• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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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.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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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.

• Journal of the Korean Solar Energy Society
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• v.22 no.4
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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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• v.6
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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.

• Journal of the Korean Institute of Gas
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• v.3 no.1
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• pp.14-20
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• 1999

This study describes the results of Coefficient of Performance(COP) analysis by cycle simulation for two types of absorption-compression hybrid cycle using the Water/Lithium Bromide solution pair. These types are basic hybrid systems introducing a mechanical compression process into the refrigerant vapor phase of the single effect absorption cycle. In absorption-compression hybrid cycles, coefficient of performance is improved compared with absorption cycle. Hybrid cycle Type 2 is considered as a key technology to support energy utilization system, given its capability of utilizing waste heat to drive system with a high level of efficiency.

• Journal of the Korean institute of surface engineering
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• v.57 no.2
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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.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.33-38
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• 1995

The mechanical properties and structure of degummed silk fiber stretched after being treated with 8M LiBr aqueous solution were investigated. The mechanical properties of degummed silk fiber were depended upon the treatment temperature of 8M LiBr aqueous solution. That is, the strength and elongation had a tendancy to increase with the temperature, whereas the Young's modulus tended to decrease. The X-ray diffraction pattern showed that the crystalline orientation was disordered by 8$0^{\circ}C$ treatment neverthless destruction of the crystallites did not occur. rho silk fiber could be successfully stretched up 160% under the condition of 8M LiBr aqueous solution at 80 * after immersed for 1hr. For the highly stretched sample(160%), the tensile strength and Young's modulus were significantly improved in spite of lower elongation at break. According to the examination of X-ray diffraction pattern and SEM, the orientation tends to be occured more and more with stretching ratio. From the DSC thermograms, it shows that the thermal decomposition behavior was different between untreated and treated specimen with 8M LiBr aqueous solution. The maximun endothermic peak of thermal decomposition tends to increase to high temperature with the increase of stretching ratio.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.4
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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.

• Fashion & Textile Research Journal
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• v.4 no.2
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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.

• Journal of the Korean Solar Energy Society
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• v.27 no.4
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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.