• Journal of the Korean Solar Energy Society
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• v.30 no.4
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• pp.36-42
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• 2010

본 논문은 태양열이용 냉난방시스템 중에서 실제로 액체흡수제를 재생하는 재생탑 내의 충진층에 있어서의 열 및 물질전달의 실험치와 이론적 해석에 의한 결과치와의 비교를 나타내고 있다.특히 물질전달의 극대화를 위하여 충진층 내에서 공기와 흡수제의 접촉면적을 크게 할 필요가 있는데,이를 위해서 본 실험에서는 직경이 3cm인 플라스틱제 충진재를 사용하였으며, 흡수제로는 저농도의 염화리튬 수용액이 사용 되었다. 충진층 내에서의 최적 높이를 예측하기 위하여 해석의 모델인 실험장치를 직접 제작하여 실험을 수행하였고, 이론 해석에 있어서 체적 열전달을 고려한 정상상태를 모델화하여 해석하였다. 이 결과, 충진층 내에서 실험치와 이론적인 계산치가 잘 일치함을 알 수 있었으며, 충진층의 높이가 2m 이상인 경우에는 높이에 따른 재생량의 차이가 없어서 없음을 알 수 있었다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.9
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• pp.516-521
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• 2013

In the present study, the performances of a fin-tube evaporator and three PF evaporators for a heat pump dryer were experimentally investigated. Among the tested evaporators, the PF3 type evaporator showed the highest values of heat transfer capacity and dehumidification performance, while the fin-tube evaporator had the lowest values. PF3 showed better performance compared to PF1 and PF2, due to the large pin pitch, which leads to more draining for dehumidified water. Also, the $45^{\circ}$ inclined PF evaporator presented better performance than that of the $90^{\circ}$ inclined PF evaporator, owing to its easier draining characteristics. The effect of air velocity was revealed to be quite large. When the air velocity increased by 20%, the heat transfer capacity and dehumidification performance increased 43%/11%, 48%/13% and 54%/23% for PF1, PF2 and PF3, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.288-296
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• 2019

Radiation cooling has used ceilings or floors as cooling surfaces. In such cases, to avoid moisture condensation on the surface, the surface temperature needs be higher than the dew point temperature or an additional dehumidifier is added. In this study, with a goal for residential application, intentional moisture condensation on the cooling surface was attempted, which increased the cooling capacity and improved the indoor comfortness. This method included two separate refrigeration cycles - convection-type dehumidifying cycle and the panel cooling cycle. Test results on the panel cooling cycle showed that, at the standard outdoor ($35^{\circ}C/24^{\circ}C$) and indoor ($27^{\circ}C/19.5^{\circ}C$) condition, the refrigerant flow rate was 8.8 kg/h, condensation temperature was $51^{\circ}C$, evaporation temperature was $8.8^{\circ}C$, cooling capacity was 376 W and COP was 1.75. Furthermore, the panel temperature was uniform within $1^{\circ}C$ (between $13^{\circ}C$ and $14^{\circ}C$). As the relative humidity decreased, the cooling capacity decreased. However, the power consumption remained approximately constant. In the convection-type dehumidification cycle, the refrigerant flow rate was 21.1 kg/h, condensation temperature was $61^{\circ}C$, evaporation temperature was $5.0^{\circ}C$, cooling capacity was 949 W and COP was 2.11 at the standard air condition. When both the radiation panel cooling and the dehumidification cycle operated simultaneously, the cooling capacity of the radiation panel cycle was 333 W and that of the dehumidification cycle was 894 W, and the COP was 1.89. As the fan flow rate decreased, both the cooling capacity of the radiation panel and the dehumidification cycle decreased, with that of the dehumidification cycle decreasing at a higher rate. Finally, a possible control logic depending on the change of the cooling load was proposed based on the results of the present study.

• Journal of Bio-Environment Control
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• v.7 no.3
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• pp.237-245
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• 1998

Greenhouse crop production under critical summer climate In Korea has considerable difficulties because of high temperature and relative humidity. In this study, some water pipes were tested as a means of the dehumidification and increment of evaporative cooling efficiency. As a result of heat transfer characteristic analysis, overall heat transfer coefficient of copper pipe was larger than steel pipe, and estimated values were smaller than measured values. The condensed quantities of vapor were not significantly different between copper pipe and steel pipe, however dehumidifying effect by the water pipes was significantly large. It was estimated based on the results that the evaporative cooling system by the water pipe will be able to increase the evaporative cooling efficiency of about 48%, and decrease the temperature of about 1.3$^{\circ}C$.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.29 no.8
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• pp.50-58
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• 2000

실내공기질과 환기풍량 그리고 HVAC 관련 비틀은 서로 밀접한 관계가 있다. 공기대 공기 열 교환기를 이용하여 급기를 가열 또는 냉각함으로써 제습이나 가습의 필요성을 크게 줄일 수 있다. HVAC 설치 및 운전비용을 결정하는 가장 중요한 요소는 소요환기량, 기후변수, 열교환기 성능변수 그리고 운전기간 등이다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.419-423
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• 2008

엔진 성능의 시험에 있어서 작동유체인 압축공기의 물성중 수분은 매우 중요한 부분으로, 엔진의 작동과 성능에 영향을 미치는 대표적인 요인이다. 특히 고공환경 시험에서는 습도의 조건에 따라 성능의 차이가 커지므로 엔진의 정확한 성능과 운용성을 파악하는데 작동유체인 압축공기중에 포함된 수분의 조건은 대단히 중요하다. 압축상태인 작동유체의 수분 함유량을 고공의 조건과 같은 $-40^{\circ}C$ 이하의 이슬점(Dew Point) 상태로 제습 하기 위한 장치인 흡착식 Air Dryer의 개발을 위해 흡착과정 및 재생과정에 대한 이해와 흡착제의 흡착효율을 극대화하고, 재생비용을 최소화하여 에너지를 저감 할 수 있는 Air Dryer System에 대하여 기술한다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.429-434
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• 2011

Bulk cargo loaded into ship can be damaged by various kinds reasons. This paper aims to analyze about cargo damage of coil carrier ship due to condensation. Condensation is the formation of liquid drops of water from water vapor. Condensation consists of small drops of water which form when warm water vapour or steam touches a cold surface such as a window. In general, condensation have occurred by temperature difference at large building and ship's tank. It is phenomenon that can occur often to oceangoing vessel moving temperature difference places in similar time. This paper proposes a new method using dehumidification device and fan heater to prevent bulk cargo damage of coil carrier ship from condensation.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.136-146
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• 2019

A solid oxide fuel cell (SOFC) based hybrid desiccant cooling system model is developed to study the effect of fuel utilization rate of the SOFC on the reduction of energy consumption and $CO_2$ emission. The SOFC-based hybrid desiccant cooling system consists of an SOFC system and a Hybrid desiccant cooling system (HDCS). The SOFC system includes a stack and balance of plant (BOP), and HDCS. The HDCS consists of desiccant rotor, indirect evaporative cooler, electric heat pump (EHP), and heat exchangers. In this study, using energy load data of a commercial office building and SOFC-based HDCS model, the amount of ton of oil equivalent (TOE) and ton of $CO_2$ ($tCO_2$) are calculated and compared with the TOE and $tCO_2$ generation of the EHP using grid electricity.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.154-156
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• 2008

A prototype of the desiccant cooling system with a regenerative evaporative cooler was built and tested for the performance evaluation. The regenerative evaporative cooler is to cool a stream of air using evaporative cooling effect without an inc6rease in the humidity ratio. It is comprised of multiple pairs of dry and wet channels and the evaporation water is supplied only to the wet channels. By redirecting a portion of the air flown out of the dry channel into the wet channel, the air can be cooled down to a temperature lower than its inlet wet-bulb temperature at the outlet end of the dry channels. Incorporating a regenerative evaporative cooler eliminates the need for deep dehumidification in the desiccant rotor that is necessary to achieve low air temperature in the system with a direct evaporative cooler. Subsequently, the regenerative evaporative cooler enables the use of low temperature heat source to regenerate the dehumidifier permitting the desiccant cooling system more beneficial compared with other thermal driven air conditioners. At the ARI condition with the regeneration temperature of $60^{\circ}C$, the prototype showed the cooling capacity of 4.4 kW and COP of 0.75.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.5
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• pp.208-215
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• 2016

This study was conducted to improve the performance of low-temperature vacuum dryer by applying desiccant to cold trap. Performance evaluation was carried out using several desiccants. The amounts of absorption and diffusivity were measured based on analytic model. Results of desiccant performance evaluation revealed that silica-gel had the most excellent performance for conditions of low-temperature vacuum drying process. Silica-gel was applied to cold trap for evaluating the drying performance. The experiment results showed that the drying time was extended as the thickness of sample was increased due to increased heat and mass transfer resistance of drying sample. In addition, as heating plate temperature was increased, drying time was decreased due to increased evaporation pressure of drying sample. Furthermore, drying time with desiccant was decreased approximately 20% than that without desiccant.