• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.7
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• pp.337-343
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• 2015

This paper investigates the ventilation characteristics in a two-dimensional underground network junction composed of four main lines interconnected by eight ramps. Simple one-dimensional models cannot be applied to network junctions since there are interferences of traffic piston effects in the main lines and at the ramps. A numerical algorithm was developed to analyze the pressure and airflow distributions iteratively. The Darcy-Weisbach equation was used to calculate the piston effects by traffic flows, and a Hardy Cross iteration was conducted for network analysis at the interconnected junction. The results show interesting ventilation characteristics and CO concentration distributions depending on system parameters such as vehicle speed, tunnel diameter, and other junction configurations.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.11
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• pp.1079-1087
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• 2005

In this paper, thermal comfort and ventilation performance characteristics in the lecture room with the ventilation system and two different air-conditioning systems, system air-conditioner or fan coil unit, were evaluated by experimental and numerical methods. We compared the measured data with the computational results of the predicted mean vote and carbon dioxide concentration. Additionally the ventilation effectiveness was calculated numerically. From a viewpoint of the uniformity of PMVs in the lecture room, the thermal distribution performance of the system air-conditioner was more effective than the fan coil unit. Carbon dioxide concentration and ventilation effectiveness were barely affected by the type of the air-conditioning system.

• Journal of the Korean housing association
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• v.12 no.3
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• pp.141-148
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• 2001

To design mechanical ventilation for bathroom of apartment houses where air supply and exhaust are taken into consideration, mock-ups of ventilation systems, widely used in bathroom of apartment houses with an area of 100$\textrm{m}^2$, were made and installed in a laboratory. These ventilation mock-ups were available for control of air supply and exhaust, and the sizes of supply openings were 40cm${\times}$1cm, 40cm${\times}$3cm, and 40cm${\times}$5cm. They were installed at five positions, spaced 45cm at a height of 5cm from the floor. The exhaust fan was designed for its operating voltage to be set to five steps(100V, 130V, 150V, 180V and 220V) in order to control its air flow rates. When the size and position of each supply opening were changed with the wind velocity of the exhaust fan set to the step 5, the ventilation rates were measured and analyzed by the concentration decay method of tracer gas method, in order to present an efficient mechanical ventilation system. The results of the study revealed that the ventilations rates would increase in the presence of supply openings, compared to the absence of supply openings, and that the larger the size of the supply opening, the more the ventilation rates. Therefore, it was found necessary to take air supply into consideration.

• Journal of The Korean Society of Clinical Toxicology
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• v.6 no.1
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• pp.32-36
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• 2008

Purpose: The major complication of acute organophosphate (OP) poisoning is respiratory failure as a result of cholinergic toxicity. Many clinicians find it difficult to predict the optimal time to initiate mechanical ventilation (MV) weaning, and as a result have tended to provide a prolonged ventilator support period. The purpose of this study is to determine any clinical predictors based on patients characteristics and laboratory findings to assist in the optimal timing of mechanical ventilator weaning. Methods: We reviewed medical and intensive care records of 44 patients with acute OP poisoning who required mechanical ventilation admitted to medical intensive care unit between July 1998 and June 2007. Patient information regarding the poisoning, clinical data and demographic features, APACHE II score, laboratory data, and serial cholinesterase (chE) levels were collected. Base on the time period of MV, the patients were divided into two groups: early group (wean time < 7 days, n = 28) and delayed group (${\geq}$ 7 days, n = 16). Patients were assessed for any clinical characteristics and predictors associated with the MV weaning period. Results: During the study period, 44 patients were enrolled in this study. We obtained the sensitivity and specificity values of predictors in the late weaning group. APACHE II score and a reciprocal convert of hypoxic index but specificity (83.8%) is only APACHE II score. Also, the chE concentration (rho = -0.517, p = 0.026) and APACHE II score (rho = 0.827, p < 0.001) correlated with a longer mechanical ventilation duration. Conclusion: In patients with acute OP poisoning who required mechanical ventilation, the APACHE II scoring system on a point scale of less than 17 and decrements in cholinesterase levels on 1-3 days were good predictors of delayed MV weaning.

• Journal of Trauma and Injury
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• v.33 no.4
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• pp.264-268
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• 2020

A 55-year-old man underwent emergent sternotomy due to cardiac tamponade occurring just after an accidental fall from a 10-m height. Tricuspid valve regurgitation was found on echocardiography while he was on mechanical ventilation after the operation. The patient was weaned successfully from mechanical ventilation after tricuspid valve repair under cardiopulmonary bypass. Traumatic tricuspid valve regurgitation is a rare blunt chest injury and its symptoms occur late. Tricuspid regurgitation should be considered as a reason for failure to wean from mechanical ventilation after blunt cardiac trauma.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.7
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• pp.402-408
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• 2009

In this paper, the effects of ventilation and humidification on thermal comfort and indoor air quality(IAQ) were evaluated in a classroom when a heat pump system was operated in winter. Thermal comfort parameters, such as temperature, relative humidity, globe temperature and air velocity, were measured at 9 points in the classroom. The concentration of $CO_2$ and total suspended particles(TSP) in the classroom were measured in order to analyze IAQ. Temperature distribution in the classroom was decreased by $2{\sim}5^{\circ}C$ when the ventilation system and the humidifier were operated. When the relative humidity was adjusted to 60% by operating the humidifier and the ventilation system, the predicted mean vote(PMV) in the classroom was within the comfortable range of $-0.5{\sim}0.5$. When the ventilation system was operated, the average concentration of $CO_2$ and TSP were decreased by 645 ppm and 0.17 $mg/m^3$, respectively. This paper suggests the humidification and ventilation conditions to maintain the comfortable environment in the school classroom in winter experimentally.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.517-522
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• 2008

Ventilation rate and filter were selected to simultaneously satisfy indoor air quality and minimize energy consumption in residential housing. The concentrations of indoor particles were calculated using an adapted mass balance model for various ventilation airflow rates. To satisfy the guidelines for indoor concentrations of particles, the minimum ventilation rates of 1.0/h, 0.6/h and 0.4/h were required for MERV11, MERV13 and MERV14, respectively. And the fan power consumptions induced by ducts, a heat exchanger and a filter were calculated for various ventilation airflow rates. The increase in the ventilation rate caused a dramatic increase in the power consumption, but the filter performance did not have much of an effect on the fan power for ventilation airflow rates lower than 0.4/h. The use of the ventilation filter of MERV 14 was suggested at a ventilation rate of 0.4/h when the fan power consumptions were considered in addition to the indoor concentrations of particles and $CO_2$. The use of the MERV14 filter at a ventilation rate of 0.6/h could be more effective than the additional use of an indoor air cleaner when the residential housing unit was ventilated.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.6 s.237
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• pp.711-721
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• 2005

In order to design of emergency ventilation systems, the smoke movements in tunnel fire with natural and forced ventilation were investigated. Reduced-scale experiments were carried out under the Froude scaling with novel fire source consisting many wicks. Temperature profiles were measured under the ceiling and vertical direction along the center of the tunnel and poisonous gases were measured at emergency exit point in the natural ventilation case. In forced ventilation, temperature profiles were measured with various flow rate to obtain critical velocity. The results showed that the interval of emergency exit having 225m was estimated reasonably through the measurements of temperature variation and poisonous gas in the natural ventilation. In the case of forced ventilation, the temperature distribution near fire source is remarkably different from that of natural ventilation. Also, the critical velocity to prevent upstream smoke flow has the range of 0.57m/s between 0.64m/s. Finally, it was also identified that although the increase of flow rate can suppress the backward flow of smoke to upstream direction, brings about the increase of flame intensity near stoichiometric fuel/air ratio.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.502-507
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• 2009

Trend of mechanical ventilation system applied to apartment house is introduced and feasibility study on installation of the individual room control ventilation as energy-saving method is carried out through field experiment. While initial cost of installation for the individual room control ventilation increases, the running cost is lower than the individual household control ventilation due to automatic flow rate control and reduction of fan power, and the management cost also decreases due to extension of use life of components. As the results of field experiment on $115m^2$-type apartment house, the individual room control ventilation could save the amount of 1,459.5Wh/day when compared with the individual room control ventilation