• 공업화학
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• 제7권5호
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• pp.1015-1019
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• 1996

알루미나에 LiBr와 $CaBr_2$를 각각 흡착시켜 용매가 없는 상태에서 여러 가지 염화 알킬과 반응시켜 좋은 수득률로 해당하는 브롬화 생성물을 얻을 수 있었다. 이러한 높은 반응성은 알루미나에 흡착되어 있는 극소량의 물과 브롬화 금속간의 상호작용이 알루미나 상에서 일어날 수 있기 때문이라는 것을 Differential scanning calorimetry (DSC) 열분석 실험과 문헌을 통하여 고찰하였다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2001년도 춘계학술대회 논문집
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• pp.95-99
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• 2001

As a way to use energy effectively, the present study is aimed at investigating the performance characteristics of a Single Effect LiBr/Water Absorption Refrigerator using a low temperature driving heat-source. It was carried out by changing the driving heat-source temperature, the cold water outlet temperature(the refrigeration load), the cooling water inlet temperature, and the weak solution flow rate and this study compares the performance characteristics of refrigerator against the existence and non-existence of the Recirculation of the Weak solution which is used as a method to improve the performance of refrigerator. In case of Recirculation of the weak solution, more improved the Refrigeration Capacity and COP was obtained, and these effects became more larger in the high temperature of driving heat-source and large quantity of solution.

• 설비공학논문집
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• 제14권12호
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• pp.1078-1083
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• 2002

The objectives of this paper are to measure the concentration of $H_2$O/LiBr solution by measuring the electrical conductivity and to study the effect of the solution temperature and the concentration on the electrical conductivity of the solution. The solution temperature ranges $20^{\circ},\;40^{\circ},\;and\; 60^{\circ}$ for a fixed concentration during the experiment. The valid ranges of the concentration are two regions, low concentration region (1~20% of LiBr) and high concentration region (55~66% of LiBr). The results show that the conductivity of the solution increases linearly with increasing the solution temperature while it increases without creasing the concentration lower than about 35% of LiBr and decreases with increasing the concentration higher than 35%. This paper proposes experimental correlations for the concentration as functions of the solution temperature and the concentration with error band of $\pm7$% for the low concentration region and $\pm1$% for the high concentration region, respectively. The experimental correlation can be practically used in the on-line measurement without any sampling of solution from the closed system.

• 설비공학논문집
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• 제10권1호
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• pp.79-87
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• 1998

Basic design of a 50USRT(175㎾) triple effect absorption chiller driven by hot gas has been carried out for both parallel and series flow cycles. Parallel flow cycle showed higher COP, however, the temperature in the generator was also higher than that in series flow cycle. Dynamic operation behavior of a parallel flow system at off-design conditions, such as the change in heat transfer medium temperature or the construction change of the system components, has been investigated in detail. It was found that the cooling capacity was seriously decreased by reducing hot gas flow rate and UA-value in the high temperature generator. However, the system COP was improved, because thermal load in the system components was reduced. The COP and the cooling capacity was found to be improved as cooling water temperature decreased or chilled water temperature increased. The optimum ratio of solution distribution could be suggested by considering the COP, the cooling capacity and the highest temperature in the system, which is critical for corrosion.

• 설비공학논문집
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• 제10권4호
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• pp.456-465
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• 1998

Effect of a non-absorbable gas on the absorption process in a vertical tube absorber was investigated numerically. The water vapor mined with air as the non-absorbable gas is absorbed into LiBr/water solution film. The flow is assumed to be laminar and fully developed in both liquid and gas phases. The diffusion and energy equations were solved in both phases to give the temperature and concentrations, from which heat and mass fluxes were determined. It was shown that the local absorption rate decreases as the mass fraction of air in water vapor increases. The vapor pressure of water at the liquid-vapor interface reduces significantly since the non-absorbable gas is accumulated near the interface. The effect of non-absorbable gases on absorption rate becomes larger as the mass flow rate of the vapor decreases. For small amount of non-absorbable gases the total absorption rate of water vapor increases as the mass flow rate of the vapor decreases. Total absorption rate increases as the mass flow rate of the vapor increases for large concentration of non-absorbables at the inlet of an absorber.

• 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.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.534-539
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• 2007

The objectives of the present work is to investigate the influence of the solution cooled absorber(SCA), refrigerant drain heat exchanger(RSX), exhaust gas/solution heat exchanger(ESX) and high efficiency solution heat exchanger on COP for a double-effect series-flow absorption chiller. A simulation program has been prepared for the cycle analysis of absorption chillers. As a result, Solution heat exchangers(LSX, HSX) are a most effective element for the COP than the others. In spite of the poor contribution to COP, SCA make a rule to reduce the crystallization phenomena of LiBr solution at solution heat exchanger. And the optimum solution split ratio are varied with the relative size of RSX and LSX.

• 설비공학논문집
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• 제20권10호
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• pp.662-668
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• 2008

The objectives of the present work are to investigate the influence of the solution cooled absorber(SCA), refrigerant drain heat exchanger(RSX), exhaust gas/solution heat exchanger(ESX) and high efficiency solution heat exchanger on COP for a double-effect series-flow absorption chiller. A simulation program has been prepared for the cycle analysis of absorption chillers. As a result, solution heat exchangers(LSX, HSX) are the most effective element for the COP than the others. In spite of the poor contribution to COP, SCA plays an important role to reduce the crystallization phenomena of LiBr solution at solution heat exchanger. And the optimum solution split ratio varies with the relative size of RSX and LSX.

• 폴리머
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• 제33권5호
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• pp.509-513
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• 2009

키토산/피브로인 블렌드의 구조와 물성에 미치는 브롬화 리튬의 효과를 고찰하기 위하여, 브롬화 리튬을 함유한 용액으로 성형한 키토산/피브로인 블렌드 필름과 성형 시 브롬화 리튬을 제거한 블렌드 필름의 구조적 특성을 조사하였다. 키토산/피브로인 블렌드는 용해된 브롬/리튬이온과 더불어 복합체를 형성하였고, 0.6 mol/L의 LiBr 농도에서 X-선 회절에 의한 복합체의 결정성을 보였으며, 이온 농도가 증가할수록 결정성은 감소되었다. 복합체 용액으로부터 고화 시중화 및 삼투작용으로 브롬화 리튬을 제거한 블렌드 필름의 결정은 키토산의 수화형 결정상을 형성하였으며, 브롬화 리튬을 처리하지 않은 것에 비하여 결정성이 크게 증가하였다. 복합체에 의한 블렌드 필름은 자중의 수십 배의 물을 흡수하여 수화겔을 형성하였다.

• 설비공학논문집
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• 제29권1호
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• pp.7-14
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• 2017

This study carried out a numerical analysis of the effects of hot waste water supply on the performance of a Type II absorption heat pump. There are two types of hot waste water supply, regular series flow and reverse series flow. Also it investigated the interaction between each type of flow and heat exchange solutions. As the effectiveness of heat exchange solutions increase, the steam generation and (COP) increase as well. If the effectiveness of a heat exchange solution is lower than 0.566, the steam generation rate of the reverse flow is lower than that of the regular series flow. A high effectiveness of heat exchange solution is therefore required to make a larger amount of steam in reverse series flow than with ordinary series flow. The COP difference between the two types of flow decreases with the increasing effectiveness of the heat exchange solution. Thus, a reverse flow type absorption heat pump can match the high steam generation rate and COP of the ordinary flow type when a highly effective heat exchange solution is applied.