• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.2
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• pp.202-211
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• 2007

Ventilation system is being recommended as an effective tool to improve indoor air quality (IAQ) in apartment houses. Recently, in Korea, apartment house suppliers must establish ventilation system in apartment houses in law. In this study, improvement of IAQ by establishing mechanical ventilation system at apartment house was investigated by mockup test. Seven apartment houses were arranged for the test and improvement of IAQ was examined under the various conditions of ventilation rates, ventilator type and duct works. The results of this study show that IAQ in the test houses which were established mechanical ventilation system was improved about from 30% to 40% compared with IAQ in the apartment house which was not established ventilation system. However, there were no apparent concentration differences between the cases of changing ventilation rates, ventilator types and ductworks.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.88-96
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• 2008

Effects of the duct inlet guide vane on the flowrate distribution characteristics of the defroster nozzle exit in a defrost duct system were investigated experimentally to design the optimum heating, ventilation and air conditioning (HVAC) system applied in an automotive compartment. A 3-dimensional hot-wire anemometer system was used to measure the velocity field in the vicinity of the defroster nozzle jet flow and the velocity distributions near the windshield interior surface. At first, two cases of with- and without-duct inlet guide vanes were considered as the test condition, and then three cases of the duct inlet guide vane were tested to determine the optimum guide vane shape and their positions. The arrangement of the duct inlet guide vanes has an effect on the improved flowrate distribution at the defroster nozzle exit and near the windshield interior surface. However, the application of the lots of guide vane to control the flow direction leads to increase the flow resistance, resulting in the decreased flowrate issuing from the defroster nozzle. The shape of the duct inlet guide vane affects not only the flowrate distribution between the driver side and the assistant driver side but also the reduction of the flow resistance in the defrost duct system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.8
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• pp.739-745
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• 2001

The objective of this research is to analyze the ventilation effectiveness in the non-isothermal air supply using mixing and displacement ventilation systems for indoor air quality control and management. In this study, a ventilation effectiveness is evaluated in a simplified model chamber using a tracer gas technique of $CO^2$ gas injected into a supply duct as a function of ventilation rates, supply/extract sites and cooling/heating air supply. The ventilation effectiveness decreased with increasing ventilation rate on the cooling and heating conditions. And the ventilation effectiveness of case 3 (down supply and upper extract) was better thant that of case 1(upper supply and upper extract) and case 2(upper supply and down extract) with the cooling supply conditions. but for the heating supply air conditions, the ventilation effectiveness of case 2 was better than that of case 3 and case 1.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.610-618
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• 1998

In this study, a tracer gas technique was used to measure ventilation effectiveness in a thermal environmental chamber simulating an under-floor air conditioning system. A tracer gas of $SF_6$ was injected in a supply duct using step-up and step-down methods. Local mean ages and room mean ages were calculated from the measured concentrations under isothermal and cooling conditions with and without diffusers. Ventilation effectiveness is found to be higher in cooling ventilation operations than in isothermal operations. Results also show that ventilation effectiveness is not significantly affected by a diffuser.

• Journal of the Korean Society of Visualization
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• v.7 no.1
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• pp.3-8
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• 2009

Most vehicles have a heating, ventilating and air conditioning (HVAC) device to control the thermal condition and to make comfortable environment in the passenger compartment. The improvement of ventilation flow inside the passenger compartment is crucial for providing comfortable environment. For this, better understanding on the variation of flow characteristics of ventilation air inside the passenger compartment with respect to various ventilation modes is strongly required. Most previous studies on the ventilation flow in a car cabin were carried out using computational fluid dynamics (CFD) analysis or scale-down water-model experiments. In this study, whole ventilation flow discharged from the air vent of a real passenger car was measured using a special PIV (particle image velocimetry) system for large-size FOV (field of view). Under real recirculation ventilation condition, the spatial distributions of stream-wise turbulence intensity and mean velocity were measured in the vortical panel-duct center plane under the panel ventilation mode. These experimental data would be useful for understanding the detailed flow structure of real ventilation flow and validating numerical predictions.

• Journal of the Korean Society of Safety
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• v.25 no.1
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• pp.32-37
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• 2010

When back-out & firing Process applies heat, hume is piled up in exhaust duct by organic compound and it have high dangerousness. There by, the process is happening a lot of damage that is exhaust duct fire. However we do not have certain fire dangerousness estimation and digestion countermeasure. So we need preventive measure. Back-out & firing is a process which has fine structure, electrical and mechanical characteristics, such as firing kiln and back-out kiln which has pipe line and box type. The box oven is made of heating coil, fan motor and control panel. Back-out & firing process has air circulation institution of quick ventilation type. When we operate this process for long time, fire can break out easily. Duct is made by zinc shredder. If fire breaks out in duct inside, fire by deposit fume can be dispersed easily. Accordinglym, This project estimate danger for back-out & firing process exhaust duct through real fire test. And there is purpose of study to establish preventive measure.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.10 no.2
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• pp.78-97
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• 2000

Designing the industrial ventilation system is the complex and time-consuming job. It could generate some errors in the design calculations if one uses the hand-calculator or the spreadsheet program. To overcome these difficulties, VSDS(Ventilation System Design Software) had been developed a few years ago. But, it had the difficulty in designing a complex system having many branches because the user can not see the layout of the system on the screen. Another difficulty is that VSDS had been based on the assumption of the standard air condition. VSDS has thus been improved to overcome the shortcomings of the old version of VSDS.

• Journal of Environmental Health Sciences
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• v.31 no.5 s.86
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• pp.372-378
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• 2005

To enhance educational effect for exhaust ventilation system, more instructive educational engineering such as experimental system should be needed. This study was performed to 1) manufacture the basic experimental system for local exhaust ventilation, 2) experiment with this system and 3) develop methodology of exhaust ventilation education. With this system, three pressures (static pressure(SP), velocity pressure(VP) and total pressure(TP)) were measured and illustrated and the graphic shapes agreed to theoretical ones relatively. Entry loss factor ($F_h$) of each hood was found to be different with hood shape, duct velocity and flow rate. This result implies that precise $F_h$ should be determined case by case and a industrial hygienist should not be dependent on the existing values. Pressure loss using velocity pressure method and characteristics of air movement near hoods using fume were grasped with this system. But larger system should be recommended to produce more precise experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.17-23
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• 2017

This study is about the development and revision of a blower design for a ventilation system. In this study, to describe the flow in the 4000CMM grade blower, 3-dimensional steady-state turbulence was assumed to govern the flow equation. The flow field with velocity distribution according to the elbow duct of the ventilation system is also compared. Finally, vibration was observed in the blower at the installation to ventilation system. The cause was due to a problem in the manufacturing process of the airfoil type impeller.

• 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.