• Title/Summary/Keyword: Ventilation

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Assessment of Clothing Ventilation through Openings (개구부를 통한 의복의 환기 양상 평가)

  • 추미선
    • The Research Journal of the Costume Culture
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    • v.8 no.5
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    • pp.660-667
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    • 2000
  • Clothing ventilation was investigated using a manikin wearing an impermeable overall under an isothermal condition, in which the ventilation occurred only through the openings. The ventilation volume was estimated by both microenvironment volume and ventilation rate, where, the microenvironment volume was measured by an air subsitution method and the ventilation rate by a trace gas method. Microenvironment volume of the experimental garment was about 21.0 liters. Even though it was certainly affected by the distance from the opening, the ventilation rate was more significantly influenced by the opening area and the shape of air layer in the clothing. The volume of air exchange in the clothing microenvironment was affected greatly by the microenvironment volume and the opening area, and it was different for each part of the body with bigger air exchange volume in the microenvironment of the leg as compared to that of the arm.

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Analysis of the Air-flow for Natural Ventilation of Express Bus (고속버스 자연환기구의 기류패턴 분석)

  • Yoo, Ho-Chun;Noh, Kyoung-Hwan
    • 한국태양에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.336-341
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    • 2009
  • In express bus which has no window, the air quality inside the bus is very critical for the passengers who staying for an extended time. Air conditioning system using natural energy is expected to significantly improve the air quality while the bus runs the suburban area. But the express buses today usually attempt to ventilate using air conditioning system, rather than natural ventilation. In this study, analysis of existing ventilation opening and the new ventilation system on roof, using computer simulation. As a result, two cases using existing ventilation device was found to be effective for partial ventilation only, while the air in front remains standstill. The new system proved to have promoted more dynamic ventilation in most of space.

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Analysis on ventilation efficiency by CFD simulation for breathing zone in bed room (CFD해석에 의한 침실 호흡역의 환기효율 분석)

  • Yoo, Bok-Hee;Yoon, Chung-Sook
    • KIEAE Journal
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    • v.2 no.3
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    • pp.11-16
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    • 2002
  • Indoor air environment is one of the most important factors that affect resident's health and comfort level. In this paper, the influence of ventilation efficiency with different types of furniture arrangement at breathing zone in a room was analyzed by numerical simulation based on computational fluid dynamics(CFD). The furniture layout of students' bedroom have been classified by three different patterns so that SVE3(scale for ventilation efficiency3) in the rooms was analyzed for air flow distribution. According to the results of the study, SVE3 has the maximum value in spaces between furnitures and each comer of the room. The furniture arrangement influences the ventilation efficiency. It was con finned that ventilation effective in a room is not uniformly distributed as compared the breathing zone with all the area in a room. It means that a study of ventilation efficiency was considered relatively with target zone(a residential or breathing zone) and all the area in a space.

A Study on the Air Ventilation System in Apartment Houses as a Health Concept - focused on the air ventilation and pilotis - (공동주택에 건강개념인 통기시스템에 관한 연구 - 공기순환과 필로티를 중심으로 -)

  • Cho, Cheul Hee;Lee, Teuk Koo
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.10 no.1
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    • pp.29-38
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    • 2004
  • The purpose of this study is to analyze the air ventilation system in apartment houses focused on the air circulation and pilotis. The air ventilation system is used with the data which were obtained by the environmental health, urban climate, air pollution, ventilation path. The architectural element was pilotis concept connected with piloti ratio, piloti position and piloti type. The summaries of this study were as follows; 1) the well-being apartment concept, 2) the heat island phenomenon, 3) the oxygen density of air, 4) the definition of ventilation path, 5) the pilotis connected with residential environment improvement. In addition, the detailded case study to the air ventilation system in apartment houses be needed.

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Home mechanical ventilation in children with chronic respiratory failure: a narrative review

  • Soyoung Kwak
    • Journal of Yeungnam Medical Science
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    • v.40 no.2
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    • pp.123-135
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    • 2023
  • Advances in perinatal and pediatric intensive care and recent advances in mechanical ventilation during the last two decades have resulted in an exponential increase in the number of children undergoing home mechanical ventilation (HMV) treatment. Although its efficacy in chronic respiratory failure is well established, HMV in children is more complex than that in adults, and there are more considerations. This review outlines clinical considerations for HMV in children. The goal of HMV in children is not only to correct alveolar hypoventilation but also to maximize development as much as possible. The modes of ventilation and ventilator settings, including ventilation masks, tubing, circuits, humidification, and ventilator parameters, should be tailored to the patient's individual characteristics. To ensure effective HMV, education for the parent and caregiver is important. HMV continues to change the scope of treatment for chronic respiratory failure in children in that it decreases respiratory morbidity and prolongs life spans. Further studies on this topic with larger scale and systemic approach are required to ensure the better outcomes in this population.

Influence of ventilation rate on the aerodynamic interference between two extra-large indirect dry cooling towers by CFD

  • Ke, S.T.;Liang, J.;Zhao, L.;Ge, Y.J.
    • Wind and Structures
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    • v.20 no.3
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    • pp.449-468
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    • 2015
  • Current wind-resistance designs of large-scale indirect dry cooling towers (IDCTs) exclude an important factor: the influence of the ventilation rate for radiator shutter on wind loads on the outer surfaces of the tower shell. More seemingly overlooked aspects are the effects of various ventilation rates on the wind pressure distribution on the tower surfaces of two IDCTs, and the feature of the flow field around them. In order to investigate the effects of the radiator shutter ventilation rates on the aerodynamic interference between IDCTs, this paper established the numerical wind tunnel model based on the Computational Fluid Dynamic (CFD) technology, and analyzed the influences of various radiator shutter ventilation rates on the aerodynamic loads acting upon a single and two extra-large IDCTs during building, installation, and operation stages. Through the comparison with the results of physical wind tunnel test and different design codes, the results indicated that: the influence of the ventilation rate on the flow field and shape coefficients on the outer surface of a single IDCT is weak, and the curve of mean shape coefficients is close to the reference curve provided by the current design code. In a two-tower combination, the ventilation rate significantly affects the downwind surface of the front tower and the upwind surface of the back tower, and the larger positive pressure shifts down along the upwind surface of the back tower as the ventilation rate increases. The ventilation rate significantly influences the drag force coefficient of the back tower in a two-tower combination, the drag force coefficient increases with the ventilation rate and reaches the maximum in a building status of full ventilation, and the maximum drag coefficient is 11% greater than that with complete closure.

A Study on Fire ventilation design of road tunnel (도로터널에서의 화재환기 설계에 관한 연구)

  • Kim, Myung-Bae;Choi, Byung-Il;Choi, Jun-Seok;Han, Yong-Shik
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.6 no.2
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    • pp.129-139
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    • 2004
  • The several assumptions and design parameters to determine the ventilation rate in tunnel ventilation system were examined. In longitudinal ventilating tunnel, the ventilation rate has been determined by the critical velocity above which the smoke propagation to the upstream of ventilating air is prevented. Based upon the examination of assumptions and experimental results, we suggested the improved method to determine the critical velocity. In transverse ventilating tunnel, we found that the ventilation rate has been determined in accordance with the custom rather than fire-smoke dynamics such as the critical velocity in the longitudinal ventilating tunnel. It is because the ventilation rate in the transverse ventilation system has been determined by considering only the ventilation of contaminant by vehicle. To improve the ventilation design parameters based upon the fire-smoke dynamics, we conducted model tunnel fire experiments. From the experimental results, smoke propagating distance and smoke filling were suggested as the design parameter to determine the ventilation rate in transverse ventilating tunnel. And tunnels in Europe designed by the custom is found to have the dangerous nature in view of fire safety.

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A Study on Characteristic Analysis for Indoor Ventilation Performance of Mechanical Ventilation System (기계 환기시스템의 실내 환기성능 특성 해석에 관한 연구)

  • Ku, Jae-Hyun
    • Journal of the Korean Institute of Gas
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    • v.16 no.2
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    • pp.31-37
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    • 2012
  • This paper describes to analyze the ventilation performance of a room air conditioner for indoor comfort control. An experimental apparatus consists of a test room, the room air conditioner, a tracer gas measurement system, a supply fan and a controller. Ventilation performance as a function of human occupancy is evaluated with supply ventilation air using a tracer gas technique of CO2 gas in the test room. The ventilation performance is evaluated in a step-down method based on ASTM Standard E741-83 and is found to increase with increasing supply ventilation rate. The CO2 gas concentration is decayed rapidly without human occupancy. The ventilation performance without human occupancy increases up to 55% and the ventilation performance with one person increases up to 25% at the supply air of 570 lpm comparing with a natural reduction after one hour. A modeling for ventilation performance of a room air conditioner in a test room is presented using experimental datum.

Development of Road Tunnel Ventilation System with Electrostatic Precipitator (도로터널용 전기집진시스템 개발)

  • Kim, Jong-Ryul;Weon, Jong-Oung
    • Proceedings of the SAREK Conference
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    • 2008.11a
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    • pp.80-83
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    • 2008
  • As SOC (Social Overhead Capital) has been expanded, the highway road construction has been accelerated and city road system has been more complicated. So, long road tunnels have been increased and traffic flow rate also has been raised. Accordingly, the exhausting gas of vehicle cars seriously deteriorates the tunnel inside air quality and driving view. In order to improve tunnel inside air quality, we may need to introduce a compulsory ventilation system as well as natural ventilation mechanism. The natural ventilation mechanism is enough for short tunnels, meanwhile longer tunnels require a specific compulsory ventilation facility. Many foreign countries already have been devoting on development of effective tunnel ventilation system and especially, some European nations and Japan have already applied their developed tunnel ventilation system for longer road tunnels. More recently, as the quality of life improved, our concerns about safety of driving and better driving environment have been increased. In order to obtain clearer and longer driving view, we are more interested in EP tunnel ventilation system in order to remove floating contaminants and automobile exhaust gas. Evan though it's been a long time since many European countries and Japan applied more economical and environment-friendly tunnel ventilation system with their self-developed Electrostatic Precipitator, we are still dependant on imported system from foreign nations. Therefore, we need to develop our unique technical know-how for optimum design tools through validity investigation and continuous possibility examination, eventually in order to localize the tunnel ventilation system technology. In this project, we will manufacture test-run products to examine the performance of system in order to develop main parts of tunnel ventilation system such as electrostatic precipitator, high voltage power generator, water treatment system, etc.

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Analysis of Indoor Air & thermal environment with Hybrid Ventilation system during summer (하계 공동주택 하이브리드 환기시스템 적용에 따른 실내공기 및 열 환경 평가)

  • Kim, Sang-Jin;Kim, Eun-Soo;Kim, Tae-Yeon;Leigh, Seung-Bok
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.387-392
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    • 2006
  • The recent on indoor air problem has led to many studies on the methods and effects of ventilation for better indoor air quality. Although natural ventilation is the most effective and energy-saving method in residental housings, the small size of openable window has been a problem in high-rise residential buildings to ventilate only through natural ventilation. Consequently, the installation of mechanical ventilation system has been a requirement in residential buildings, and has caused other problems such as increase of energy consumption and SBS. Hybrid ventilation which uses forces of both natural and mechanical power has been introduced to solve the problem of increase in energy consumption with natural ventilation. In this paper, two types of hybrid ventilation systems in residential building were introduced. One type was with natural ventilation through vent grille in the window, and another type was with natural ventilation through ceiling duct while both types used mechanical ventilation system with the outlets. The indoor temperature distribution and pollution density distribution in summer while operating the ceiling air conditioner were analyzed through CFD simulation. In this paper, the optimal location of diffusers to achieve thermal comfort would be proposed.

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