• Journal of Advanced Marine Engineering and Technology
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• 제28권2호
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• pp.252-262
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• 2004

A model of simultaneous heat and mass transfer process in absorption of refrigerant vapor into a lithium bromide solution of water-cooled vertical plate absorber. which was considered to the change of refrigerant vapor pressure along the plate width direction. was developed to evaluate the compactness of plate absorber and supply basis data for optimal design of plate absorber. The effects of plate interval as well as the effect of capacity for one piece of plate absorber on plate absorber size such as plate height. plate heating area and plate absorber volume have been investigated. It is confirmed that there is exist an optimal plate interval minimizing plate absorber volume. And the smaller capacity for one piece of plate absorber. the smaller plate absorber volume is obtained.

• 한국태양에너지학회 논문집
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• 제23권4호
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• pp.45-54
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• 2003

For cooling of double effect absorption heat pump system of solar heating source, analysis of thermodynamic design data has been done to find the property of Libr-water + ethylene Glycol mixture for working fluid by computer simulation. Derived thermodynamic design data, enthalpy based coefficient of performance and flow ratio for possible combinations of operating temperature for water - LiBr and Ethylene Glycol mixture ($H_2O$ : CHO ratio 10:1 by mole) by computer simulation are done. The obtained results, COP and mass flow ratio of the water - lithium bromide - ethylene glycol system, are compared with data for the water-Libr pair solution.

• 한국태양에너지학회 논문집
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• 제22권4호
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• pp.51-61
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• 2002

Analysis of thermodynamic design data of double effect solar absorption heat pump system for heating has been done to find the property of Libr-water + ethylene Glycol mixture for working fluid by computer simulation. Derived thermodynamic design data. enthalpy based coefficient of performance and flow ratio for possible combinations of operating temperature for water - LiBr and Ethylene Glycol mixture (H2O: CHO ratio 10:1 by mole) by computer simulation. The obtained results, COP and mass flow ratio of the water-lithium bromide-ethylene glycol system, are compared with data for the water-Libr pair solution.

• International Journal of Air-Conditioning and Refrigeration
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• 제6권
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• pp.56-66
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• 1998

The absorption process of water vapor in a liquid film is an important process in LiBr-Water absorption system. The composition of the gas phase, in which a non-absorbable gas is combined with the absorbate, influences the transport characteristics. In the present work, the absorption processes of water vapor into aqueous solutions of lithium bromide in the presence of non-absorbable gas are investigated. The continuity, momentum, energy and diffusion equations for the solution film and gas are formulated in integral forms and solved numerically. It is found that the mass transfer resistance in gas phase increases with the concentration of non-absorbable gas. However the primary resistance to mass transfer is in the liquid phase. As the concentration of non-absorbable gas in the absorbate increases, the interfacial temperature and concentration of absorbate in solution decrease, which results in the reduction of absorption rate. The reduction of mass transfer rate is found to be significant for the addition of a small amount of non-absorbable gas to the pure vapor, especially at the outlet of tube where the non-absorbable gas accumulates. At higher non-absorbable gas concentration, the decrease of absorption rate seems to be linear to the concentration of non-absorbable gas.

• 한국가스학회지
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• 제3권1호
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• pp.14-20
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• 1999

[ $H_2O/LiBr$ ]계 흡수식 사이클에 압축기를 조합한 흡수압축사이클을 도입하여 증기를 단열압축시켜 그 증기의 응축열을 재생열로 이용하는 사이클에 대해서 시뮬레이션을 통하여 횹수압축사이클의 특성을 밝힌 연구이다. 기존의 흡수사이클에 압축기를 도입함에 따라 고효율 사이클을 실현할 수 있음을 제시하였으며, 흡수$\cdot$압축사이클의 구체적인 가능성을 제시하였다. 재생기에서 발생한 냉매증기를 단열압축시킨 TYPE 2는 단열압축 증기의 응축열만으로는 재생이 어려우므로 외부로부터 별도의 열량을 투입해야 하며 투입하는 외부열량에 폐열이나 2차 에너지를 이용할 수 있다면 높은 COP를 얻을 수 있어 실현가능성이 높다.

• 한국표면공학회지
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• 제57권2호
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• pp.92-97
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• 2024

The LiBr aqueous solution, which is the absorption liquid of absorption refrigerator, must be replaced periodically because the concentration of impurities such as Cu²⁺, Fe²⁺, Ca²⁺, etc., increases due to corrosion of the tubes as the period of use increases, and the refrigeration efficiency decreases significantly. In order to reuse the waste absorption liquid, flocculation-precipitation method is mainly applied to precipitate the impurities, which requires hundreds of times the concentration of impurities and generates additional waste. In this study, a process for removing Cu ion impurities from cyclone electrolyzer by electrolytic reduction is presented in a small-scale facility without additional waste. It was confirmed that Cu ion impurities can be removed down to 1 ppm by electrolytic reduction process, and to further improve the removal rate, the mass transfer rate was increased by using a cyclone electrolyzer. The removal rate of Cu ions increased with the increase of flow rate and current density, and it was confirmed that Cu was removed at a rate of 1.48 ppm/h under the condition of 330 mL/sec and 2.5 mA/cm².

• 한국잠사곤충학회지
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• 제37권1호
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• pp.33-38
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• 1995

견 fibroin을 8M LiBr 수용액에 침지하여 연신처리에 의한 견의 구조와 물성변화를 시험해 보았다. 1. 연사의 역학적 성질은 8M LiBr 수용액의 처리온도 상승에 따라서 강도와 신도는 증가하나 Young's율은 감소하는 경향이었다. 8$0^{\circ}C$ 처리의 X선회절에 있어서는 염축에 의해 분자배향은 흐트러지나 SilkII형의 결정구조는 변하지 않았다. 2. 8M LiBr수용액을 사용하여 8$0^{\circ}C$에서 1시간 처리하면 160%정도 연신이 가능하며 고연신시의 역학적 성질에 있어서는 강도와 Young's율은 증가하고 신도는 감소하였으나 X선회절에서는 연신율의 증가와 함께 결정이 고배향화되는 경향이었다. 3. DSC의 시차열 Thermogram에서 무처리의 연사와 8M LiBr 수용액에 처리되어진 미연신의 연사사이에는 열분해거동이 다른 것이 관찰되었으며 열분해 최대 Peak점의 온도는 연신율의 증가에 따라 조금씩 고온쪽으로 이동함으로써 X선회절사진의 결과와 일치하고 있다.

• Journal of Advanced Marine Engineering and Technology
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• 제30권4호
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• pp.463-473
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• 2006

The effect of tube diameter on heat and mass transfer characteristics of absorber in absorption chiller/heater using LiBr solution as a working fluid has been investigated by both of numerical and experimental study to develop a high performance and compact absorber. The diameter of the heat exchanger tube inside absorber was changed from 15.88mm to 12.70mm and 9.52mm. In numerical study a model of vapor pressure drop inside tube absorber based on a commercial 20RT absorption chiller/heater was performed. The effect of tube diameter, longitudinal pitch, vapor Reynolds number, longitudinal pitch to diameter ratio on vapor pressure drop across the heat exchanger tube banks inside absorber have been investigated and found that vapor pressure drop decreases as tube diameter increases, longitudinal pitch increases, vapor Reynolds number decreases and longitudinal pitch to diameter ratio increases. In experimental study, a system includes a tube absorber, a generator, solution distribution system and cooling water system was set up. The experimental results shown that the overall heat transfer coefficient, mass transfer coefficient. Nusselt number and Sherwood number increase as solution flow rate increases. In both of study cases, the heat and mass transfer performance increases as tube diameter decreases. Among three different tube diameters the smallest tube diameter 9.52mm has highest heat and mass transfer performance.

• 한국의류산업학회지
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• 제4권2호
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• pp.198-202
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• 2002

Degummed silk from Bombyx mori was dissolved in 9.3M lithium bromide solution. The regenerated silk fibroin films were completely ${\alpha}$-randomcoil type as shown by x-ray diffraction and infrared spectroscopy. The structural changes in silk fibroin induced by immersion into methanol and dilute hydrochloric acid and its photo-yellowing effect was studied. The changes of crystallinity were measured by infrared spectrometer. Yellowness index caused by ultraviolet irradiation were observed as a function of the structural change on silk fibroin. On treatment with methanol, ${\alpha}$-randomcoil silk film is converted to the ${\beta}$-form structure. After the treatment of hydrochloric acid on ${\beta}$-form structure in silk induced by immersion into methanol, ${\beta}$-form in silk fibroin is partially decreased. Crystallization owing to ${\beta}$-form transition reduced the initial yellowness index by ultraviolet irradiation. A little ${\beta}$-form structure in silk fibroin increased the initial yellowness in comparison with more ${\beta}$-form structure.

• 한국태양에너지학회 논문집
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• 제27권4호
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• pp.19-26
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• 2007

This paper concerns the study of absorption refrigeration and heat pump cycle to use sewage. Simulation analysis on the double-effect absorption refrigeration cycle with parallel and two-stage heat pump cycle has been performed. The working fluid is Lithium Bromide and water solution. The absorption refrigeration cycle use sewage as a cooling water for the absorber and condenser, and absorption refrigeration cycle does that as a chilled water for the evaporator of the first stage cycle. And the two-stage cycle consists of coupling double-effect with parallel and single effect cycle so that the first stage absorber and condenser produces heating water to evaporate refrigerant in the evaporator of the second stage. The effects of operating variables such as a absorber temperature on the coefficient of performance have been studied for absorption refrigeration and heat pump cycle.