• Title/Summary/Keyword: 환기 시뮬레이션

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Optical Switching Architectures using WDM for High-Speed ATM Networks (고속 ATM망을 위한 파장 분할 광교환기 구조)

  • So, W.H.;Lee, C.H.;Kim, Y.S.;Kim, Y.C.
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.8
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    • pp.12-20
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    • 1998
  • All-optical networks(AON) are emerging as the next generation broadband networks for wide-area and local-area networks. Many optical switch architectures are currently proposed to realize AON. Specially, optical switches using WDM have a lot of advantages in point of the optical transparency and network topology for B-ISDN services in AON. In this paper, two kinds of Knockout Optical Switching Architectures(KOSA) are proposed for high speed optical ATM networks. We use WDM technologies for them to operate in all-optical area and they are called Architecture-Ⅰ, Architecture-Ⅱ respectively. Each one represents different characteristics according to the number of components and the kind of components, which make KOSA have different performance and system complextity. In order to verify and to compare the performance, these architectures were analyzed and simulated in terms of cell loss ratio, system complexity and buffering speed.

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A study of Heat & Smoke Extraction Effects by the Various Operation of funnel Fan Shaft Ventilation (터널팬 샤프트 환기 방식에 따른 열 및 연기배출효과에 관한 연구)

  • Rie, Dong-Ho;Yoo, Ji-Oh
    • Fire Science and Engineering
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    • v.18 no.2
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    • pp.49-56
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    • 2004
  • Today's popular ventilation systems include the combined jet fans and electrostatic precipitation systems or the combined jet fans and vertical shaft system. Tunnels with these two ventilation systems applied have been designed and opened, more and more interest has been put in maintenance of a tunnel after opening. Therefore. it is to become more important to come up with the optimal operation mode and the method for the evaluation of ventilation system. In this study, to evaluate a tunnel ventilation and its economy, a dynamic simulation program was developed which can simulate the unsteady-state tunnel air velocity and concentration of pollutants according to the traffic flow variations and operation condition of a ventilation system. We clarified the effectiveness usage on tunnel ventilation by using it and also we could found the most economical ventilation operation mode by application in real exit tunnel. We obtained that combination of fan system and electrostatic precipitation system was more economical than jet fan priority operation mode.

A Comparison of Performance on the Orthogonal and Refraction Heat Exchanger Shape in Air Ventilation System (환기시스템의 굴절 및 평판형 열교환기 형상에 따른 성능비교)

  • Hyeon, Hyeong-Ho;Jeong, Byeong-Ho;Kim, Ji-won;Lee, Kang-yeon
    • Journal of the Korea Convergence Society
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    • v.10 no.7
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    • pp.281-287
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    • 2019
  • Application of heat recovery system applying air supply and cexhaust ventilation device essential in energy management system for the optimum ventilation system utilization and energy saving. This is a key element of infrastructure technology for high-efficiency energy buildings, because it can save heating and cooling energy in winter and summer. In this paper, heat transfer efficiency was simulated using paper, plastic, and aluminum materials that was examined to compare heat exchanger performance under uniform flow conditions. We tested heat transfer efficiengy according to the shape of two of that, one is orthogonal and the other is refraction shape. Based on the simulation results, it is expected to contribute to the production of high performance heat exchanger with heat transfer performance and pressure loss.

A Study on Improvement of the Roof Vents in the Arcade Traditional Market (아케이드형 재래시장의 지붕 환기구 개선 방안에 관한 연구)

  • Ma, Jun Chao;Lee, Byung Hyun;Lee, Kyung Hee
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.30 no.1
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    • pp.17-23
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    • 2018
  • A fire simulation was performed to analyze the temperature and smoke exhaust performance of roof vents of the arcade traditional market by comparing a basic model (Case A) and an improvement model (Case B~Case E). Temperature analysis by heat showed a low temperature distribution because Case E discharged smoke in both directions of length compared to other cases. However, the effect of heat by life safety standards was satisfied. The smoke exhaust analysis by smoke showed the highest performance because Case C was exhausted to 1 m on both sides of length.

Numerical Simulation on Thermal Performence of Passive Ventilation Skin (패시브환기외피의 열성능 수치시뮬레이션)

  • Lee, Tae-Cheol;Son, Yu-Nam;Yoon, Seong-Hwan
    • 한국태양에너지학회:학술대회논문집
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    • 2011.04a
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    • pp.144-149
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    • 2011
  • This study aims to evaluate performance of ventilation and thermal about breathing wall by flowing air to indoor on appropriate conditions that is effective aperture area in the Central region(20, 50, $80cm^2/m^2$). The result is as follows : 1) Sectional temperature distribution of inflow and outflow out under the constant ventilation was reviewed. In the case of inflow, outside temperature increase effect was confirmed. 2) The more differences of temperature between outdoor and indraft of air was high, the more heat recovery was high.

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Verification Experiment and Simulation of Cooling Load for a Test Space with Forced Ventilation (시험공간에 강제환기를 고려한 냉방부하의 실증실험 및 시뮬레이션)

  • Kim, Dong-Hyeok;Yoo, Ho-Seon;Hong, Hi-Ki
    • Proceedings of the SAREK Conference
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    • 2005.11a
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    • pp.217-222
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    • 2005
  • Building energy consumption according to the ventilation has been considered to be an important subject. The purpose of this study is to investigate the cooling loads in a test space with a forced ventilating system. In the test space, on/off controlled air-conditioning and forced ventilating facility were operated between 8:30 to 21:00 during 4 days and some important data like temperatures and energy consumption were measured to obtain actual cooling loads. The simulation was carried out in a mode of temperature level control using a TRNSYS 15.3 with a precisely measured air change amount and performance data of air-conditioner. Cooling loads including sensible and latent were compared between by experiment and by simulation. Both of cooling loads associated with ventilation show a close agreement within an engineering tolerance.

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Fire Simulation Study and Tunnel Ventilation of Requirement in the Longitudinal Tunnel. (In Yimgo-4th Tunnel) (종류식 터널내 소요 환기량에 의한 터널환기 및 화재 시뮬레이션 연구 ( 임고 4 터널 ))

  • Chae, Kyung-Hee
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1378-1385
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    • 2008
  • This study is aimed to analyze the flow patterns and thermal characteristics by computer simulation under the variations of fire strength for Daegu-Pahang Yimgo-4th tunnel, from which flow and heat distributions are predicted in the longitudinal tunnel. Though the results of numerical computations, followings are found; one is that the volume flow rate is discontinuously increasing as closer to fire location, and the other is that a critical design to get faster flow rate is required because of existence of backlayer flow for the high fire strength in view of safety for the people in fire of the tunnel.

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Calibration in Hybrid Ventilation Simulation: yes or no? (하이브리드 환기 시뮬레이션 모델의 보정: yes or no?)

  • Kim, Young-Jin;Park, Cheol-Soo
    • 한국태양에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.130-135
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    • 2009
  • This study investigates the need of calibrating a nodal network ventilation simulation model (CONTAMW 2.4). For this purpose, the series of ventilation experiments were conducted and then compared to simulation outputs from an uncalibrated simulation model, resulting in a significant difference between two. Hence, an optimization routine was employed to estimate unknown parameters in the simulation model. In the paper, the authors presents 1.3 unknown parameters with the validated simulation model. It was found that the model with estimated unknown parameters predicts the ventilation phenomena accurately.

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Predictive Model of Micro-Environment in a Naturally Ventilated Greenhouse for a Model-Based Control Approach (자연 환기식 온실의 모델 기반 환기 제어를 위한 미기상 환경 예측 모형)

  • Hong, Se-Woon;Lee, In-Bok
    • Journal of Bio-Environment Control
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    • v.23 no.3
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    • pp.181-191
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    • 2014
  • Modern commercial greenhouse requires the use of advanced climate control system to improve crop production and to reduce energy consumption. As an alternative to classical sensor-based control method, this paper introduces a model-based control method that consists of two models: the predictive model and the evaluation model. As a first step, this paper presents straightforward models to predict the effect of natural ventilation in a greenhouse according to meteorological factors, such as outdoor air temperature, soil temperature, solar radiation and mean wind speed, and structural factor, opening rate of roof ventilators. A multiple regression analysis was conducted to develop the predictive models on the basis of data obtained by computational fluid dynamics (CFD) simulations. The output of the models are air temperature drops due to ventilation at 9 sub-volumes in the greenhouse and individual volumetric ventilation rate through 6 roof ventilators, and showed a good agreement with the CFD-computed results. The resulting predictive models have an advantage of ensuring quick and reasonable predictions and thereby can be used as a part of a real-time model-based control system for a naturally ventilated greenhouse to predict the implications of alternative control operation.

The Study on the Design and Implementation of SHF band Downconverter of Digital Satellite Communication (디지털위성중계기용 SHF 대역 하향주파수 변환장치 설계 및 구현에 대한 연구)

  • Kim, Ki-Jung
    • The Journal of the Korea institute of electronic communication sciences
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    • v.12 no.3
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    • pp.427-432
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    • 2017
  • This study describes the design and implementation of SHF band Downconverter Digital Satellite Communication. The SHF band Downconverter unit consists of PLDRO and Frequency converter. In Frequency converter, microstrip BPF and LPF designed through the pre EM simulation are implemented to minimize the unwanted spurious in Frequency converter. Through the pre-simulation analysis of space environment, the possibility of and minimized about the malfunction of equipment and we designed a reliable SHF band Downconverter through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of SHF band Downconverter after production.