• Title, Summary, Keyword: Optimal operation

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An Evaluation of Chiller Control Strategy in Ice Storage System for Cost-Saving Operation (운전비 절감을 위한 빙축열시스템 냉동기 운전기법 평가)

  • Lee, Kyoung-Ho;Choi, Byoung-Youn;Lee, Sang-Ryoul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.2
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    • pp.97-105
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    • 2008
  • This paper presents simulated and experimental test results of optimal control algorithm for an encapsulated ice thermal storage system with full capacity chiller operation. The algorithm finds an optimal combination of a chiller and/or a storage tank operation for the minimum total operation cost through a cycle of charging and discharging. Dynamic programming is used to find the optimal control schedule. The conventional control strategy of chiller-priority is the baseline case for comparing with the optimal control strategy through simulation and experimental test. Simulation shows that operating cost for the optimal control with chiller on-off operation is not so different from that with chiller part load capacity control. As a result from the experimental test, the optimal control operation according to the simulated operation schedule showed about 14 % of cost saving compared with the chiller-priority control.

The Study of Optimal Operation Development of PV + ESS Active System for Zero Energy Building (제로에너지건물 구축을 위한 PV + ESS 액티브 시스템의 최적운영개발에 관한 연구)

  • Woo, Sung-Min;Moon, Jin-Chel;Ahn, Jong-Wook;Kim, Yong-Ha
    • Journal of the Korean Solar Energy Society
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    • v.39 no.5
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    • pp.53-63
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    • 2019
  • This paper in order to efficiently operate zero energy buildings developed a methodology for optimal operation of PV + ESS active systems. This program consists of three steps. First step is PV optimal operation and second step is PV + ESS optimal operation. Third step is the analysis of the results by PV + ESS optimal operation. The optimal operation of PV + ESS was calculated by using Dynamic Programming (DP). Therefore, the optimal capacity and operating plan of PV + ESS in this study are calculated for electric load at building. This paper conducted case study to verify the validity of the developed algorithm. Also, the sensitivity analysis analyzed the effect of each variable on the optimal operation.

Development of an operation and control software for electro-hydraulic (전자유압식 CVT의 운용 및 제어 소프트웨어 개발과 실시간 제어)

  • Kwan, H. B.;Kim, K. W.;Kim, H. S.;Eun, T.;Park, C. I
    • Journal of the korean Society of Automotive Engineers
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    • v.15 no.3
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    • pp.36-46
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    • 1993
  • In CVT vehicle, the engine speed is completely decoupled from the vehicle speed within the range from maximum transmission ratio to minimum transmission ratio. This allows the engine to operate in optimal state(e.g. best fuel economy or maximum power mode.) In this study, the CVT control algorithm for optimal operation of engine is suggested. In order to implement the real time digital control of electro-hydraulic CVT system, a software called CVTCON has been developed. CVTCON also includes the CVT operation module, (2) system test module, (3) system control module and (4) data management module. By using the CVTCON and the electro-hydraulic CVT system, two modes of experiments were carried out: constant throttle opening mode and acceleration mode. From the experimental result, it was found that the algorithm suggested in this study showed optimal operation of the CVT system.

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A Study on the Optimal Operation of the Private Cogeneration System (민생용 열병합발전시스템의 최적운전에 관한 연구)

  • Lyu, Seung-Heon;Lee, Jong-Bum;Kim, Chang-Soo
    • Proceedings of the KIEE Conference
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    • pp.896-898
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    • 1996
  • This paper presents the optimal operation scheduling of the private cogeneration system connected with auxiliary equipments. And the optimal size of auxiliary equipments is determined through evaluations of the minimum operation cost. The optimal operation scheduling is established by using the linear programming method. Simulation results show that the auxiliary boiler is operated as an economical facility but the thermal storage tank is used as a back up facility for emergency.

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Study on the Optimal Operation of ESS Considering Urban Railway Load Characteristic (도시철도 부하특성을 고려한 ESS의 최적 운영방안 연구)

  • Heo, Jae-Haeng;Shin, Seungkwon;Park, Jong-young;Kim, Hyeongig
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.10
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    • pp.1508-1516
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    • 2015
  • This paper proposes the optimal operation of ESS (Energy Storage System) in the substation of urban railway in an economical point of view. Since the load patterns of urban railway have different characteristics with the general power demand pattern, the characteristics motivate us to develop the optimal operation algorithm for ESS under Korean electricity billing system. We also introduce two different ESS operation strategies for peak load shaving and electricity consumption charge minimization respectively, and formulate each scheme. Historical data from Namgwangju substation are used for economical comparison of the strategies. The results show that the proposed algorithm is the most cost-effective ESS operation scheme among the strategies and reduces around 5 percent of electric charges compared to the charge without ESS operation.

Linear Programming based Optimal Scheduling for Grid-connected Microgrid (선형계획법에 의한 계통연계형 마이크로그리드의 최적 운용에 관한 연구)

  • Park, Jae-Sae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.8
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    • pp.1622-1626
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    • 2011
  • Recently, interests on microgrids have been growing as clean power systems. Microgrids include small scaled distributed generation such as wind and solar power as well as diesel generators as main power sources. To operate a microgrid effectively, optimal scheduling for the microgrid is important. Especially, in the grid-connected mode, power trades between the microgrid and the power grid should be considered in optimal scheduling. In this paper, mathematic models for optimal operation of a microgrid were established based on the linear programming. In particular, the shiftable load was considered in the models to optimize it in microgrid operation. To show feasibility of the proposed models, they were applied to optimal microgrid operation and the results were discussed.

Estimation of Optimal Operation Conditions in Step Feed Processes Based on Stoichiometric Nitrogen Removal Reactions

  • Lee, Byung-Dae
    • Journal of the Korean Applied Science and Technology
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    • v.28 no.1
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    • pp.6-9
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    • 2011
  • Step feed process was analyzed stoichiometrically for the optimal operation conditions in this study. In case of optimal operation conditions, minimum R (sludge recycling) value, r (internal recycling ratio) value, and n (influent allocation ratio) value for the step feed process to acquire the maximum TN removal efficiency were identified by theoretical analysis. Maximum TN removal efficiency, based on stoichiometric reaction, can be obtained by controlling n value for the step feed process.

A Study on the Optimal Planning for Dispersed Fuel Cell Generation Systems in Power Systems (전력계통에 있어서 분산형 연료전지 발전시스템의 최적 도입계획에 관한 연구)

  • Rho, Dae-Seok;Shim, Hun;Oh, Yong-Taek;Choi, Jae-Seok;Cha, Jun-Min
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.50 no.6
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    • pp.265-274
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    • 2001
  • Recently, the operation of power systems has become more difficult because the peak demand load is increasing continuously and the daily load factor is getting worse and worse. Also, the consideration of deregulation and global environment in electric power industry is required. In order to overcome those problems, a study on the planning and operation in power systems of dispersed generating sources such as fuel cell systems, photovoltaic systems and wind power systems, has been performed energetically. This paper presents a method for determining an optimal operation strategy of dispersed co-generating sources, especially fuel cell generation systems, considering thermal supply as well as electric power supply. In other words, the optimal operation of those sources can be determined easily by the principle of equal incremental fuel cost and the thermal merit of those sources can be also evaluated quantitatively through Kuhn-Tucker's optimal conditions. In additions, an priority method using the comparison of total cost at the peak load time interval is presented in order ot select the optimal locations of those sources. The validity of the proposed algorithms is demonstrated using a model system.

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The Realization of Optimal Control Operation of a Hybrid Electric Vehicle using Neural Network and the Cruise HEV Simulator (최적 제어와 신경회로망을 이용한 하이브리드 전기자동차 시뮬레이션)

  • Kim, Nam-Wook;Ahn, Kuk-Hyun;Cho, Sung-Tae;Lim, Won-Sik;Lee, Jang-Moo
    • 한국신재생에너지학회:학술대회논문집
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    • pp.349-352
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    • 2005
  • The energy management of an HEV using optimal control and global optimization is thought to be closest to the best operation of the system. However, there are some controversies on the ways of defining the optimization problems and constituting the optimal control simulators. Here, we presented a simulator which adopts the concept of equivalent fuel economy and leads the vehicle to run in a more efficient way. In order to realize the optimal operation of the HEV and check the validity of the control logics, we also developed a forward-facing simulator. The simulator was developed with the Cruise and MATLAB co-simulation interface. Especially, neural network controller was used for the hybrid control module in the simulator. With the simulator, the optimal operation could be converted into hybrid control rules and the validity of the operation was verified.

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Nodal Price Calculation and Decomposition Algorithm Using Voltage State Variable at Non-Optimal Power System Operation (전압상태변수에 의한 비최적 운용계통에 대한 모선가격산정 및 분해 알고리즘의 개발)

  • Kim, Yong-Ha;Lee, Buhm;Choi, Sang-Kyu;Na, In-Kyu;Cho, Sung-Rin;Lee, Sung-Jun;Kim, Dong-Keun
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.5
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    • pp.30-38
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    • 2005
  • This paper proposes a new method which can calculates nodal price as an economic signal at non-optimal operation. By using pseudo constraints in 11 cases, we calculate shadow price and nodal price based on non-optimal operation. By comparing shadow price and nodal prices based on optimal and non-optimal operation effectiveness of the method is verified.