• Title/Summary/Keyword: HVAC duct

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Numerical Study to Improve the Flow Uniformity of Blow-Down HVAC Duct System for a Train (전동차용 Blow-Down HVAC 덕트 시스템의 유동 균일도 향상을 위한 수치적 연구)

  • Kim, Joon-Hyung;Rho, Joo-Hyun
    • The KSFM Journal of Fluid Machinery
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    • v.19 no.1
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    • pp.18-23
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    • 2016
  • A HVAC(Heating Ventilation and Air Conditioning) is adapted to increase the comfort of the cabin environment for train. The train HVAC duct system has very long duct and many outlets due to the shape of a train set. the duct cross section shape is limited by a roof structure and equipments. Therefore, the pressure distribution and flow uniformity is an important performance indicator for the duct system. In this study, the existing blow down type HVAC duct system for a train was supplemented to improve the flow uniformity by applying a design method combining design of experiment (DOE) with numerical analysis. The design variables and the test sets were selected and the performance for each test set was evaluated using CFD(Computational Fluid Dynamics). The influence of each design variable on the system performance was analysed based on the results of the performance evaluation on the test sets. Furthermore, the optimized model, whose the flow uniformity was improved was produced using the direct optimization(gradient-based method). Finally, the performance of the optimized model was evaluated using numerical analysis, and it was confirmed that its flow uniformity has indeed improved.

A Survey for the Air Treatment System according to the Position of HVAC and the Feature of Air Duct Structure in the Train (철도 차량의 HVAC 위치에 따른 공기조화 시스템 및 Air Duct 구조의 특성에 관한 고찰)

  • Jung, Hwa-Sic;Park, Jae-Hong;Yeom, Gyu-Hak
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.1330-1335
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    • 2007
  • The HVAC and the air duct is to make optimal indoor environment. By the HVAC position, method and the air duct construction, the important elements can affect on cooling performance, passengers' convenience, and energy efficiency. According to this, there are features, such as the indoor temperature distribution, cooling performance, velocity distribution from diffuser, tend to be come out variously. Also, comparing and analysing temperature distribution, cooling performance, air velocity, noise based on the real practical vehicle tests, it shows features in detail. Besides, it can lead to make design the system of HVAC & air duct effectively.

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Development of Cabin Noise Prediction Program Induced by HVAC System (공조시스템 유기 격실 소음 예측 프로그램 개발)

  • Kim, Byung-Hee;Kwon, Jong-Hyun;Cho, Dae-Seung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.554-558
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    • 2004
  • In this paper, we introduce noise prediction program of HVAC system to assist low-noisy design of ship's cabin. The developed program calculates sound power levels at HVAC components considering primary and secondary noise generated by fan and duct element, duct element noise attenuation, and duct break-in noise based on the authentic empirical method suggested by NEBB and acoustic power balancing method. Sound pressure level at cabin with or without ceiling system is evaluated by the diffuse-field theory considering diffuser and duct break-out sound powers. Moreover, the program provides intuitive pre- and post-processors using modem GUI functions to help efficient modeling and evaluation of cabin and HVAC component noise. To validate the accuracy and convenience of the program, noise prediction for a HVAC system is demonstrated.

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Evaluation of the Thermal and Noise Environment in an Ancient Tomb installed a Duct-type HVAC System (공조기가 설치된 고분 내에서의 열 및 음 환경 평가)

  • Park, Jin-Yang;Jun, Hee-Ho;Jun, Yong-Du;Lee, Kum-Bae
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.3
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    • pp.228-234
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    • 2007
  • Opening an ancient tomb interior can deal fair damage for preservation in long period because of high moisture. In this study, a duct-type HVAC system was installed to preserve an ancient tomb and temperature and humidity was measured to analyze heat environment. Armhole was measured to search whether an ancient tomb receives effects of vibration caused by a duct-type HVAC system. According to the measured data, temperature in an ancient tomb is kept adaptively in conservation regardless of a duct-type HVAC system installation when it rains in summer. The other side, humidity is kept adaptively in conservation when installed duct-type HVAC system. But when it is in natural state, a lot of humidity by dew condensation phenomena. So it needs a duct-type system for an ancient tomb conservation. In the case of vibration, measurement value of 3 satisfy control but Germanic DIN 4150 does not satisfy. Therefore, equip must be such that it can prevent vibration for safety.

A Case Study on the Analysis of Characteristics of Marine HVAC Duct - For the Development of Maintenance Robot's Movement Algorithm - (선박 공조닥트의 특성분석에 관한 사례 연구 - 유지관리용 로봇의 이동 알고리즘 개발을 위한 분석 -)

  • Hwang, Kwang-Il
    • Journal of Advanced Marine Engineering and Technology
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    • v.30 no.2
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    • pp.211-217
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    • 2006
  • This study is focused on the analysis of the characteristics of marine HVAC duct. These results will be applied to develope a robot which is for maintaining a cabin comfort, convenience and healthy through HVAC duct. The followings are the results of this study. (1) The evaluated items which proposed by at the view point of robot's function can be adapted to other vessels for the same purpose, (2) For the case of round type duct. the maximized conditions which robot has to have are straight length of 40.152mm, inclination of $45^{\circ}$. horizontal bending of $90^{\circ}$. increasing diameter of 1.28 times, and 0.625 times decreasing diameter in branch. (3) For the case of rectangular type duct. the maximized conditions are straight length of 15.987mm. aspect ratio of 4.17:1, inclination of $18.92^{\circ}$. horizontal bending of $90^{\circ}$, and 0.65 times decreasing diameter in branch.

A Study on the Duct Design of HVAC System Using the Equal Friction Method and the T-method (등압법과 T-method를 이용한 공조시스템 배관 설계에 관한 연구)

  • Park, Joon-Suk;Choi, Gil-Hwan;Cho, Dae-Seung
    • Journal of the Society of Naval Architects of Korea
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    • v.46 no.4
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    • pp.435-443
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    • 2009
  • Optimal duct design of a HVAC system requires analysis technology to accurately evaluate its pressure losses, flow rate and velocity for making a compromised design among fan capacity and duct size affecting initial manufacturing and operation costs, and noise induced by the HVAC system. In this paper, we carry out initial duct design using the equal friction method. Using the result, the T-method is applied for accurate analysis of flow rate. Then, the duct size is modified using the difference between the required and the calculated flow rate, which can guarantee required flow rate, reduce the pressure unbalance among duct paths and lead to select optimal fan performance. To verify the validity and effectiveness of the proposed design method, an example for HVAC system design including noise analysis is demonstrated.

Design and Economics of HVAC System for Reduction of Power Consumption in Blow Mold Machine (플라스틱 연료탱크 생산 설비에서의 소비 전력 저감을 위한 공조 시스템 설계 및 경제성 평가)

  • Lee, Youngjae;Choi, Seukcheun
    • Journal of Power System Engineering
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    • v.21 no.4
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    • pp.84-93
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    • 2017
  • This study was carried out to improve the electric power consumption of HVAC in the blow mold machine(BMM) and work environment. The experiment was conducted with the simulated HVAC system of 1/15 of the actual BMM. The temperature of main facility and two preheaters was fixed at 200 and $60^{\circ}C$ respectively in all test conditions. The measured points of temperature were chosen as critical locations considering the work environment. The tendency of temperature distributions decreases as the duct was closed to the main facility. The reduction rate of power consumption of HVAC increases up to 32.3% when both duct and cooling systems are operated. Also the efficiency of HVAC is improved about 9% through the modified design of duct system. It notes that the electric power consumption of HVAC can be reduced by the optimum design and operating condition of duct and cooling system.

Numerical Analysis of Three Dimensional Turbulent Flow in a HVAC Duct (HVAC 덕트내의 3차원 난류유동에 관한 수치해석적 연구)

  • 정수진;류수열;김태훈
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.4
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    • pp.118-129
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    • 1996
  • In this study, three dimensional flow analysis in a HVAC duct was performed computationally using various turbulence models and compared numerical predictions such as outlet flow split, surface pressure distribution along the duct to experimental data. It's well known that accuracy of computational predictions of flow heavily dependent on turbulent models and discritization method. Therefore, in this work, to assess the ability of turbulent models to predict characteristics of duct flow, three kinds of models, namely standard $k-\varepsilon$, RNG $k-\varepsilon$ and modified $k-\varepsilon$, containing parameter for the effect of streamline curvature were employed and validated one another by comparing with experimental data. In results, modified $k-\varepsilon$ turbulence model allows a successful prediction of static pressure distribution particulary at around strong curvature but little improvement flow split. In the futrue, adoption of CFD to design HVAC duct with modified $k-\varepsilon$ model will bring benefits of producing more accurate prediction, and also give designers more detail information much more than now.

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Characteristics of noise in HVAC duct for vehicle (차량용 공조덕트의 소음특성에 관한 연구)

  • Kim, Jae-Won;Kim, Jin-Min;Park, Jeong-Young
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.529-534
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    • 2003
  • Comprehensive study on the system, including blower and ducts, of HVAC device of a vehicle has been carried out for improvements of noise characteristics. The parameters of design improvements are concerned with geometric informations such as the shape of ducts and presence of a windshield window. Test results show that noise level increasing the following order: HV (HD) < V (D) < BH ${\sim}$ BHV (BHD) < B (B, H, V, D denote for blower, heater unit, vent duct, defrost duct, respectively). The effects of windshield glass on the noise level in the case of defrost mode are pronounced and the effects of the geometry of ducts on the overall HVAC noise prove to be not small.

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Aerodynamic Analysis of Automotive HVAC Duct for Enhancement of Cooling/Heating Performance (자동차 냉/난방 성능 향상을 위한 공기조화 덕트의 기류해석)

  • Ju, Jae-Woo;Lee, Ki-Don;Heo, Man-Woong;Kim, Kwang-Yong;Park, June-Kyu;Yun, Jung-Hwan;Kim, Hong-Bin
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.1
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    • pp.23-28
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    • 2012
  • In the present work, numerical analyses of air flow in HVAC duct have been carried out for enhancement of cooling/heating performance. For the analyses, three-dimensional Reynolds-averaged Navier-Stokes equations have been solved with the shear stress transport turbulence model. The numerical results were validated in comparison with the experimental data. Based on the numerical results, the HVAC duct was designed to reduce the pressure loss. The modified duct geometry shows largely reduced pressure drop in comparison with the reference geometry. And, through modified duct shape, the performance of air conditioning has been enhanced.