• Title/Summary/Keyword: LiBr

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Effect of LiBr solution flow rates in commercial absorption chiller (상용 흡수식 냉동기에서 LiBr 수용액 유량변화에 따른 영향)

  • Choi, S.H.;Chung, B.C.;Nam, L.W.;Jurng, J.;Chin, S.
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.292-297
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    • 2001
  • This paper discusses the effect of varying LiBr solution circuits flow rates for a direct fired double effect commercial absorption chiller in the parallel flow configuration. The effects of solution flow rates have been investigated for generator, condenser, solution heat exchanger, absorber and evaporator. According to the result of this work, it was found that sensible heat rate of generator increases and refrigerant vapor generated in that decreases when inlet solution flow rate of that increases. As solution flow rate of absorber increases, the degree of superheat increases because of decreasing solution heat exchanger efficiency. The flashing vapor at the top of absorber increases in proportion to the degree of superheat whileas decreases cooling capacity inversely.

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Coupled Heat and Mass Transfer during the Absorption of Water Vapor into LiBr-H2O Liquid Solution Flowing down the Outside of the Horizontal Cylinder (수평원관상의 LiBr-수용액에 수증기가 흡수될때의 열 및 물질전달)

  • Lee, K.S.;Seo, S.C.;Kim, Y.I.;Park, D.K.
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.17 no.2
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    • pp.140-149
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    • 1988
  • The problem of heat and mass transfer accompanying the absorption of water vapor into LiBr-$H_2O$ liquid solution flowing over the outside of the horizontal cylinder was theoretically studied to understand the absorption process occuring in the absorber of the absorption heat pump. Numerical results are presented for various quantities of interest relating to temperature, concentration, heat flux and mass flux. Also, the effects of mass flowrate, initial average velocity, and the radius of the cylinder were investigated.

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Coupled Heat and Mass Transfer in Absorption of Water Vapor into LiBr-$H_2O$ Solution Flowing over a Finned Inclined Surface (좁은 휜이 달린 경사면을 흐르는 리튬브로마이드 수용액 흡수기에서의 열 및 물질전달)

  • 조은준;서태범
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.9
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    • pp.860-867
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    • 2001
  • Absorption of water vapor into LiBr-$H_2O$ O solution flowing over a finned inclined surface is numerically investigated. The momentum, energy, and diffusion equation are numerically solved using a finite difference method. The four different shapes of the wall surfaces are considered to find the best surface for absorption assuming that the wall temperature and the surface tension are constant. The effects of the fin interval and Reynolds number are investigated. Based on the numerical results, it is known that the parabolic surface shows better absorption performance than the other surfaces, and that water vapor absorption increases gradually with decreasing the fin interval.

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Experimental investigation of enhanced heat and mass transfer toy LiBr/$H_2O$ absorber (LiBr/$H_2O$계 흉수기의 흡수촉진에 관한 실험적 연구)

  • 설원실;권오경;윤정인
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.5
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    • pp.581-588
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    • 1998
  • An experimental study of the absorption process of water vapor into Lithium Bromide solution was performed. For the purpose of development of high performance absorption chiller-heater utilizing Lithium Bromide solution as working fluid, the absorber is the most effective to improve the performance of an absorber because it requires the largest heat transfer area in an absorption chiller-heater system. This paper introduces bare tube and floral tube for the absorber of absorption chiller-heaters. floral tube has higher heat and mass transfer performance than bare tube conventionally used in absorbers and the it is expected to perform high heat and mass transfer. This paper will provide important information on the selection of absorber tubes in commercial absorption chiller -heaters.

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Parametric Study on the $LiBr-H_{2}O$ Absorption Process on Horizontal Tubes Using Wavier-Stokes Equations (Navier-Stokes 방정식을 사용한 수평원관상의 $LiBr-H_{2}O$ 흡수특성에 대한 연구)

  • Min J. K.;Choi D. H.
    • 한국전산유체공학회:학술대회논문집
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    • 1999.05a
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    • pp.213-218
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    • 1999
  • The $LiBr-H_{2}O$ absorption process on a horizontal tube has been analyzed using the numerical method which incorporates the fully elliptic Navier-Stokes equations for the momentum equations, the energy and mass-diffusion equations. On a staggered grid, the SIMPLER algorithm with the QUICK scheme is used to solve these equations along with the MAC method for the free surface tracking. With the assumption that the absorbent is linear, calculations have been made for various inlet temperature and flow-rate conditions. The detailed results of the parametric study, such as the temperature, concentration, absorption mass flux and wall heat flux distributions are presented. The self-sustained feature of the absorption process is clearly elaborated. The analyses have also been carried out for multiple tube arrangement and the results show that the absorption rate converges after a few tube rows.

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Simulation of the Second Kind LiBr - H2O Absorption Heat Pump (2종 LiBr - H2O 흡수식 열펌프의 시뮬레이션)

  • Huh, J.Y.;Choi, Y.D.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.1 no.2
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    • pp.146-161
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    • 1989
  • The second kind LiBr-$H_2O$ absorption heat pump system was simulated and the performances of it were predicted. The elements of heat pump system, evaporator, absorber and generator were analysed by solving the energy balance equations and concentration equations which describe the reactions between working fluids. The results show that the temperature gain of absorber is affected considerably by the operating conditions of heat pump system, on the other hand, COP is little affected by them.

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Coupled Heat and Mass Transfer in Absorption of Water Vapor into LiBr-$H_2O$ Solution Flowing on Finned Inclined Surfaces

  • Seo, Taebeom;Cho, Eunjun
    • Journal of Mechanical Science and Technology
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    • v.18 no.7
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    • pp.1140-1149
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    • 2004
  • The absorption characteristics of water vapor into a LiBr-H$_2$O solution flowing down on finned inclined surfaces are numerically investigated in order to study the absorbing performances of different surface shapes of finned tubes as an absorber element. A three-dimensional numerical model is developed. The momentum, energy, and diffusion equations are solved simultaneously using a finite difference method. In order to obtain the temperature and concentration distributions, the Runge-Kutta and the Successive over relaxation methods are used. The flat, circular, elliptic, and parabolic shapes of the tube surfaces are considered in order to find the optimal surface shapes for absorption. In addition, the effects of the fin intervals and Reynolds numbers are studied. The results show that the absorption mainly happens near the fin tip due to the temperature and concentration gradient, and the absorbing performance of the parabolic surface is better than those of the other surfaces.

Performance analysis of a cooling system with refrigerant in a marine absorption refrigerator (선박용 흡수식 냉동기의 냉매적용 냉각 시스템 성능 분석)

  • Yun, Sang-Kook
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.4
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    • pp.282-287
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    • 2016
  • Recently in order to protect the ocean environment and to reduce energy consumption, shipbuilders have been developing highly economized ships. This research analyzed the possibility of adopting the onshore absorption refrigerator to offshore ships having a cooling system with refrigerant by using the waiste heat of the engine jacket cooling water instead of compression refrigerators. The results showed that R236fa could be a suitable medium for absorbing the heat of the absorber and condenser in an absorption refrigerator. The cooling system using R236fa achieved a high COP of 0.798, which is 15% and 5% higher than an air cooling system with a cooling tower and a water cooling system with a heat exchanger, respectively. The cooling system with R236fa achieved high efficiency with a 25% reduction in flow rate of LiBr solution and only 15.7% flow rate of cooling medium as compared to the water cooling system. The heating of sea water by the engine jacket water flowing out from the generator can prevent the crystallization of LiBr solution due to the low temperature of sea water.

Reaction Behavior of Ceramic Mat with Lithium Salt for the Electrolyte Separators of Thermal Batteries (전해질 분리판용 세라믹 부직포와 리튬염간의 반응성)

  • Cho, Kwang-Youn;Riu, Doh-Hyung;Shin, Dong-Geun;Lim, Kyoung-Hoon;Jin, Eun-Ju;Kim, Hyoun-Ee;Ha, Sang-Hyeon;Choi, Jong-Hwa
    • Journal of the Korean Ceramic Society
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    • v.46 no.6
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    • pp.587-591
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    • 2009
  • Lithium salt have been used mainly as electrolyte of thermal battery for electricity storage. Recently, The 3phase lithium salt(LiCl-LiF-LiBr) is tried to use as electrolyte of thermal battery for high electric power. It is reported that LiCl-LiF-LiBr salt have high ion mobility due to its high lithium ion concentration. Solid lithium salt is melt to liquid state at above $500{^{\circ}C}$. The lithium ion is easily reacted with support materials. Because the melted lithium ion has small ion size and high ion mobility. For the increasing mechanical strength of electrolyte pellet, the research was started to apply ceramic filter to support of electrolyte. In this study, authors used SiOC web and glass fiber filter as ceramic mat for support of electrolyte and impregnated LiCl-LiF-LiBr salt into ceramic mat at above $500{^{\circ}C}$. The fabricated electrolyte using ceramic mat was washed with distilled water for removing lithium salt on ceramic mat. The washed ceramic mat was observed for lithium ion reaction behavior with XRD, SEM-EDS and so on.

Electrochemical Properties on High Temperature Operating Battery by Electrolyte and Salts in Electrodes (고온 작동형 전지의 전해질 및 전극내 첨가염 변화에 따른 전기화학적 특성 연구)

  • Choi, Yu-Song;Ha, Sang-Hyun;Cho, Sung-Baek
    • Journal of the Korea Institute of Military Science and Technology
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    • v.14 no.4
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    • pp.740-746
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    • 2011
  • Thermally activated batteries have good stability, reliability and long shelf life. Due to these characteristics and operational mechanism, thermal batteries are usually applied to military power sources. Especially, Li/$FeS_2$ thermal batteries, which are used mostly in these days, use LiCl-KCl and LiBr-LiCl-LiF as electrolytes. The electrochemistry of thermal batteries have been researched for long time, however, electrochemical study using impedance spectroscopy was not published so much. Through this research, microscopic electrochemical research was investigated with electrochemical impedance spectroscopy(E.I.S). Electrolyte effects on Li/$FeS_2$ thermal battery was researched changing electrolytes, LiCl-KCl and LiBr-LiCl-LiF. Additionally, the salts, which are added to electrolytes, effects on thermal battery were researched. It is expected that the impedance spectroscopy analysis is applicable to not only thermal battery electrochemical study effectively, but also, thermal battery developments.