• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.325-331
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• 2009

In this paper, a simulation approach for the optimum design of cogeneration system is described. For the purpose of the systematic analysis, a simulation tool is developed with which the prediction of the energy load, calculation of operation data according to prime mover or capacity of it, and estimation of economic gains can be carried out. As for the criterion of the optimum design, the economic gains by adopting cogeneration system is taken. Based on the capital, operation, and maintenance costs etc, LCC analysis is to be carried out for the scenarios respectively. In this study, the simulation for the apartment complex is performed and the analysis of the results are described in detail. The effects of the operation parameters such as capital cost, fuel cost, and unit cost for the purchase or sale of heat and electricity on overall economy are also be considered by sensitivity study.

• Plant Journal
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• v.7 no.2
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• pp.44-51
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• 2011

Given the fact that the entire bituminous coal used for a boiler is imported, the supply of coal is often affected by the rise of international coal price. Moreover, coal suppliers have been diversified due to the competition among power generation companies for reducing costs and inexpensive sub-bituminous coal is used. As a result, boilers combustion conditions have been deviated from the initial boiler design. This requires the selection of adequate excessive air ratio for different combustion conditions to enhance the efficiency of boiler operation. The boiler efficiency has been identified through an examination on the change of excessive air ratio by mixed fuel in unit 8 of Dangjin power plant complex. In addition, an excessive air ratio was calculated based on the examination result. According to the study result, the adequate excessive air ratio was 13% when Macquarie and Powder river were mixed at a ratio of 5:5 and when Sonoma and Megaprima persada were mixed at a ratio of 5:5. When BHP Billiton and Powder river were mixed at a ratio of 4:6 and Centennial and Batubara were mixed at a ratio of 3:7, the adequate excessive air ratio was 11%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.367-368
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• 2012

In resent years, engineering thermoplastics represent a means for designers to integrate parts, facilitate assembly, reduce weight and lower the costs of their parts to improve the fuel efficiency and competitiveness of the cars. Thermoplastic turbo charger intake hose is one of most sophisticated application in thermoplastics under the hood. Used as part of weight & cost reduction and performance improvement program, thermoplastic turbo charger intake hose has been developed as rubber and metal replacement. For optimized product, NVH performance is a important criteria while keeping same durability required with current system. Though a number of studies have been conducted on the resonator hose and its analytical models, the most of studies were focused on transmission loss itself. This paper presents contribution of vehicle interior noise according to design parameters like profile, bellows type, bellows position, material characteristic. And we will review the design guidance for optimized product of thermoplastic turbo charger intake hose.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.3
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• pp.135-150
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• 2012

This paper presents a portfolio model for a long-term power generation mix problem. The proposed portfolio model evaluates generation mix by considering the tradeoffs between the expected cost for power generation and its variability. Unlike conventional portfolio models measuring variance, we introduce Conditional Value-at-Risk (CVaR) in designing the variability with aims to considering events that are enormously expensive but are rare such as nuclear power plant accidents. Further, we consider uncertainties associated with future electricity demand, fuel prices and their correlations, and capital costs for power plant investments. To obtain an objective generation by each energy source, we employ the sample average approximation method that approximates the stochastic objective function by taking the average of large sample values so that provides asymptotic convergence of optimal solutions. In addition, the method includes Monte Carlo simulation techniques in generating random samples from multivariate distributions. Applications of the proposed model and method are demonstrated through a case study of an electricity industry with nuclear, coal, oil (OCGT), and LNG (CCGT) in South Korea.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.530-537
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• 2010

By development of renewable energy and more efficient facilities in an increasingly deregulated electricity market, the operation cost of distributed generation (DG) is becoming more competitive. International environmental regulations of the leaking carbon become effective to reinforce global efforts for a low-carbon paradigm. Through increased DG, operators of DG are able to supply electric power to customers who are connected directly to DG as well as loads that are connected to entire network. In this situation, a community energy system (CES) with DGs is a new participant in the energy market. DG's purchase price from the market is different from the DG's sales price to the market due to transmission service charges and other costs. Therefore, CES who owns DGs has to control the produced electric power per hourly period in order to maximize profit. Considering the international environment regulations, CE will be an important element to decide the marginal cost of generators as well as the classified fuel unit cost and unit's efficiency. This paper introduces the optimal operation of CES's DG connected to the distribution network considering CE. The purpose of optimization is to maximize the profit of CES. A Particle Swarm Optimization (PSO) will be used to solve this complicated problem. The optimal operation of DG represented in this paper would guide CES and system operators in determining the decision making criteria.

• Journal of Power Electronics
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• v.11 no.4
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• pp.393-400
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• 2011

The main objective of this paper is to control the speed of Nonlinear Hybrid Electric Vehicle (HEV) by controlling the throttle position. Various control techniques such as well known Proportional-Integral-Derivative (PID) controller in conjunction with state feedback controller (SFC) such as Pole Placement Technique (PPT), Observer Based Controller (OBC) and Linear Quadratic Regulator (LQR) Controller are designed. Some Intelligent control techniques e.g. fuzzy logic PD, Fuzzy logic PI along with Adaptive Controller such as Self Organizing Controller (SOC) is also designed. The design objective in this research paper is to provide smooth throttle movement, zero steady-state speed error, and to maintain a Selected Vehicle (SV) speed. A comparative study is carried out in order to identify the superiority of optimal control technique so as to get improved fuel economy, reduced pollution, improved driving safety and reduced manufacturing costs.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.6
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• pp.305-311
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• 2000

This paper presents a hybrid algorithm for solving optimal power flow(OPF) in order to enhance a systems capability to cope with outages, which is based on combined application of evolutionary computation and local search method. The efficient algorithm combining main advantages of two methods is as follows : Firstly, evolutionary computation is used to perform global exploitation among a population. This gives a good initial point of conventional method. Then, local methods are used to perform local exploitation. The hybrid approach often outperforms either method operating alone and reduces the total computation time. The objective function of the security constrained OPF is the minimization of generation fuel costs and real power losses. The resulting optimal operating point has to be feasible after outages such as any single line outage(respect of voltage magnitude, reactive power generation and power flow limits). In OPF considering security, the outages are selected by contingency ranking method(contingency screening model). The OPF considering security, the outages are selected by contingency ranking method(contingency screening model). The method proposed is applied to IEEE 30 buses system to show its effectiveness.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.305-320
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• 2016

The metal waste generated during nuclear power plant decommissioning constitutes a large proportion of the total radioactive waste. This study investigates the current status of domestic and international regulatory requirements for clearance and the clearance experience of domestic institutions. The RESRAD-RECYCLE code was used for analyzing the clearance of the metal wastes generated during actual nuclear power plant decommissioning, and assessment of the exposure dose of twenty-six scenarios was carried out. The evaluation results will be useful in preliminary analysis of clearance and recycling during nuclear power plant decommissioning. As a next step, the effects of reducing disposal costs by clearance can be studied.

• Environmental and Resource Economics Review
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• v.17 no.1
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• pp.23-49
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• 2008

In this paper, we estimate whether changes in the economic environment a firm operates in affects technical efficiency. Since efficiency gains can manifest themselves in a variety of ways, we estimate for efficiency gains on annual generating plants input demand for expenses and fuel use. We find that generating plants reduced their workers and costs respectively by 6.8% in 1999 and 37.9% in 2001. However, they didn't show any systematic caloric consumption changes facing various economic environmental shocks. These results suggest that restructuring brought efficiency gains by replacing regulated monopoly with a more competitive firms in the context of the Korean electricity market.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.4
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• pp.385-391
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• 2006

The estimated decommissioning cost of nuclear research reactor is calculated by applying a unit cost factor-based engineering cost calculation method on which classification of decommissioning works fitted with the features and specifications of decommissioning objects and establishment of composition factors are based. Decommissioning cost of nuclear research reactor is composed of labor cost, equipment and materials cost. Labor cost of decommissioning costs in decommissioning works are calculated on the basis of working time consumed in decommissioning objects. In this paper, the unit cost factors and work difficulty factors which are needed to calculate the labor cost in estimating decommissioning cost of nuclear research reactor are derived and figured out.