• Title/Summary/Keyword: Ventilation system air flow rate

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A study on the ventilation characteristics and design of transverse ventilation system for road tunnel (도로터널 횡류환기방식의 환기특성 및 시스템 설계 관한 연구)

  • Ryu, Ji-Oh;Kim, Hyo-Gyu
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.20 no.2
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    • pp.305-315
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    • 2018
  • In this study, the ventilation characteristics and the relationships between the required ventilation flow rate and the ventilation system flow rate was investigated by numerical method for the optimum design of the transverse ventilation and semi-transverse ventilation system in road tunnels. The following results were obtained. In supply exhaust transverse ventilation system, the system supply-exhaust air flow rate is theoretically equal to the difference between the required ventilation flow rate and natural ventilation flow rate. However, it is shown that it increases by about 10% in the analysis results. And, in the case of the longitudinal air flow rate is increased by installed jet fans, ventilation system air flow rate is reduced. However, as the longitudinal air flow rate increases, the concentration of pollutants in the tunnel decreases, so the exhaust effect of pollutants decreases, and the effect of reducing the system air flow rate is decreased. In case of semi-transverse with only air supply, ventilation system air flow rate is equal to required ventilation air flow rate when tunnel inlet velocity is negative, but results is shown it is increased within about 13.3%. Also, it was found that ventilation effect can not be expected even if the jet fans are increased when the tunnel inlet velocity is negative.

Analysis of Air Flow Rate through Subway Vent Shaft with Mechanical Ventilation System for Shape Change of Vent Shaft

  • Kim, Jung-Yup
    • International Journal of Air-Conditioning and Refrigeration
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    • v.17 no.2
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    • pp.45-51
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    • 2009
  • Three-dimensional numerical analyses of mechanical ventilation system in vent shaft of subway in operation are carried out in relation with the different air flow passage of vent shaft and two ventilation operation modes of push/pull, The ventilation characteristics of vent shaft with regard to the shape change are evaluated. And the air flow rate through the vent shaft by ventilation system is measured within subway in operation to assess the accuracy and applicability of the numerical analysis method. The decrease of air flow rate due to vent-shaft change are between 0.7 to 2.2% in the cases examined.

The Comparative Experiment of Duct Design Method with Equal Friction Loss Method and T-Method on a House Ventilation System (등압법과 T-Method법을 이용한 주택환기시스템 덕트설계법의 비교실험)

  • Joo, Sung-Yong;Kim, Kwang-Hyun;Choi, Seok-Yong;Yee, Jurng-Jae
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.99-104
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    • 2006
  • Accurate flow rate distribution has been become a very important part for controling of air change rate since the introduction of house ventilation system. An inappropriate selection of fan due to Incorrect prediction of friction loss makes waste energy. The purpose of this study is to recognize applicability of T-Method at house ventilation system by comparing experiment with T-method, The result of this study is as follows Flow rate is small amount in a house, so duct size must be accurate. And duct design with Equal Friction Loss Method presented large error range. Equal friction loss method is not fit to applicate small amount air flow rate. T-Method predicts accurate flow rate comparatively in a house ventilation system. Error range was 3.5%.

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Performance of Local Exhaust Ventilation Systems of Degreasing and Plating Workplaces (일부 탈지세척 및 도금공정 국소배기장치의 성능점검과 개선방안)

  • Han, Don-Hee
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.8 no.2
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    • pp.178-185
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    • 1998
  • In order to evaluate and improve the performance of local exhaust ventilation systems for two TCE degreasing (A, B) and two electroplating (C, E) and one acid dipping & plating (D) operations located in Kimhae, the performance test was conducted with trace gases and a thermal anemometer (Kanomax 24-6111, Japan). For the inadequately designed systems, the improvement and redesigns in compliance with recommendation by ACGIH was suggested. The results of performance test for each system are as follows; 1. System of Workplace A was generally well-designed. Actual exhaust air flow rate was in excess of 68% above the recommended standard exhaust air flow rate. 2. System of Workplace B was very well-designed and completely enclosed. 3. All systems of Workplace C including hoods were poorly-designed and actual exhaust air flow rates were insufficient for open tanks. All systems should be upgraded according to ACGIH recommendations. 4. Supply and exhaust air flow rate of push-pull exhaust systems in Workplace D should be greatly increased. The width of flange of dipping tank hood should be increased with the value suggested. 5. System of Workplace E was well-designed. Actual exhaust air flow rate was in excess of 54% above the required.

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Air Flow Prediction and Experiment by T-Method According to Duct Layout on House Ventilation System (주택환기시스템의 덕트 Layout에 따른 T-Method의 풍량 예측 및 실험)

  • Joo, Sung-Yong;Yee, Jurng-Jae
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.523-528
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    • 2008
  • The accurate distribution of flow rate has been a very important part to control the air change rate since introduction of house ventilation system. An inappropriate selection of fan due to incorrect prediction of pressure loss in duct brings energy loss. In the previous study the pressure loss of general spiral duct was measured and database was constructed for finding correct loss factors in fitting upper stream. The purpose of this study is to compare and investigate the error range of flow rate by applying T-Method to bilateral symmetry and asymmetry layout of duct. The results of this study are as following. It is demanded to decide accurate size under duct design for house ventilation system. Because the small amount of Flow rate was considered at that time. The error range was 3.17% on case1 and 3.52% on case2. The error range difference was 0.35%.

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Performance Evaluation of Multidrop Chamber Ventilation System in Apartment (공동주택 적용을 위한 다분기챔버 환기 시스템의 성능평가에 관한 연구)

  • Kim, Sung Soo;Sohn, Jang yeul
    • KIEAE Journal
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    • v.9 no.4
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    • pp.17-22
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    • 2009
  • It is common to design the duct branches where to supply the required air flow for individual room in residential apartment house. However it is difficult to adjust the air volume adequately in small air duct branches in residential ventilation system. The purpose of this study is to figure out the performance of Multidrop chamber coupling system for the residential ventilation system. The experiments were designed to simulate apartment of $84m^2$ and established multidrop chamber duct and general duct on the ceiling of the apartment. Distribution performance of air supply rate were evaluated in this experiments. As a result, distribution performance of air supply rate in the general duct is different from designed air supply rate by about 35% ~ 50% and about 10% in the multidrop chamber system. In additional the sound insulation performance of the multidrop chamber system decreased about 20% compared with general duct system. Therefore, the multidrop chamber system is considered to satisfy proper air supply rate of each room and to improve the sound insulation performance in apartment Houses.

Analysis of Air Flow Rate Distribution for the Bathroom Exhaust System in High-rise Buildings Using T-method (T-method를 이용한 고층 아파트 욕실 배기 시스템의 층별 유량분배 해석)

  • 문종선;강석윤;이승철;유호선;이재헌
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.3
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    • pp.265-272
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    • 2004
  • Based on the T-method, a new scheme for predicting air flow rate distribution in a bathroom exhaust system is developed. Introduction of individual duct route enables us to disintegrate a complicated multi-fan ductwork into a set of simultaneous single-fan subsystems. The scheme is validated via the analysis of a well-posed test problem, showing physical consistency. In order to demonstrate the utility and capability of our method, the bathroom ventilation system in a 20-story residential building is selected as an example. Under the typical design condition, the air flow rate of each exhaust fan at the balancing point is successfully predicted, and such information can lead to an engineering estimation for the overall system performance. While some deficiencies in ventilation are found at bathrooms at lower floors with 6mmAq-rated exhaust fans, they disappear over the whole building by using fans of enhanced static pressures, 7 and 8mmAq. Finally the present scheme seems to be useful for practical design of multi-branched, multi-fan ventilation systems.

Analysis on Ventilation Performance of Natural Ventilation Systems in Multi-Family Housing Using Blower Door Test (Blower Door Test를 이용한 공동주택 자연환기시스템의 환기성능 분석)

  • Kim, Min Seok;Auh, Jin Sun;Hong, Goopyo;Kim, Byungseon Sean
    • KIEAE Journal
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    • v.16 no.6
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    • pp.129-134
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    • 2016
  • Today, natural ventilation systems are widely applied in multi-family housing. However, studies using the wind data trend line of the blower door test are insufficient. Purpose: Through this study, we will propose a computational method about ventilation performance of natural ventilation systems by conducting blower door test. Method: First, we sealed the gaps between the main systems including the natural ventilation system and conducted the blower door test. Next, the natural ventilation system was opened, the blower door test was conducted, and the difference in air flow rate between when closed and when opened was checked. Blower door test was carried out with a pressure difference of 50 Pa. Result: Therefore, the ventilation performance of the natural ventilation system was checked by drawing a trend line using the data to calculate the air flow rate at 2 Pa of the natural ventilation equipment standard pressure difference.

A Study on Application of Distributor for Duct Design at House Ventilation System (주택용 환기시스템의 덕트설계를 위한 분배기 적용성 검토)

  • Yee, Jurng-Jae;Choi, Seok-Yong;Kim, Seok-Keun;Kim, Kwang-Hyun;Lee, Young-Woo;Kim, Hwan-Yong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.11
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    • pp.770-775
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    • 2007
  • Although these days application of heat recovery ventilation and improved kitchen ventilation system came into wide use in mixed-use residential buildings and exclusive residences, there are not enough ventilation systems except the local ventilation of kitchens and rest rooms. It is very important part to regulate and distribute correct air flow rate for controlling air change rate. The purpose of this study is to investigate the application of distributor at house ventilation system by comparing a duct system with out distributor and with distributor. The results of this study are as follows. (1) When using distributor though the size of duct diameter is reduced rapidly, the pressure loss doesn't rise largely. The pressure loss without distributor is 4.08 mmAq, the pressure loss with distributor 4.10 mmAq. (2) To use distributor can reduce materials of duct and secure enough ceiling space by reducing duct diameter. (3) Diameters and air flow paths of distributor on the design stage are important part for accurate air flow rate.

Numerical Analysis of Ventilation System for Dust Removal Inside the Enclosed Conveyor Belt (밀폐된 컨베이어 벨트 내부의 분진 제거를 위한 환기 시스템의 수치해석적 분석)

  • Yeseung Lee;Ki Jin Jeong;Jong Min Kim;Jung-Hun Noh
    • Particle and aerosol research
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    • v.19 no.2
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    • pp.43-53
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    • 2023
  • In this study, the ventilation system of the enclosed conveyor belt for coal transportation was evaluated, and the particle removal efficiency according to the ventilation conditions was identified using computational fluid dynamics and particle behavior analysis. The most effective way to remove dust generated inside the closed conveyor belt is to adjust the position of the exhaust port of the duct so that the air is exhausted around the rear of the conveyor belt. And this method seems to work for another narrow and long spaces where air enters in one direction. In addition, when the air flow rate of the each duct was less than 300 CMM, it was efficient to increase the flow rate of the duct located at the rear of the conveyor belt, and when the flow rate of the each duct was higher than 300 CMM, it was efficient to increase the flow rate of the duct located at the front of the conveyor belt.