• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.3
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• pp.415-425
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• 1996

This study presents an analytical method of solving the behaviors of arc plasma in a nozzle constricting transferred-type torch and purposes to obtain the basic data for the design of a plasma torch, which can be obtained from the temperature, pressure, velocities and voltage distributions. We have to solve some conservation equations simultaneously and need to know the exact thermal gas properties in order to obtain the correct behaviors of arc plasma. It is also necessary to give the relevant physical or geometric boundary conditions. For the simplicity of analysis, we assumed that (a) the plasma flow is laminar, (b)the local thermodynamic equilibrium, i.e. LTE, prevails over the entire arc column region. The electrode sheath effects were neglected and the nozzle area was excluded from the analysis by assuming that the current flow into the nozzle is zero. We solved the momentum transfer equation including the self-magnetic pinch effect, and obtained the temperature distribution from the energy conservation equation. From this temperature, we could get arc voltage distribution. (author). refs., figs., tabs.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.903-908
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• 2006

Building energy simulation has become a useful tool for predicting cooling, heating and air-conditioning loads for facilities. It is important to provide building energy performances feed back to the mechanical and electrical system operator and engineer for energy conservation and maintenance of building. From this research, we set up the typical weather data of location, basic description of building, geometric modelling data and the specification of Installed primary HVAC system for establishing the simulation model about energy consuming that take place in multipurpose building complex. The simulation tool of building energy - EnergyPlus (DOE and BLAST based simulation S/W), it has been used and accomplished calculations and analyses for evaluating the effect of the system types and operating condition of central HVAC plant on the building energy consumption. In this paper, we offer comparison and simultaneous results those involve electricity consumption pattern and amount between actual operation versus EnergyPlus simulation to the object building during summer season.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1689-1696
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• 2017

In this paper, the voltage measurement-based coordinated Voltage/VAR control (VMCVVC) algorithm for conservation voltage reduction(CVR) is proposed. The proposed algorithm has the purpose of enhancing the CVR effect through coordinated control of the voltage control devices such as the distributed energy resources and the load tap changer(LTC) transformers. It calculates the references of the voltage control devices such that the bus voltages are maintained at as close to the lower operation limit as possible. For this purpose, firstly, the distribution system is divided into LTC transformer control zones through topological search. Secondly, the reactive power references of the reactive power control devices are determined such that the voltage profile of the section is flattened. Finally, the tap references of the LTC transformers are calculated to lower the voltage profile. The effectiveness of the proposed algorithm is demonstrated through case studies using IEEE test network.

• KIEAE Journal
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• v.14 no.2
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• pp.11-19
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• 2014

Building energy consumption takes up almost 25% of the total energy consumption. Therefore, diversified ways, such as improving wall and window insulation, have been considered to reduce building energy consumption. Recently, green roof system has been explored as an effective alternative for dealing with reducing heating and cooling energy, thermal island effect and improving water quality. However, recent studies regarding a green roof system have only focused on building energy reduction without considering the applied usage, location, and story of the green roof system. Therefore, this study pays attention to the heating and cooling energy in relation to the applied usage, location, and story of a green roof system for investigating its impact on energy reduction. The result of simulations show that the reduction in heating energy consumption is higher when applied to Cherwon-gun province which has a continental climate condition, compared to the city of Busan that is distinguished by its warm climate. Cooling energy saving turns out to be higher when the green roof system is applied to Busan in comparison with Cherwon. As for the applied usage or function of the building, residential space acquires the highest heating and cooling energy saving effect rather than commerce, educational or office space because of HVAC's running time based on usage. When it comes to the story of the green roof, both heating and cooling energy saving become the highest when the green roof is applied to single-storied buildings. The reason is that single story building is affected by the ground largely. Generally, the variations of heating energy consumption are larger than the cooling energy consumption. The outcome of the simulations, when a green roof system is applied, indicates that the energy consumption reduction rate is dynamically responding to the applied usage, location, and story. Therefore, these factors should be counted closely for maximizing the reduction of energy consumption through green roof systems.

• Journal of Energy Engineering
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• v.8 no.1
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• pp.1-6
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• 1999

사울 지역을 대상으로 TDM 수단의 도입 및 연비 향상대책 등에 의한 에너지절약 효과를 분석한 결과, 승용차의 경우 1) 함께타기 촉진에 의한 승차율이 2% 정도 향상될 경우 서울여객 소비의 3.3%(전국여객 소비의 1.0%), 2) 버스전용차개선제 등의 TDM 수단이 도입.시행에 따라 서울여객 소비의 2.6%(전국여객 소비의 0.8%), 3) 2000년까지 자동차 연비목표치가 달성되면 서울여객 소비의 3.2%(전국여객 소비의 0.9% 상당) 감소하는 등, 이들 모든 시책이 도입되는 경우 서울 여객 소비기준 약 9.1%의 에너지 절약 효과가 기대된다. 화물차의 경우에는 1) 공동배송에 의한 수송 효율화에 따라 적재율이 10% 향상되면 서울화물 소비의 8.9%(전국화물 소비의 1.6%), 2) 또 수송효율에 의한 실차율이 2% 향상되면 서울화물 소비의 1.8%(전국화물 소비의 0.3%), 3) 2000년까지 자동차 연비가 5% 향상되면 서울화물 소비의 1.4%(전국화물 소비의 0.4%) 감소하는 것을 합하면 약 12.1%의 에너지절약효과가 기대된다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.3
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• pp.300-311
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• 1997

A theoretical method was developed to analyze the effect of low-$\varepsilon$ coatings which have influence on thermal performance of vacuum windwo glazing and double pane glazing. The overall heat transfer coefficient(U) value and thermal performance were analyzed by theroretical method on various kins of windows. TRNSYS program was used to analyze total heating and cooling energy consumption on the model building which has various windows. As the result, better thermal insulation can be achieved on the vacuum window glazing than double pane glazing when low-$\varepsilon$ coating was done on the surface of glass. Total heating and cooling energy consumption was almost same on the double pane window glazing but was lessened on the vacuum window glazing when the window size of south direction increased. Therefore, low-$\varepsilon$ coating was very necessary for vacuum window glazing in order to improve thermal insulation performance and efficient energy conservation can be achieved by vacuum window glazing at the real building which has large window.

• Journal of the Korean Institute of Rural Architecture
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• v.5 no.2
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• pp.1-9
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• 2003

Local Agenda 21 insists Local National role for earth environmental preservation. It is effect in earth environment important code that each local government promotos Local Agenda 21. Local agenda requires changes in lifestyle from everyone, such as limiting use of energy.Local agenda is difficult to define. But the goal of agenda development can guide furure policy. In this study, investigated local agenda actural condition and housing present condition, energy consumption. It is analyzed practice item of city and architecture local agenda. It is also proposed data of architecture and presented direction of architecture local agenda.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.51-57
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• 2021

In this paper, the relevance between Einstein's special theory of relativity (1905) and Bernoulli's fluid mechanics (1738), which motivates Shannon's theorem (1948), was derived from the AB=A/A=I dimension, and the Shannon's theorem channel code was simulated. When Bernoulli's fluid mechanics ΔP=pgh was applied to the Hallasan volcano Magma eruption, the dimensions and heights matched the measured values. The relationship between Einstein's special theory of relativity, Shannon's information theory, and the stack effect theory of fluid mechanics was analyzed, and the relationship between volcanic eruptions was mathematically proven. Einstein's and Bernoulli's conservation of energy and conservation of mass were the same in terms of bandwidth and power efficiency in Shannon's theorem.

• Environmental and Resource Economics Review
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• v.22 no.3
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• pp.547-580
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• 2013

As energy conservation can be realized through changes in the composition of goods and services consumed, there is a need to assess indirect and total household energy consumption. The Korean household sector was responsible for more than 55% of Korea's total energy consumption in the 1995 to 2010 period. More than 69% of household energy consumption was indirect. Thus, not only direct but also indirect household energy consumption should be the target of energy conservation. Electricity consumption became in 2009 the main source of household energy consumption in Korea. Households consume more and more electricity intensive goods and services, a sign of increasing living standards. Decrease in energy intensities of products consumed by Korean households contributed greatly to reduce the increase in the total household energy consumption. However, switching took place towards more energy intensive products, thus the structure effect was negative. It is necessary to direct consumption and production towards much less energy intensive goods and services as to reduce energy consumption or its growth rate. The Korean government should readjust low energy and electricity prices to cost-reflective prices levels as these low prices are one of the main reasons for the consumption of more energy intensive products. This study differentiates prices of oil products and electricity between households and industries, as to allow more accurate estimation.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.600-605
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• 2009

A general purpose viscous flow solver Ansys CFX is used to study a Savonius type wave energy converter in a 3D numerical viscous wave tank. This paper presents the results of a computational fluid dynamics (CFD) analysis of the effect of blade configuration on the performance of 3 bladed Savonius rotors for wave energy extraction. A piston-type wave generator was incorporated in the computational domain to generate the desired incident waves. A complete OWC system with a 3-bladed Savonius rotor was modeled in a three dimensional numerical wave tank and the hydrodynamic conversion efficiency was estimated. The flow over the rotors is assumed to be two-dimensional (2D), viscous, turbulent and unsteady. The CFX code is used with a solver of the coupled conservation equations of mass, momentum and energy, with an implicit time scheme and with the adoption of the hexahedral mesh and the moving mesh techniques in areas of moving surfaces. Turbulence is modeled with the k.e model. Simulations were carried out simultaneously for the rotor angle and the helical twist. The results indicate that the developed models are suitable to analyze the water flows both in the chamber and in the turbine. For the turbine, the numerical results of torque were compared for all the cases.