• Korean System Dynamics Review
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• v.5 no.1
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• pp.49-71
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• 2004

Demand-side Management can be defined as'any utility activity aimed at modifying customers' use of energy to produce desired changes in the utility's load shape'. Customers benefit by being able to control energy costs and improve quality of life and become more productive. Utilities benefit from DSM's value as a resource that enhances asset utilization and reduces both fuel costs and environmental emissions. The scope of DSM includes load management through rate schedules and conservation by improving energy effciency and using electricity consumption effectively. This paper study the DSM resource evaluation and customer behavior analysis todesign the DSM Program plan in response to customer needs. We develop basic system dynamics model to analysis the customer behavior based on a survey research. The DSM Program participants in the Hi- efficiency Inverter, Electric motor and efficient lighting applicancies operating by Conservation program 2002 become the survey objects. DSM resource evaluation evaluate firstt the distribution potentialities of each machine and then forecast the degree of diffusion. We apply the system dynamic approach to simulate the dynamic DSM market situation at the domestic beginning. This model will give the energy Planner the opportunity to create different scenarios for DSM program planning. Also it will lead to increased understanding of the dynamic DSM market

• Transactions on Electrical and Electronic Materials
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• v.18 no.6
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• pp.350-358
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• 2017

Recently, owing to increased interest in low-carbon energy supplies, renewable energy sources such as photovoltaics and wind turbines in distribution networks have received considerable attention for generating clean and unlimited energy. The presence of energy storage systems (ESSs) in the promising field of active distribution networks (ADNs) would have direct impact on power system problems such as encountered in probabilistic distributed generation (DG) model studies. Hence, the optimal procedure is offered herein, in which the simultaneous placement of an ESS, photovoltaic-based DG, and wind turbine-based DG in an ADN is taken into account. The main goal of this paper is to maximize the net present value of the loss reduction benefit by considering the price of electricity for each load state. The proposed framework consists of a scenario tree method for covering the existing uncertainties in the distribution network's load demand as well as DG. The collected results verify the considerable effect of concurrent installation of probabilistic DG models and an ESS in defining the optimum site of DG and the ESS and they demonstrate that the optimum operation of an ESS in the ADN is consequently related to the highest value of the loss reduction benefit in long-term planning as well. The results obtained are encouraging.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.979-986
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• 2016

At present, electric power industry around the world are being gradually changed to a new paradigm, such as electrical energy storage system, the wireless power transmission. Demand for ESS, the core technology of the new paradigm, has been growing worldwide. However, it is essential to estimate the optimal capacity of ESS facilities for frequency regulation because the benefit would be saturated in accordance with the investment moment and the increase of total invested capacity of ESS facilities. Hence, in this paper, the annual optimal mathematical investment model is proposed to estimate the optimal capacity and to establish investment plan of ESS facility for frequency regulation. The optimal mathematical investment model is newly established for each season, because the construction period is short and the operation effect for the load by seasons is different unlike previous the mathematical investment model. Additionally, the marginal operating cost is found by new mathematical operation model considering no-load cost and start-up cost as step functions improving the previous mathematical operation model. ESS optimal capacity is established by use value in use iterative methods. In this case, ESS facilities cost is used in terms of the value of the beginning of the year.

• KIEAE Journal
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• v.4 no.2
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• pp.65-72
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• 2004

Ecological architecture enables people to recycle and reuse architectural resources within the category of ecosystem and also to minimize the effect on environment in a whole process, including architectural planning, usage and exhaustion to use sustainable energies. Rammed earth wall construction method utilized in EcoCenter located in Crystalwaters ecological village in Austrailia is a good example, which maximizes its advantages and also covers its limits to use soil and wood as structural resources. In a case of wood, they used non-treated timber to minimize environmental load and utilized used materials in openings. In the roofs, aluminum coated steel which is plated with zinc collects rain effectively even though it is not regenerable. Nontoxic finishes and insulation in floor and ceiling with used papers are able to minimize its environmental load. Solar energy system applied in EcoCenter enables them to market extra energy with electricity companies as well as support needs of its own buildings to utilize photovoltaic panel system with PV panels. Passive solar system is planned effectively in heating and cooling to apply regenerative walls in a use of rammed earth wall construction and natural ventilation systems through openings.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.3-32
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• 2008

The potential deep geothermal resources span a wide range of heat sources from the earth, including not only the more easily developed, currently economic hydrothermal resources; but also the earth's deeper, stored thermal energy, which is present anywhere. At shallow depths of 3,000~10,000m, the coincidence of substantial amounts heat in hot rock, fluids that heat up while flowing through the rock and permeability of connected fractures can result in natural hot water reservoirs. Although conventional hydrothermal resources which contain sufficient fluids at high temperatures and geo-pressures are used effectively for both electric and nonelectric applications in the world, they are somewhat limited in their location and ultimate potential for supplying electricity. A large portion of the world's geothermal resource base consists of hot dry rock(HDR) with limited permeability and porosity, an inadquate recharge of fluids and/or insufficient water for heat transport. An alternative known as engineered or enhanced geothermal systems(EGS), to dependence on naturally occurring hydrothermal reservoirs involves human intervention to engineer hydrothermal reservoirs in hot rocks for commercial use. Therefore EGS resources are with enormous potential for primary energy recovery using an engineered heat mining technology, which is designed to extract and utilize the earth's stored inexthermal energy. Because EGS resources have a large potential for the long term, United States focused his effort to provide 100GW of 24-hour-a-day base load electric-generating capacity by 2050.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.4
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• pp.364-371
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• 2005

Fuel cell systems(FCS) have a financial and environmental advantage by providing electricity at a high efficiency and useful heat. For use in a residence, a polymer electrolyte fuel cell system(PEFCS) with a battery pack and a hot water storage tank has been modelled and simulated. The system is operated without connection to grid line. Its electric conversion efficiency and heat recovery performance are highly dependent on operation strategies and also on the seasonal thermal and electric load pattern. The output of the fuel cell is controlled stepwise as a function of the state of the battery and/or the storage water tank. In this study various operation strategies for cogeneration fuel cell systems are investigated. Average fuel saving rates at different seasons are calculated to find proper load management strategy. The scheme can be used to determine the optimal operating strategies of PEFCS for residential and building applications.

• Structural Engineering and Mechanics
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• v.62 no.4
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• pp.465-475
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• 2017

Photovoltaic (PV) panels are used in high-rise buildings to convert solar energy to electricity. Due to the considerable energy consumption of high-rise buildings, applying PV technology is of great significance to energy saving. In the application of PV panels, one of the most important construction issues is the connection of the PV panel with the main structures. One major difficulty of the connection design is that the PV panel connection consists of two separate components with coupling and indeterminate dimension. In this paper, the gap element is employed in these two separated but coupled components, i.e., hook and catch. Topology optimization is applied to optimize and design the cross-section of the PV panel connection. Pareto optimization is conducted to operate the optimization subject to multiple load scenarios. The initial design for the topology optimization is determined by the common design specified by the Technical Code for Glass Curtain Wall Engineering (JGJ 102-2003). Gravity and wind load scenarios are considered for the optimization and numerical analysis. Post analysis is conducted for the optimal design obtained by the topology optimization due to the manufactory requirements. Generally, compared with the conventional design, the optimized connector reduces material use with improved structural characteristics.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.6
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• pp.880-885
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• 2009

The ships have a lot of electric machinery needed to supply electricity from the moment of launching coming out of dry dock to docking at jetty. Thus, the ships always have to use alternator and electric machinery that has low efficiency under the low load. Many government service ships like the MMU training ship have been spending lots of time at jetty rather than sailing at sea. These ships are operated under the condition of low load due to the operation of basic machinery at jetty and electric machineries are driven with the status of low efficiency. This paper would suggest the energy saving method for these ships. The investigation describes that shore connection is a great asset to these ships and that the flow rate control by adjusting revolution with the adoption of inverter is better than flow rate control by using throttle valve to save energy. The result is based on the investigation of cooling pump at MMU training ship.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.2 s.257
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• pp.253-259
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• 2007

A new material tester has been developed to measure mechanical properties of thin film specimens at high temperature. It is useful for observing oxide film growth or local deformation on the surface, and for measuring creep strength. Main characteristics of the tester is as follows; First, high temperature is achieved by Joule heating generated by electricity passing through the specimen, which does not need to enclose the specimen by a furnace or a heating chamber. The exposed specimen enables one to observe the surface during the test. Because the overall size of the test rig is compact, the whole test rig can be placed in a chamber for environmental controlled tests. The loading device is from a level scales. Not only static load with fixed counter weight, but also variable load by moving counter weight controlled remotely can be applied for an ordinary creep test and creep-fatigue test, respectively. The detail of the construction, operation principle, and the specification are described. And also, an example of test result obtained using the creep tester is presented.

• International Journal of Air-Conditioning and Refrigeration
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• v.11 no.4
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• pp.209-217
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• 2003

The term “energy saving is economical” is appropriate for the national view point and for design and assessment of one system, but not appropriate when choosing the system by comparing alternative systems in the early design step. Sometimes, non-energy saving system is more economical than energy saving system because of the price of electricity, gas or oil, which are used for operating the air conditioning system. Therefore, when designing a system, we should consider the efficient alternatives through economic assessment of energy saving method. However, research on non-operating number control of the system is not sufficient because it is more common to use operating number control of the system for most economic assessment of air conditioning systems. For this reason, this research can provide the economic operating number control method as basic design data. The data obtained through analysis of life cycle cost based on amount of yearly energy use, are produced by system simulation of HASP/ACLD/8501 and HASP/ACSS/8502 for six alternative heating$.$cooling systems based on seasonal air conditioning system, which is widely used for medium and large size office buildings in Busan.