• 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.

• Architectural research
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• v.1 no.1
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• pp.47-53
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• 1999

An interesting of desktop air-conditioning system is the Personal Environmental Module(PEM) System. The PEM system allows the occupant to choose the desired temperature, air volume and direction of the discharged air. In this study, the measurements on the age of air and the air change effectiveness, using the tracer gas method, are carried out to analyze the ventilation performance for provision of fresh air near the breathing zone by the PEM. The relations between the PEM for optimal control and other factors related to indoor air quality, and the ventilation for the PEM are examined. Also, three different supply diffuser types(desktop, floor and ceiling) are compared in view of their ability to distribute supply air to the workstation breathing zone. The desktop diffuser type could deliver air directly to the occupants breathing zone with a high degree of effectiveness. The minimum local age of air was measured in the breathing zone, which is directly supplied with air from the PEM diffusers, and the measured local air change effectiveness of the desktop diffuser in the breathing zone was about 1.13 to 1.23 times greater than that of the ceiling and floor diffusers. When the minimum outside air change rate as specified using ASHRAE Standard 62R is supplied with a desktop diffuser type, the volume of outside air can be reduced 13 to 23%, resulting in a commensurate in ventilation energy use.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.143-146
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• 2006

There has been growing concern regarding IAQ(Indoor Air Quality) recently, and IAQ problems from the air-tightness and use of chemical materials addition to the building materials have become increasingly important factors in the built environment. Ventilation is supposed as the solution of healthy indoor quality, and Korea government requests that all new apartment buildings must have a ventilation system as a matter of duty since January, 2006. The purpose of this study is to investigate the indoor concentration change of VOCs include the Formaldehyde according to many different ventilation supply types. Results showed that the reduction effect of target pollutants by the ventilation system was very slight. The cause of these results was attribute to increase the emission rate of building materials by increasing the ventilation rate.

• Journal of the Korea Safety Management & Science
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• v.19 no.4
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• pp.115-123
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• 2017

Recently there is a growing interest in the airborne spread of virus. In particular, there is growing interest in secondary infection through the air in the hospital. The distribution of air-born virus depends on ventilation system installed in a hospital. In this study, simulations were carried out to predict the move of air-born virus by ventilation system at hospital. Simulation results showed that pressure distribution was -372.05Pa ~ -3.45 Pa at 1st floor incase of only used mechanical exhaust at bathroom, shower stall, storage, kitchen etc.. if ventilation switch from used mechanical exhaust to mechanical exhaust & mechanical supply. Simulation results showed that pressure distribution was -336.44Pa at stair hall < -0.2Pa at bathroom < mean 1.19Pa at other room. So simulation results showed that using all of the mechanical supply and mechanical exhaust was more effective then the mechanical exhaust for maintain the pressure distribution in hospital. It was also showed that when using the mechanical supply and mechanical exhaust more effectively prevention of air born virus diffusion.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.405-410
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• 2006

This paper presents a control algorithm of supply and exhaust diffusers by recognizing a contaminant source location. CFD analysis has been conducted to calculate steady state airflow and concentration distributions in a model room, which has two supply and two exhaust openings on the ceiling. Calculations have been performed for five cases out of nine different ventilation modes by combining on/off control of the supply and exhaust openings. Local mean residual life times are obtained and compared at 9 internal points for each ventilation case. Depending on the contaminant source location, the ventilation system is operated at an optimum ventilation mode, which can results in maximum exhaust performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1523-1528
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• 2008

In this study, the ventilation system of connection passage and elevator hall of underground parking lot in apartment houses is investigated to extract the data for the installation and the application by the experimentation. In case of the elevator hall, actual air exchange rate is predicted fivefold higher than air exchange rate by infiltration and exfiltration. Ventilation system is installed good by supply air and return air. As the next best thing, it is installed by supply air because of IAQ control. The temperature of connection passage and elevator hall uniformly with $7{\sim}8^{\circ}C$, is maintained even if the operating condition of ventilation system is different. Therefore, the installation of the preheater, which is installed at the inlet of ventilation system for the cold draft in winter, is not essential in southern area of Korea.

• International Journal of Air-Conditioning and Refrigeration
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• v.10 no.4
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• pp.177-183
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• 2002

A pulsed tracer gas technique is applied to measure the distributions of local mean age and local mean residual-life-time of air in a half-scale experimental chamber, The airflow patterns in the chamber are visualized by a Helium bubble generator for three different exhaust locations. A supply slot is located at the top of a right wall, and an exhaust slot is at either bottom-left (Case 1), bottom-right (Case 2), or top-left (Case 3) location. Results show that the distributions of local mean age and local mean residual-life-time are different from each other, but both of them are closely related to the airflow pattern in the space. Included are discussions on explaining the variations of overall room ventilation effectiveness depending upon airflow rates for three different supply-exhaust configurations.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.39-44
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• 2005

Recently according to the fashion of well-being, it is increasing that heat recovery ventilator is applied to the apartment housing, But the uniform locations of inlet and outlet in each room may provide better indoor air quality than ununiform locations of inlet and outlet. Proper design of air supply system requires information concerning the gas concentration difference between the ventilation effectiveness at the breathing line. This paper presents models to predict the gas concentration difference and the ventilation effectiveness, based on the two cases with proper number of outlets. As one of the results it is desirable to set the outlet location near the furniture which produce the contamination gas so much.

• 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.

• Journal of the Korean housing association
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• v.15 no.3
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• pp.101-108
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• 2004

To find more efficient exhaust effect, air curtain of upward or downward trend in gas table and left or right side of range hood were made. As result that film vapor from range hood lower part by digital camera, the air current change by moving existence and nonexistence of exhaust fan and direction of air curtain were known. Under all experiment condition, upward air curtain superior exhaust performance.