• 설비공학논문집
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• 제14권10호
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• pp.854-862
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• 2002

In the previous research, a simplified correlation method was developed as an easy prediction tool for comparing energy use of cooling plants. The purpose of this paper is to test the applicability of this method for economic evaluation with two zones of a 20-story commercial building in Seoul. The results of this method were compared with the DOE-2 simulation and actual measured data. Then, Comparisons of life cycle cost were carried out for three types of cooling plants. Testing of one zone showed good agreement of within 10% error in cooling energy use and within 2% error in LCC. But testing of the other zone indicated that the use of this method were invalid when input variables were used beyond its valid range.

• 설비공학논문집
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• 제14권5호
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• pp.377-384
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• 2002

For economic evaluation of cooling plant equipments, it is necessary to simplify energy Prediction method, which should includes efficiency corrected by part-load ratio. This study proposed simplified method with regression equations of time-average partial loads and refrigerator capacity. DOE-2 Program was used to carry out a parametric study of twelve design variables. Five input variables were considered to be significant and were used in the regression equations. To test accuracy of simplified method, calculated results were compared with DOE-2 simulated results. Test result showes a good agreement with the simulation result with an error of 5.9∼7.6%. It is expected that this method can be used as an easy prediction tool for comparing energy use of different cooling plants during the early design stage.

• Nuclear Engineering and Technology
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• 제36권6호
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• pp.571-581
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• 2004

A methodology is proposed for the evaluation of a steam explosion load on a reactor scale by evaluating the steam explosion model against the experimental data. Being part of the OECD/SERENA program,, appropriate data was selected by international experts and the analytical model of TEXAS-V was chosen. The procedure consists of two steps. the pre-mixing model was verified against the FARO L-14 and FARO L-28 data. The explosion model was verified against the experimental data of KROTOS-44, FARO L-33, TROI-13, and TROI-34. The capabilities and deficiencies of the fundamental models of the TEXAS-V are reviewed in terms of their adequacy in a simulation of steam explosion on a reactor scale.

• KIEAE Journal
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• 제13권1호
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• pp.39-45
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• 2013

The daylighting control system has to be applied to prevent the excessive incident daylight and reduce energy use. As the one of the most useful daylighting control systems, the blind system is simple and easy to install on the window for small office buildings. This study aims to evaluate the summer energy performance of small office buildings by venetian blinds and energy saving strategy of ministry of knowledge economy in korea. For the study, the simulations have been executed on blind installation conditions and lighting control methods. As results, the energy loads cut down 22 to 25(%) by using blind energy. Also, the efficient shows high on EMS system and low on $45^{\circ}$ slat angles. Also, using energy saving strategy can reduce about 13(%) energy load.

• 한국태양에너지학회 논문집
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• 제28권6호
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• pp.40-47
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• 2008

The importance for energy consumptions has being emphasized because of problems of the energy and environment. Especially, education buildings among public buildings which have being emphasized the application of environment-friendly elements because of large energy consumptions. Accordingly, this study established parameters of green walls and green roofs which have ecological effects and energy savings. And then this study analyzed indoor thermal environments and energy consumptions due to green walls and green roofs through the energy simulation(Visual DOE 4.0) and the actual measurement.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권8호
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• pp.1805-1824
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• 2013

Recently, the use of wireless body area networks (WBAN) has been increasing rapidly in medical healthcare applications. WBANs consist of smart nodes that can be used to sense and transmit vital data such as heart rate, temperature and ECG from a human body to a medical centre. WBANs depend on limited resources such as energy and bandwidth. In order to utilise these resources efficiently, a very well organized medium access control (MAC) protocol must be considered. In this paper, a new, adaptive and energy-efficient MAC protocol, entitled isMAC, is proposed for WBANs. The proposed MAC is based on multi-channel communication and aims to prolong the network lifetime by effectively employing (i) a collision prevention mechanism, (ii) a coordinator node (WCN) selection algorithm and (iii) a transmission power adjustment approach. The isMAC protocol has been developed and modelled, by using OPNET Modeler simulation software. It is based on a networking scenario that requires especially high data rates such as ECG, for performance evaluation purposes. Packet delay, network throughput and energy consumption have been chosen as performance metrics. The comparison between the simulation results of isMAC and classical IEEE 802.15.4 (ZigBee) protocol shows that isMAC significantly outperforms IEEE 802.15.4 in terms of packet delay, throughput and energy consumption.

• Nuclear Engineering and Technology
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• 제33권2호
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• pp.209-224
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• 2001

The SSC-K system analysis code is under development at the Korea Atomic Energy Research Institute (KAERI) as a part of the KALIMER project. The SSC-K code is being used as the principal tool for analyzing a variety of off-normal conditions or accidents of the preliminary KALIMER design. The SSC-K code features a multiple-channel core representation coupled with a point kinetics model with reactivity feedback. It provides a detailed, one-dimensional thermal-hydraulic simulation of the primary and secondary sodium coolant circuits, as well as the balance-of-plant steam/water circuit. Recently a two-dimensional hot pool model was incorporated into SSC-K for analysis of thermal stratification phenomena in the hot pool. In addition, SSC-K contains detailed models for the passive decay heat removal system and a generalized plant control system. The SSC-K code has also been applied to the computational engine for an interactive simulation of the KALIMER plant. This paper presents an overview of the recent activities concerned with SSC-K code model development This paper focuses on both descriptions of the newly adopted thermal hydraulic and neutronic models, and applications to KALIMER analyses for typical anticipated transients without scram.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.506-519
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• 2024

To simulate the verification process using materials from a decommissioned reactor, a mock-up of the bottom-mounted instrument nozzle in the Kori 1 reactor, where the nozzle was attached to a plate by J-groove dissimilar metal welding, was fabricated. The mock-up distortion was quantified by measuring the plate surface displacement after welding. The residual stresses formed on the support plate surface and the inner surface of the nozzle were then analyzed using the hole-drilling method, contour method, and neutron diffraction. Welding simulations were performed using a 3D finite element method to validate the measured results. The measured and computed stress distributions on the support plate exhibited reasonable agreement. Conversely, the stresses on the inside of the nozzle were found to have an indisputable difference in the contour method and neutron diffraction measurements, which demonstrated strong tensile and compressive hoop stresses, respectively. The possible origins of such differences were investigated and we have provided some suggestions for a precise evaluation in the simulation. This study is expected to be useful in future research on decommissioned reactors.

• 조명전기설비학회논문지
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• 제28권12호
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• pp.55-64
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• 2014

This paper presents a case study to investigate the monthly calculation method of ISO 13790 applied for a office building. The energy performance analysis according to improvement of insulation and air permeability of windows in K office buildings is investigated by means of building energy efficiency rating tool ($ECO_2-OD$). The K building energy system is tested experimently by the measurement of PMV(predicted mean vote) for the control of indoor thermal environment and heat transmission coefficient of windows and interior walls respectively, before and after the example K office building is remodeled passively. Therefore, Internet based energy assessment program of energy efficiency rating of office building can be applied as a program for the annual energy requirement and for evaluation of energy savings from the experimental and simulation results.

• 설비공학논문집
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• 제26권4호
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• pp.145-150
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• 2014

Many studies are being conducted with the aim of reducing the energy consumption in data centers, which are one of the highest consumers of energy. The use of an air-side economizer system that uses external air during intermediate and winter seasons is being considered for reducing the energy consumption of air conditioners. In this study, using the energy simulation, we evaluated the energy performance of a central chilled water cooling system and air-side economizer system in domestic data centers. Further, the cost-effectiveness of the air-side economizer was analyzed through Life-Cycle Cost Analysis. The results showed that with the use of air-side economizer systems, the energy costs increased as the applied filter grade increased; however, unlike existing central chilled water systems, it would break even within 2 years.