly(vinylbenzyl chloride-co-ethyl methacrylate-co-styrene) Anion Exchange Membranes for MCDI Process (막 축전식 탈염용 비불소계 아민화 Poly(vinylbenzyl chloride-co-ethyl methacrylate-co-styrene) 음이온교환막의 합성 및 특성)

  • Koo, Jin-Sun;Kwak, Noh-Seok;Hwang, Taek-Sung
    • Polymer(Korea)
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    • v.36 no.5
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    • pp.564-572
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    • 2012
  • A terpolymer of vinylbenzyl chloride-co-ethyl methacrylate-co-styrene (VBC-EMA-St) was prepared for membrane capacitive deionization (MCDI) by radical polymerization and amination reaction of various amination times. Nonfluoro aminated VBC-EMA-St anion-exchange membranes were characterized by Fourier transform infrared (FTIR) spectrometry. Molecular weight, polydispersity and thermal stability were obtained by gel permeation chromatography (GPC) and thermogravimetric analysis (TGA). The basic properties such as water uptake, ion exchange capacity, electrical resistance and CDI charge-discharge current were measured. The optimal values of ion exchange capacity, water uptake, electrical resistance and molecular weight of synthesized anion-exchange membrane were 1.69 meq/g, 23.7%, 1.61 ${\Omega}{\cdot}cm$ and $3.4{\times}10^4$ g/mol, respectively. As compared with conventional membrane, the pattern of cyclic charge-discharge current of synthesized anion-exchange membrane indicated efficient electrosorption and desorption.

Comparative analysis of the minimum capacity of an ice-on-coil thermal storage system for various operation strategies (관외 빙착형 빙축열시스템의 운전방식에 따른 최소용량 비교)

  • 이대영;정성훈;강병하
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.3
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    • pp.401-413
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    • 1999
  • An ice storage cooling facility with cooling capacity of 150㎾ has been constructed for the purpose of developing optimal design and control strategy for an ice storage system. As the first step to this purpose, a computer program has been developed to simulate the operation of the ice storage system and examined precisely by comparing the results with those measured from the test facility. With the simulation program verified from the comparison, a design procedure has been developed to determine the minimum capacity required for each operation strategy available commercially. It is shown that the minimum sizes of the chiller and the storage tank are strongly dependent on the control strategy, i.e., chiller priority or storage priority, but less affected by the arrangement method, i.e., chiller upstream or chiller downstream.

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Study on Power Control and Optimal Management for Dog-Horse Robot (견마로봇의 전력제어 및 최적 운용에 대한 연구)

  • Kang, Tae-Ha;Huh, Jin-Wook;Kim, Jun;Kang, Sin-Cheon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.3
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    • pp.343-348
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    • 2010
  • Recently, unmanned electric vehicles are increasingly interested among all of the world since they can provide low exhaust gas, high efficiency and high mobility. To exploit their silent maneuver and high mobility, unmanned electric vehicles have been developed since early 1980's for military. However, it is not easy to design and control a power system satisfying operating duration and mobility performance requirements based on various mission profiles for military use under the conditions of limited space and weight. Moreover it is also necessary to prevent over-charge, over-discharge and voltage unbalance between cells of battery to secure high voltage battery which is serially connected with muti-cells. In this paper, we presents power control and optimal management method for the dog-horse robot which adopts a electric power system and suggests a guide-line to manage and control to secure high voltage battery.

Design of a 49kW high efficiency bidirectional DC-DC converter for charge and discharge of high voltage battery in HEV (하이브리드 자동차 고전압 배터리 충, 방전을 위한 49kW급 고효율 양방향 DC/DC 컨버터 설계)

  • Yang, Jin-Young;Yoon, Chang-Woo;Park, Sung-Sik;Choi, Se-Wan;Park, Rae-Kwan;Chang, Seo-Geon
    • Proceedings of the KIPE Conference
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    • 2007.11a
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    • pp.21-23
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    • 2007
  • In this paper a high efficiency bi-directional DC-DC converter for hybrid vehicles is proposed. The proposed converter a three-phase half-bridge interleaved ZVS converter, is designed to have high efficiency in the main operation range. The component ratings are calculated, the actual devices are selected, and the efficiency analysis has been performed to determine optimal ZVS range. The input and output current ripples are significantly reduced due to the interleaved operation. The dual loop control for the interleaved three-phase converter is also presented. To confirm the proposed convert ter, The simulation and experimental results are presented.

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Modeling of the dynamic behavior of a 12-V automotive lead-acid battery (12V 차량용 납축전지의 동적 거동 모델링)

  • Kim, Sung Tae;Lee, Jeong Bin;Kim, Ui Seong;Shin, Chee Burm
    • Journal of Energy Engineering
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    • v.22 no.2
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    • pp.175-183
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    • 2013
  • For the optimal design of the vehicle electric system, it is important to have a reliable modeling tool to predict the dynamic behavior of the automotive battery. In this work, a one-dimensional modeling was carried-out to predict the dynamic behaviors of a 12-V automotive lead-acid battery. The model accounted for electrochemical kinetics and ionic mass transfer in a battery cell. In order to validate the modeling, modeling results were compared with the experiment data of the dynamic behaviors of the lead-acid batteries of two different capacities that were mounted on the automobiles manufactured by Hyundai Motor Company. The discharge behaviors were measured with various discharge rates of C/3, C/5, C/10, C/20 and combination. And dynamic behaviors of charge and discharge were measured. The voltage curves from the experiment and simulation were in good agreement. Based on the modeling, the distributions of the electrical potentials of the solid and solution phases, and the current density within the electrodes could be predicted as a function of charge and discharge time.

Comparison of Learning Techniques of LSTM Network for State of Charge Estimation in Lithium-Ion Batteries (리튬 이온 배터리의 충전 상태 추정을 위한 LSTM 네트워크 학습 방법 비교)

  • Hong, Seon-Ri;Kang, Moses;Kim, Gun-Woo;Jeong, Hak-Geun;Beak, Jong-Bok;Kim, Jong-Hoon
    • Journal of IKEEE
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    • v.23 no.4
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    • pp.1328-1336
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    • 2019
  • To maintain the safe and optimal performance of batteries, accurate estimation of state of charge (SOC) is critical. In this paper, Long short-term memory network (LSTM) based on the artificial intelligence algorithm is applied to address the problem of the conventional coulomb-counting method. Different discharge cycles are concatenated to form the dataset for training and verification. In oder to improve the quality of input data for learning, preprocessing was performed. In addition, we compared learning ability and SOC estimation performance according to the structure of LSTM model and hyperparameter setup. The trained model was verified with a UDDS profile and achieved estimated accuracy of RMSE 0.82% and MAX 2.54%.

Effect of Cathode/anode Weight Ratio in $LiCoO_2/MPCF$ Cell ($LiCoO_2/MPCF$전지에서 정$\cdot$부극 중량비의 영향)

  • Kim Sang-Pil;Cho Jeong-Soo;Kim Hee-Je;Park Jeong-Hu;Yun Mun-Soo
    • Journal of the Korean Electrochemical Society
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    • v.2 no.2
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    • pp.75-80
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    • 1999
  • Li-ion cells employ lithium transtion metal oxide as the cathode material and carbon as anode material. To manufacture Li-ion cell with higher capacity and better cycle life, the utilization of electrode materials should be as high as possible without lithium deposition onto the carbon surface during charging. A careful design of cell balance between cathode and anode materials as well as a proper charge method is a key factor to design Li-ion cell with long cycle life. In this study, we investigated the effect of cathode/anode weight ratio on the performance of $LiCoO_2/MPCF$ cell. First we evaluated the charge-discharge behaviours of half-cells. And cylindrical Li-ion cells were fabricated using graphitized MPCF anode and $LiCoO_2$ cathode. The voltage profiles for each half-cell in $LiCoO_2/MPCF$ cell were measured by using lithium metal as a reference electrode. Also, we evaluated the cyclic performance of $LiCoO_2/MPCF$ cells according to weight ratio. From the result of experiment $LiCoO_2$ cathode utilization was independent of weight ratio, but MPCF anode utilization was dependant on weight ratio. Also, the optimal weight ratio of $LiCoO_2/MPCF$ cell was found to be $2.0\~2.2$.