• Journal of Korean Biological Nursing Science
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• v.11 no.1
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• pp.92-98
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• 2009

Purpose: This study was aimed to investigate the colony counts by different disinfecting processes and duration of the operation for humidifiers in an intensive care unit (ICU) in Busan. Method: The four steps of disinfecting process were taken with four different humidifiers according to the use of disinfectant (1:100 $Deconex^{(R)}$ 50FF/nothing) and refilling water (tap water/distilled water). First, the colony counts using water sample from wick was conducted at 0 hr, 24 hr, and 48 hr respectively after turning on the humidifiers. Next, the colony counts using waterdrop from the outlet was done at 0 hr, 24 hr, 48 hr, and 72 hr respectively after turning on the humidifiers. Result: No colony was counted after disinfecting with 1:100 $Deconex^{(R)}$ 50FF until 72 hr after turning on the humidifiers. However, without disinfecting with $Deconex^{(R)}$ 50FF, the colony count was increased in the humidifiers from 24 hr after turning on the humidifiers. The result was the same regardless of the refilling water. Conclusion: According to the results, the study found that disinfection of humidifiers in the ICUs with 1:100 $Deconex^{(R)}$ 50FF every 72 hr is effective to remove general bacteria.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.1
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• pp.20-26
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• 2016

This study investigated noise characteristics of air cleaners and humidifiers in terms of frequency domains and measurement directions. Noise levels of 31 air cleaners and 36 humidifiers were measured in an anechoic chamber according to the related group standards. As for air cleaners, 5 receiving points of 1 m off from front, rear, left, right and top surfaces of the product were considered. In case of humidifiers, 4 receiving points without the rear position were considered in the same manner as air cleaners. In each case, A-weighted equivalent continuous sound level was measured three times for 1 min. As a results, most of the measured air cleaners and humidifiers showed the highest noise levels at top directions due to the air ventilating location. In case of air cleaners, averaged noise levels of top and rear positions were 49.9 and 48.2 dB(A), respectively, whereas averaged noise level of other positions was all 45.2 dB(A). In case of humidifiers, averaged noise level of top position was 44.1 dB(A) whereas averaged noise levels of other positions were 38.7 to 39.1 dB(A). In addition, high frequency content of 1 kHz and 3.15 kHz to 4 kHz for air cleaners and middle frequency content of 500 Hz to 1.6 kHz for humidifiers showed significant contribution to determination of overall noise levels with correlation coefficient of 0.9 and above.

• Journal of Environmental Health Sciences
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• v.39 no.2
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• pp.105-116
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• 2013

Background: In Korea, there is low awareness of the respiratory health problems caused by the use of humidifiers, leading to a lack of governmental measures. Objectives: The objectives of this study were to review cases of varying degrees of humidifier lung and fever in connection with the use of humidifiers and to summarize the probable environmental agents causing these cases. Methods: We searched all articles reporting on humidifier lung, humidifier fever, and humidifier diseases caused by the use of a humidifier both at home and in the workplace. Results: We summarized a number of cases of varying degrees of respiratory diseases resulting from inhalation of water mist of humidifiers containing various species of bacteria and fungi and their toxins. Type of respiratory disease connected with humidifier lung includes interstitial pneumonitis, hypersensitivity pneumonitis, fever and several respiratory symptoms. Non-tuberculous mycobacteria (NTM), Actinomycetes, endotoxins and contaminated humidifier water were the most commonly suspected probable environmental agents causing humidifier lung. In Korea, the use of humidifier biocide is suspected as a likely cause of fatal lung injury including death and lung transplantation. Conclusion: Governmental policy should be devised and measures including a national surveillance system should be taken to prevent humidifier lung caused by the use of humidifiers.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.429-432
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• 2006

Characteristics of heat and water transfer in gas-to-gas membrane humidifiers have been experimentally investigated for various humidity rod flow rates of gas and for different thickness of Nafion membrane. The results emphasizes the importance of flow velocity for both water and heat transfer. Also, the effect of membrane thickness has been revealed to be significant to water transfer especially for unsaturated flows, while the significance of membrane thickness is minimal to heat transfer.

• Environmental Analysis Health and Toxicology
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• v.27
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• pp.4.1-4.2
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• 2012

• Environmental Analysis Health and Toxicology
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• v.27
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• pp.1.1-1.3
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• 2012

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.931-937
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• 2012

In this study, we assessed environmental impacts of compound humidifiers using environmental life cycle assessment and presented the ways to improvements in energy consumption of them. We found eco-design parameters and $CO_2$-eq emissions in each stage of raw material acquisition, manufacturing, transportation, use and disuse in life cycle of the compound humidifiers. The highest $CO_2$ emission is found to be in the stage of use among all stages of life cycle, which is mainly due to power consumption in thermal heating of heating coil for sterilization during humidification. The power consumption and $CO_2$ emission in the stage of use can be reduced to 1/4 and 1/3 at the highest estimate through improvement of sterilization method, respectively. We suggested the replacement of conventional thermal heating coil by ultra violet light-emitting diodes (UV-LED) for sterilization and then presented the experimental results on the sterilization effects of UV-LEDs.

• Journal of Bio-Environment Control
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• v.12 no.1
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• pp.12-16
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• 2003

The effect of humidifying methods on the mean size of droplets ejected from humidifier and distributions of relative humidity in a graft-taking enhancement system (GTES) was investigated. The mean sizes of droplets ejected from an ultrasonic humidifier and a steam humidifier with electrodes were 7.58$\pm$0.14 and 9.01$\pm$0.06 $\mu$m, respectively. Assuming that the particles ejected from humidifiers were mutually combined with distance, the mean diameter of droplets became larger as the distance apart from the outlet of humidifiers increased. When the relative humidity in GRS was controlled at 90％ using the ultrasonic humidifiers, the average relative humidity at the height of 0.4, 1.1 and 1.8 m were 92.1$\pm$5.3, 90.9$\pm$5.6, and 89.7$\pm$6.8%, respectively. However, the average relative humidity using the steam humidifier with electrodes showed 93.4 $\pm$5.4, 90.7$\pm$5.9, and 89.3$\pm$7.0%, respectively. Therefore, it was concluded that humidification by ultrasonic humidifier would be appropriate for the uniform distribution of relative humidity in GTES.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.13-18
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• 2016

Humidifiers are used to control indoor humidity. Element-type humidifiers have the advantages of simple structure and low energy consumption, and Japanese products have been widely used for the humidifying elements. In this study, a new humidifying element made of cellulose and PET was developed, and the performance was compared with that of a Japanese element. The mass transfer rates and pressure drops were measured for an element installed at the entrance of a suction-type wind tunnel. The humidification efficiency of the new element was 2 to 4% greater and the pressure drop was 23 to 32% smaller compared to the Japanese element. The mass transfer effectiveness ($j_m/f$) of the new element is also 5 to 28% higher. However, the water absorption capacity was smaller than that of the Japanese element, meaning further development is needed.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.345-348
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• 2009

Maintaining proper membrane humidity is crucial to ensure optimal operation of a PEMFC system. A gas-to-gas membrane humidifier is popular technology for external humidification of PEMFC reactant gases. Characteristics of heat and water transfer in shell-and-tube Nafion membrane humidifiers has been experimentally investigated for various dry side inlet temperature of membrane humidifier. The results show that heat flux decreases linearly with dry side inlet temperature of membrane humidifier. The water flux through the membrane varies nonlinearly with the temperature elevation.