• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.8-8
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• 2004

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.104-104
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• 2003

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.217-217
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• 2003

• Journal of the Korean Society for Precision Engineering
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• v.28 no.1
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• pp.108-114
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• 2011

Steam reformer was organized with steam reforming process and CO removing process. The steam reforming process needed high temperature, 600~900 $^{\circ}C$, for catalytic-reaction which was extract of hydrogen from steam and hydrocarbon. The effects of the evaporator configuration on its heat transfer characteristics were investigated both experimentally and numerically to pursue the miniaturization. In this study, three configurations were considered where the different structures were tested; empty, embossing and mesh filled. For the comparison of heat transfer performance of shape evaporator disk, numerical analysis using SC-Tetra code and experiment were carried out. In case of reformer system design, it should be considered heat transfer rate, differential pressure and fluid flow direction.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.5
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• pp.328-335
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• 2010

The purpose of this study is to make an analysis of influence on the cooling capacity and COP of a desiccant cooling system with a regenerative evaporative cooler when a direct evaporative cooler was applied to the inlet of regeneration process of this system. We used cycle simulation in order to analyze the performance of this system. From the cycle simulation, we knew that the optimal rotation time of desiccant rotor was between 160s and 220s and hardly ever affected cooling capacity of desiccant cooling system when this system was operated at the outdoor air condition of $35^{\circ}$ and 40% RH and low regeneration temperature of $60^{\circ}$. Also there was optimal area ratio of regeneration to dehumidification between 0.7 and 1.0. Our results showed that it had a small effect on the system’s cooling capacity to install direct evaporative cooler at the inlet of regeneration process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.3
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• pp.216-222
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• 2005

An experimental investigation was executed to determine the capacity degradation due to fin conduction and non-uniform refrigerant distribution in a multi-path evaporator with cross-counter flow. The finned-tube evaporator, which had a three-path and three-depth-row, was tested by controlling inlet quality, exit pressure, and exit superheat for each refrigerant path. The capacity reduction due to superheat unbalance between each path was as much as $25\%$ for non-cutting evaporator, even when the overall evaporator superheat was kept at a target value of $5.6^{\circ}C$. It indicates that the internal heat transfer within the evaporator assembly causes the partial capacity drop. The capacity of cutting-evaporator with respect to non-cutting evaporator was enhanced according to the increment of air flow rate when superheat or superheat unbalance increased.

• Membrane Journal
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• v.6 no.1
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• pp.37-43
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• 1996

Chitosan composite membranes were prepared by casting chitosan solution onto porous polysulfone ultrafiltration membrane. Composite membranes to separate water from aq. ethanol solution were chemically crosslinked by using various crosslinking agent, glyoxal, terephthalaldehyde and glutaraldehyde. The morphology of surface crosslinked chitosan composite membranes were examined by scanning electron microscopy. ATR-FTIR was employed to confirm the crosslinking mechanism of surface crosslinked chitosan composite membranes. In the case of glutaraldehyde, optimum separation factor and decreasing trend of flux were shown.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.04b
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• pp.3-10
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• 1997

제염농축공정은 증류, 증발법을 일반적으로 사용하나, 에너지 절약차원에서 전기투석 (Electro dialysis)장치를 증발기 선단에 도입한 복합공정을 국내에서도 사용하고 있는 실정이다. 그러나, 전기투석장치는 전기적인 소모와 막의 재생, 교체처리비가 문제점이 되므로 역삼투 장치를 제염농축 공정 최선단에 도입한 복합공정을 이용할 경우 전기 투석 및 증발 복합공정에 비해 40%의 에너지 절감 효과를 기대할 수 있다. 이와 같은 장점에도 불구하고 역삼투 공정은 공급용액의 삼투압보다 큰 적용압력을 막표면에 가하여 물질분리를 수행하므로 농축공정에서 유발되는 배제액 농도의 상승은 삼투압의 증가를 일으켜 실적적용압력의 효과를 떨어뜨리게 되며 결과적으로 농축효과를 감소시키게 된다. 본 연구에서는 효과적인 염농축 공정을 위하여 막모듈 투과부에 고농도 삼투압 감소액(osmotic sink solution)을 향류식(막투과흐름을 맞받아치며 흐르는 방식)으로 유입시키는 향류식 역삼투 (counter-current reverse osmosis, CCRO) 나권형 모듈을 고안 제작하였으며, 제작된 모듈을 기존 역삼투 공정과 향류식 염삼투 공정에 적용하여 염농축도의 성능을 상호 비교하고 염농축에 관계되는 공급농도, 공급유량, 투과유량, 배제유량, 향류 유입유량, 압력구배, 삼투압차 및 농축단수 등의 인자들을 이용하여 두 공정에 대한 염농축 분리조작의 제반조건과 제작된 모듈 내의 농축관련 특성을 실험 및 수치적으로 비교, 고찰하였다.

• Journal of the Korean Institute of Gas
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• v.14 no.1
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• pp.1-7
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• 2010

In this paper, cycle performance analysis of $NH_3-CO_2$(R717-R744) two-stage cascade refrigeration system is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include subcooling and superheating degree, compressor efficiency, and condensing and evaporating temperature in the ammonia(R717) high temperature cycle and the carbon dioxide low temperature cycle. The main results were summarized as follows : The COP of two-stage cascade refrigeration system increases with the increasing subcooling degree, but decreases with the increasing superheating degree. The COP of two-stage cascade refrigeration system decreases with the increasing condensing temperature, but increases with the increasing evaporating temperature. And the COP of two-stage cascade refrigeration system increases with increasing the compressor efficiency. Therefore, superheating and subcoolng degree, compressor efficiency, and evaporating and condensing temperature of $NH_3-CO_2$(R717-R744) two-stage cascade refrigeration system have an effect on the COP of this system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.607-613
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• 2010

A seawater distiller, in which the waste heat from a portable electric generator was used, with a multiple-effect diffusion still was designed. The waste gas from small generators commonly used in islands has not yet been used because it has less thermal energy; however, this waste gas can be used as a heat source for small-capacity distillers and as an additional heat source for solar stills. The proposed distiller comprises a series of closely spaced parallel partitions that are placed in contact with saline-soaked wicks. In the distiller, evaporation and condensation processes are repeated to recycle the thermal energy for increasing the distillate productivity. Experimental results show that the proposed distiller with only one-effect still can produce at least 6.7 kg/day of distilled water; the proposed distiller with a ten-effect still is expected to produce 43 kg/day of distilled water. This amount of distillate is approximately four times the maximum daily productivity of the solar stills, as determined in outdoor experiments.