• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.2
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• pp.55-63
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• 2013

For a large-scale semiconductor manufacturing clean room, the energy consumed in an outdoor air conditioning system to heat, humidify, cool and dehumidify incoming outdoor air is very large. In particular, the energy requirement to humidify outdoor air in the winter season is generally known to be high. Recently, in order to overcome the high energy consumption nature of a steam generator in a conventional steam humidification type outdoor air conditioning system, an air washer is often introduced instead of the steam generator in the outdoor air conditioning system, which can be called a water spray humidification type outdoor air conditioning system. Therefore, the assessment and comparison of the annual energy consumed in the steam humidification type and the water spray humidification type outdoor air conditioning systems deserves to be examined in order to reduce the outdoor air conditioning load of a clean room. In the present study, a numerical analysis was conducted to obtain the annual electric power consumption of the two outdoor air conditioning systems. It was shown from the comparison of the numerical results that the water spray humidification type outdoor air conditioning system can reduce about 30% of annual electric power consumption of the steam humidification type outdoor air conditioning system.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.6
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• pp.547-552
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• 2010

In this study, we suggested an integrated humidification system for a fuel cell electric vehicle (FCEV) as an efficient method of humidification under the various driving condition of the fuel cell vehicle and system. It is improving air humidification system combined the existing membrane humidifier and water injection. As a result, we verified it through experiments and the vehicle test and could get a result of improvement of humidification performance. The results show that an integrated humidification system is a useful method for FCEV applications.

• Korean Chemical Engineering Research
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• v.55 no.4
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• pp.478-482
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• 2017

Humidity control of proton exchange membrane fuel cell(PEMFC) is very important control condition during driving. In terms of water management, low humidification conditions are advantageous, and high humidification is advantageous in terms of drainage utilization and energy efficiency. In this study, the characteristics of outlet water in low humidification and high humidification process were studied in terms of utilization of discharged water. Since the impurities in the effluent are generated during the degradation of the membrane and the electrode assembly(MEA), degradation of the MEA under low humidification and high humidification conditions was also studied. The rate of radical generation was high at low humidification condition of the anode RH 0%, which showed that it was the main cause of the degradation of the polymer membrane. Analysis of effluent showed low concentration of fluoride ion concentration of about 20 ppb at high humidification (both electrodes RH 100%) and 0.6 V, which was enough to be used as the feed water for electrolysis. Very low concentration of platinum below 0.2 ppb was detected in the condensate discharged from the high humidification condition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1249-1255
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• 2011

In modern large-scale semiconductor manufacturing clean rooms, the energy consumed by the outdoor air-conditioning system during heating, humidification, cooling, and dehumidification of the incoming outdoor air represents about 45% of the total air-conditioning load required to maintain a clean-room environment. In particular, the energy required for humidification of the outdoor air in winter is very high. Therefore, evaluation and comparison of the energy consumption in key humidification systems, viz., steam-humidification and water-spray-humidification systems, used in outdoor air-conditioning systems would be useful to reduce the outdoor air-conditioning load in clean rooms. In the present study, an experiment with an outdoor air flow of 1000 $m^3$/h was conducted to compare the air-conditioning process and energy consumption in outdoor air-conditioning systems with electrodeboiler steam humidifiers and air-washer water spray humidification systems. The experimental results showed that the water-spray-humidification-type outdoor air-conditioning system consumed less electrical power than did the steam-humidification-type system and was more energy efficient during winter.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.337-344
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• 2011

The humidification of reactant gases is crucial for efficiently operating PEM (polymer electrolyte membrane) fuel cell systems and for improving the durability of these systems. The recycle of the energy and water vapor of exhaust gas improves the system performance especially in the case of automotive application. The available humidification methods are steam injection, nozzle spray, humidification by enthalpy wheel, membrane humidifier, etc. However, these methods do not satisfy certain requirements such as compact design, efficient operation and control. In this study, a hybrid humidification system consisting of a membrane humidifier and exhaust-air recirculation units was developed and the humidification performance of this hybrid humidifier was analyzed. Finally, a new practical method for optimal design of PEM-fuel-cell humidification system is proposed.

• Proceedings of the Korean Society of Crop Science Conference
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• 1998.04a
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• pp.123-124
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• 1998

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.491-498
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• 2010

Humidification of PEM fuel cells is necessary for enhancing their performance and lifetime. In this study, a humidification system was designed and tested; the system includes an air-supply tube (inner diameter: 75 mm) through which a nozzle can be directly inserted and a cyclonic separator for the removal of water droplets. Three types of nozzles were employed to study the influence of injection pressure, air flow rate, and spray direction on the humidification performance. To evaluate the humidification performance, the concept of humidification efficiency was defined. In the absence of an external heat source, latent heat for evaporation will be supplied by the own enthalpies of water and air. Thus, the amount of water sprayed from the nozzle is the most critical factor affecting the humidification efficiency. Water droplets were efficiently removed by a cyclonic separator, but re-entrainment occurred at high air flow rates. The absolute humidity and humidification efficiency were $21.29\;kJ/kg_{da}$ and 86.57%, respectively, under the following conditions: nozzle type PJ24; spray direction angle $90^{\circ}$; injection pressure 1200 kPa; air flow rate 6000 Nlpm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.732-740
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• 2019

Evaporative humidification using a humidifying element is widely used for humidification of a building or a data center. The performance of a humidifying element is commonly expressed as humidification efficiency, which is used independent of air temperature, humidity and water temperature. In this study, a series of tests were conducted at two air conditions (data center and commercial building) using two different humidifying elements (cellulose/PET and Glasdek) changing the frontal air velocity and water temperature. Results showed that the measured humidification efficiency was dependent on the air condition and water temperature. In fact, even dehumidification occurred at the inlet of the humidifying element at the air condition of commercial building. The reason was due to the inlet water temperature, which was lower than the dew point air temperature. As the difference between the inlet water and the dew point air temperature increased, the humidification efficiency decreased. This suggest that proper thermal model should account for the inlet region, where the amount of moisture transfer may be different from the other part of the humidification element. A simple analysis on the thermal performance of the cellulose/PET humidification element showed that the Sherwood number was adequately predicted, whereas the friction factor was ovepredicted, probably due to the simplification of the channel geometry and the neglection of the water film on the element surface.

• Journal of the Korean Wood Science and Technology
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• v.20 no.3
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• pp.29-37
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• 1992

This research was carried out to investigate the effects of cyclic humidification on the dimensional stability of particleboard manufactured according the three specific gravity levels and com-ply fabricated with a core of particleboard and veneer or plywood as the face and back materials. Both the particleboard and com-ply were subjected to four cycles of 50-90-50% relative humidity. The results are summarized as follows: Particleboard and com-ply followed a clear pattern of increasing dimensions and weight on the adsorption cycle and decreasing dimensions and weight on the humidification cycle. After the fourth cycle, the dimensions and weight of both particleboard and com-ply were greater than those originally measured. The greater part of increase in occurred during the first humidification cycle. The specific gravity of particleboard has a significant effect thickness and volume change. The dimensional stability of com-ply was better than that of particleboard. In addition, the dimensional stability of com-ply bonded with plywood was better than that of com-ply bonded with veneer.

• Child Health Nursing Research
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• v.17 no.2
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• pp.145-152
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• 2011

Purpose: To evaluate the efficacy of Optimal humidification during Nasal Continuous Positive Airway Pressure (nCPAP) for Extremely Low Birth Weight Infant (ELBWI). Methods: The study design was a pre-test-post-test nonequivalent nonsynchronized quasi-experimental design. The participants were 218 ELBWI on nCPAP (experimental group: 102 and control group: 116). Data collection was conducted from January 2005 to April 2010. In order to measure and analyze the nCPAP duration, reintubation and nasal condition, Chi-square test and t-test were used. Results: Hypothesis 1, that the duration with nCPAP in the experimental group is longer than that of the control group and hypothesis 2-3, that the rate of reintubation and nasal problems in the experimental group are lower than the control group, were all supported as there were statistically significant differences between two groups. Conclusion: The findings suggest that the Optimal humidification in this study is an efficient intervention because it helps increase the last time of nCPAP with ELBWI and minimize complications. It is expected that Optimal humidification is beneficial and helpful in preventing and caring for respiratory problems in these infants.