Balancing adjustment of exhaust duct system using feedback simulation method

Chen, Huei-Jiunn; Wang, David W.P.; Chen, Sih‐Li

doi:10.1016/j.applthermaleng.2005.08.001

Cited by 19 publications

(1 citation statement)

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“…The outcomes largely depend on engineers' experience. To overcome this problem, simplified way by using the ratio of the junction pressure (SPJ') to the hood static pressure (SPH') for each branch was proposed to avoid repeated velocity determinations that required before [16].Some new methods based on both theoretical calculation model and measuring feedback data have been also studied and made some improvements [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

A novel flow-guide device for uniform exhaust in a central air exhaust ventilation system

Tong

Gao

Luo

et al. 2019

Building and Environment

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Exhaust ventilation system with one central fan and multiple terminals has been widely used for the heat and contaminant removal in building environment. Conventional design without pressure balancing leads to uneven distribution of exhaust airflow rate among the multiple outlets. Existed balancing methods usually uses dampers (constant-air-volume valve or regulating valve), tapered duct, or varied inlet area. However, these methods result in higher fan energy consumption, or complicated construction and on-site commissioning. In this paper, a flow-guide device was developed for adjusting the pressure distribution of duct branches. This new device is integrated with the interflow Tee-junction and does not need any commissioning or regulating. The resistance performance of the device responding to the structural parameter was derived using the CFD simulation and experiment. The negative direct resistance featured by the device was found to effectively benefit exhaust at the outlets farther away from the central fan. The ductwork hydraulic model based on the Bernoulli's law of airflow and the fitted resistance correlations were further proposed to fulfill the parametric design. Finally, full-scale test was carried out for a central exhaust system installed with the flow-guide devices referring to a factory workshop with 30 heat and contaminant sources. Compared to the system without the devices, the total rate of the system increased by 25%. Discrepancy of exhaust rate decreased by 78% and uneven degree decreased by 82%, which well meets the engineering balancing requirement. Meanwhile, total resistance of the system reduced 23.8% owing to the negative loss the devices bring.

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