• 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.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.272-278
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• 2009

The characteristics of hybrid type absorption chiller are studied numerically to use a waste hot water effectively. In the case of the full load, the concentration and temperature of LiBr solution are increase about $11^{\circ}C$, 1.3% respectively at the single effect generator by hot water. As a result, the heat of the high temperature generator are decrease, so the energy can be saved. As the partial load decreased the consumption ratio of fuels are decreased and the reduction ratio of fuels are increased. The variation of COP with the inlet temperature of hot water is higher than that of the flow rate of hot water. The effect of mean temperature difference with solution and hot water of the generator are higher that of flow rate of hot water, it can effect on COP which is sensitive to heat of generator.

• Polymer(Korea)
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• v.33 no.5
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• pp.509-513
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• 2009

For examining an effect of lithium bromide on structure and property of chitosan/fibroin blend, we investigated the structural characteristic of chitosan/fibroin blend films using solution with lithium bromide which was removed during a casting. The chitosan/fibroin blend formed a complex with the dissolved bromine/lithium ions. The crystalline phase of the complex was found in the blend film at LiBr concentration of 0.6 mol/L. The degree of crystallization was decreased with increasing the concentration of LiBr. The hydrated crystalline phase of chitosan was formed in the blend film that lithium bromide was removed in the process of casting by neutralization and osmotic action. The crystallinity of this film was increased largely as compared with that of the film without lithium bromide. The complexed blend film formed hydrogel absorbing plenty of water.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.7
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• pp.373-384
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• 2017

The objective of this study was to determine the effect of refrigerant heat exchanger on the performance of type II absorption heat pump performance using numerical analysis. Two heat exchange installation methods were used: solution to refrigerant and waste hot water to refrigerant. These methods were compared to the standard model of hot water flow without using refrigerant heat exchanger. When waste hot waters were bypassed to refrigerant heat exchanger, COP was not affected. However, steam mass generation rates were increased compared to those of the standard model. When solutions were bypassed to the refrigerant heat exchanger, results were different depending on the place where the solution rejoined. COP and steam mass generation rates were lower compared to those when waste heat water was passed to refrigerant heat exchanger. Thus, it is possible to obtain higher steam mass generation rates by using waste water and installing refrigerant heat exchanger.

• Journal of the Korean Chemical Society
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• v.37 no.3
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• pp.309-316
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• 1993

The limiting equivalent ionic conductances of Li$^+$, Na$^+$, K$^+$, Cl$^-$, and Br$^-$ ions were obtained with TATB[Tetraphenyl Arsonium Tetraphenyl Borate] method from limiting equivalent conductances of LiCl, NaCl, KCl and KBr measured in water-methanol systems by conductometric method. With those values and viscosity of water-methanol systems, the Stokes radii of corresponding ions have been extracted. The latter values corrected by calibration method of Nightingale and supplemented by the crystallographic radii were utilized to calculate the volume of solvation-shell that surrounds ions. The reasonable solvation numbers (h$_{H_2O}$ ＋ h$_0$) were estimated by comparing the values obtained by the various suggested methods. The selective properties of ion solvation were also discussed.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2434-2439
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• 2008

This paper was studied on the cavitation instability of a Solution Pump Inducer in an absorption chiller-heater. Inlet pressure of LiBr and rotational speed at nominal mode are 2,800 Pa and 3,500 rpm respectively. Due to the marginal operation of available NPSH, the cavitation performance of the inducer is critical for the stable operation without the deterioration of head performance. In the study, cavitation performance and its mode of instability was investigated experimentally. Water was used as the working fluid and the test inducer was scaled up as 1.75 times for detail measurements and flow visualization. Inlet pressure was controlled by a vacuum pump. This research focused on types of cavitation instability and phenomena to investigate the possibility of harmful damage due to cavitation instability. Casing wall pressure and instantaneous inlet pressure was measured to observe the unsteady flow characteristics. Through the visualization and spectrum analysis of pressure, the occurrence region and intensity of asymmetric cavitation and cavitation surge are analyzed in the test inducer.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.791-795
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• 1992

The limiting equivalent conductances of LiCl, NaCl, KCl and KBr have been obtained in water using conductometric method from 1 to 2000 bars at $25^{\circ}C$. From the limiting equivalent ionic conductances (obtained using TATB[Tetraphenyl Arsonium Tetraphenyl Borate]method) of $Li^+$, $Na^+$, $K^+$, $Cl^-$, and $Br^-$ ions and viscosity of water at given pressure, their Stokes radii have been calculated. From the corrected radii caliberated by Nightingale method and the crystallographic radii at a given pressure, the volume of hydration-shell surrounding ion was calculated and hydration numbers of $Li^+$, $Na^+$, $K^+$, $Cl^-$, and $Br^-$ ions were obtained. From the experimental results, it was found that the hydration number of $Li^+$, $Na^+$, $K^+$, $Cl^-$, and $Br^-$ ions slightly decreased with increasing pressure. This trend may be explained by Horne's suggestion[Advances in High Pressure Research]. Comparing results of this study with those of Nakahara's, the hydration numbers of $K^+$ and $Cl^-$ ions were almost twice as large as those of Nakahara's[Rev. Phys. Chem. Japan, 42, 12 (1972)]. By comparing the present results with those of Kollman's [J. Am. Chem. Soc., 113, 2481 (1991)], the hydration number obtained by applying TATB method and Nightingale method may be inferred to be reasonable.

• Solar Energy
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• v.9 no.3
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• pp.73-80
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• 1989

This paper presents as assessment based on steady-state thermodynamic analysis and computer modeling of a double effect generation absorption heating cycle for solar air-conditioning to find operating temperature ranges. The influences of component temperatures on the heating coefficients of performance and mass flow ratio have been investigated to obtain optimum operating conditions for the proposed air conditioning system. And the single and double effect absorption cycles are compared with each other over the same range of temperatures.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1994.05a
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• pp.103-108
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• 1994

리튬브로마이드 수용액이 수직관내면을 따라 액막의 형태로 흘러 내릴때 수증기와의 흡수과정에 대하여 열 및 물질전달 특성을 실험하였다. 실험에서 열 및 물질전달계수는 막레이놀즈수를 30에서 200까지 변화시키면서 실시하였다. 일정한 냉방능력에서 시스템 압력을 변화시켰을 때의 열 및 물질전달계수를 측정하였다. 액막의 열전달계수는 레이놀즈수가 증가함에 따라 감소하였다. 최대 질량유량에서 최적의 막레이놀즈수가 존재하였다.

• Journal of Radiation Protection and Research
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• v.15 no.2
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• pp.57-65
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• 1990

Newly developed LiF(Mg, Cu, Na, Si) thermoluminescence phosphors sealed in a plastic capsules (32mm dia., 0.9mm wall thickness) were used for in-phantom dosimetry of $^{60}Co$ $\gamma$-irradiation. The absorbed doses in water were determined by applying the general cavity theory to the absorbed dose in TLD cavity, which was computed from exposure. The absorbed doses at various sites in the water-phantom were measured by LiF(Mg, Cu, Na, Si) TLD and compared with doses obtained by the ionization method. Both results were consistent within the experimental fluctuation$({\pm}3%)$ Central axis percentage depth doses and phantom-air ratios measured by LiF(Mg. Cu, Na, Si) TLD showed good agreement with the published values[Br. J. Radiology, Suppl. 17(1983)].