• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.20 no.4
• /
• pp.238-244
• /
• 2008

This study investigates on the improvement of inhalation effect of hood which attached new device named as "gas-guide-device" in local exhaust ventilation system for the effective elimination of harmful material and dust in manufacturing factory. The gas-guide-device having a diamond shape is composed of width (b) and two sides of a device (X, Y) and its size is selected the industrial hood under application in manufacturing factory after due consideration. In order to investigate the effect of gas-guide-device, numerical and experimental study is performed that the flow velocity is calculated and is measured by a commercial program "COMSOL $Multiphysics^{TM}$" and a hot wire type of anemometer, respectively. The numerical and experimental results are revealed is a similar pattern and flow velocity has improved to hood attached gas-guide-device. Also, the numerical method and result is also verified the dependance. Moreover, the optimum shape and size of gas-guide-device is revealed that the width (b) and the ratio of two sides of gas-guide-device (X, Y) has 125mm and 4 to 6.

• International Journal of High-Rise Buildings
• /
• v.2 no.2
• /
• pp.115-121
• /
• 2013

The ventilation performance of a street in Bangkok, Thailand, was investigated by performing measurements and conducting a CFD analysis. We focused on a street that was covered by an elevated train station. It was shown that the ventilation efficiency varied drastically depending on the angle between the street and the wind direction. When the wind direction was parallel to the street, the elevated structure had a negative influence, which created higher pollutant concentrations than in locations without elevated structures. However, when the wind direction was perpendicular to the street, the pollutant concentrations in the two situations were similar. Using a CFD analysis and ventilation performance indexes, it was shown that the elevated structure directed the wind flow and enhanced the ventilation efficiency, which positively affected ventilation performance. These kinds of knowledge can lead us to optimize city planning including high-rise buildings with high ventilation efficiency.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.29 no.3
• /
• pp.343-350
• /
• 2019

Objectives: This study aims to identify whether ventilation conditions and their effectiveness can be significantly improved in an experimental chamber by increasing the mixing factor (K-Factor). Methods: In a chamber with a volume of $1m^3$, air velocity was measured at six different points with four roof fans in the upper part of the chamber being operated in order. The impact of the ventilation conditions was analyzed when the flow rates were increasing and the first inlet of the chamber was either open or closed. Smoke patterns were also observed at four corner points where ventilation was limited. Kruskal Wallis and Mann-Whitney tests were performed to compare air velocities measured in the chamber. Results: The air velocities measured at only the third point increased significantly from $0.03{\pm}0.03m/s$ (door open) and $0.05{\pm}0.06m/s$ (door closed) with two fans, $0.08{\pm}0.08m/s$ with three fans, and $0.09{\pm}0.09m/s$ with four fans operating (p<0.05). However, air velocities at the four corner points did not significantly increase. Smoke patters also showed that the open inlet of the chamber had no effect on improvement of ventilation conditions and effectiveness. Conclusions: In this study, the air velocities at six points in the chamber did not significantly increase despite the increase in the mixing factor and flow rates of ventilation in the controlled environment. Therefore, the inflow of outdoor air throughout an open inlet and installation of a forced ventilation system can potentially increase the indoor air velocity and improve ventilation condition without an increase in the mixing factor.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.34 no.1
• /
• pp.35-47
• /
• 2024

Objectives: Many cases of lung cancer have been reported by school kitchen workers as occupational cancer. Twenty-eight schools in Gyeongsangnam-do Province were selected to evaluate the effect of improved kitchen ventilation systems. Ventilation characteristics before and after renovation were compared and design techniques were identified. Methods: In the design stage for kitchen ventilation systems, expert intervention was used to improve the designs. Ventilation characteristics and air quality were evaluated before and after the renovations. Hood face velocity and fan flow rate were measured and the smoke visualization technique was used to evaluate the capability of protecting worker's breathing zone. The concentrations of PM_0.3 were measured at points not adjacent to cooking equipment because these concentrations fluctuate greatly. Results: Mean hood face velocity increased from 0.29 m/s before renovation to 0.7m/s after renovation. The concentrations of PM_0.3 showed a roughly 95% reduction. Concentrations of CO showed more than a 75% reduction. Smoke visualization showed greater protection of workers' breathing zone. Conclusions: Advanced design techniques for school kitchen ventilation systems were applied to renovate old kitchen ventilation systems. The performance of the new kitchen ventilation systems was nearly excellent. Further improvement of design techniques is still needed, however.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.3
• /
• pp.463-469
• /
• 2009

We performed the experimental study on the control of suspended dust in a cement packaging process for various ventilation systems. To effectively remove the dust generated in the cement packaging process, three different kinds of ventilation system, such as local exhaust ventilation, electrostatic scrubber, and local air supply system, were adopted. Dust concentrations in the packaging process were measured with the variation of the airflow rate of the ventilation systems and then their ventilation performance were evaluated. From the results, we knew that the ventilation performance was the best when the local exhaust ventilation and the electrostatic scrubber were simultaneously operated in the packaging process. In the electrostatic scrubber system, the effect of the airflow rate on the indoor dust removal efficiency was negligible so hat he system ust be operated at $2,700m^3/h$ for saving power consumption.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1993.10b
• /
• pp.213-218
• /
• 1993

The paper deals with problems connected with heating and ventilation of underground premises for public use. Some properties of rock and special problems connected with designing ventilation systems for underground spaces are first briefly discussed. The rest of the paper deals with design of ventilation and heating systems. The conclusion is that there are no large problems with heating and ventiliation of underground premises, but there are still problems connected with for instance thermal properties of rock when water flows in the cracks. An optimum design demands better knowledge of these properties.

• 유체기계공업학회:학술대회논문집
• /
• 2005.12a
• /
• pp.367-372
• /
• 2005

This study primarily is concerned with a new device which has been developed following the international standards to measure the ventilation performance at elevated temperature. This device can measure duration of ventilation, performance of electricity, static pressure at elevated temperature and also it is having provision to measure reversible performances during fire hazards. Invented device is closed circuit type system which is best suited for korean industrial environment with low cost and high efficiency. International standards has been compared and performance testing has been major using BS 7346 which is tested by Warrington Fire Research Centre.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.31 no.1
• /
• pp.60-72
• /
• 2021

Objectives: This study was performed to investigate the level of participation in and satisfaction with training courses at job training institutions and to improve participation and satisfaction through changes in the training method for industrial ventilation subjects. Methods: The results were analyzed for the mean and standard deviation by t-test and ANOVA, (p=0.05). Participation rates were examined for three courses: specialization, job training, and supervisory. The participation inthe education was 428 people, and the result of satisfaction with the change of education method was 878 people. Satisfaction was investigated for the specialized curriculum and job training curriculum,but not the supervisor curriculum. The satisfaction results for six items(contents, quality, skill, level, degree of understanding, degree of practical) were analyzed according to the change in the training medium and the method among people in one occupational ventilation subject. Results: The participation rate was similar in the job training and specialized training courses, but the lowest rate was in supervisory courses(p=0.05). In general, there was the lowest participation on the first day of education, and the participation rate improved after the second day. Satisfaction with the course was high for the specialized education course with a number of practical education assignments(p=0.278). The satisfaction level for the teaching method in the industrial ventilation subjects was high in a mixed group which combined lecture and practice. The industrial ventilation course in the basic job training course showed a difference between lecture and mixed education(p=0.111), but there was no significant difference. However, the industrial ventilation course in the advance job training course showed a clear difference between lecture and the mixed education(p=0.036). Conclusions: Therefore, the first day of training should start in the afternoon so that more trainees can participate, and it is recommended to assign important subjects after two days. In addition, it is suggested that job competency-enhancing education utilize various educational methods and media.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.7
• /
• pp.4047-4051
• /
• 2014

Modern apartment houses are constructed to be relatively airtight with a high heat insulation system to increase the energy efficiency. Such a system has a range of deleterious effects due to the insufficient ventilation. In this study, the ondol system, which is used as a heat source typical of winter in Korea, was set as the default system to evaluate the indoor heat environment according to the ventilation method, the factors of energy reduction by the ventilation system was analyzed. The experimental apparatus was used to simulate the ambient conditions for a certain constant temperature and humidity chamber. The experimental results showed that the supply water temperature higher air volume decreases with increasing supply air temperature in the following order: floor supply/exhaust > total heat exchange supply/exhaust > forced supply/exhaust. Through this study, the applicability of various ventilations could be examined.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.33 no.3
• /
• pp.280-283
• /
• 2023

Objectives: The purpose of this study was to examine the change in exposure concentration in the cleaning process after installing a local exhaust system. Methods: Dichloromethane measurement was conducted according to the KOSHA Guide (A-19-2019). Results: After the local exhaust device was installed, a total of three measurements were conducted, including temporary work environment measurements, and all of the measurements did not exceed the DCM exposure standard, but were more than 50% of the DCM Time Weighted Average((8-TWA) Conclusions: It is thought that the local ventilation system of a small business needs not only support for the initial installation cost, but also educational support for maintaining the performance of the local ventilation system and support for consumables (adsorbents, filters, etc.) that incur periodic costs.