• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.9
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• pp.1241-1248
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• 2002

Performance extension of the absorption refrigerator with LiBr solution is often faced to operate very close to the crystallization limit. Especially in the development of an air-cooled cycle, the crystallization of working solution in the system is a very difficult problem to overcome. This paper describes the cycle of hot water driven absorption system using a new working absorption solution instead of LiBr solution to improve the efficiency. In this study, we found out the characteristics of new working absorption solution through the cycle simulation and compared LiBr solution to evaluate. The effect of cooling water temperature, weak solution flow rate, hot water temperature and hot water flow rate were also examined. The COP is increased 22% higher in the case of LiBr＋Li1＋LiC1＋LiNO$_3$＋$H_2O$, 2% LiBr＋HO(CH$_2$)$_3$OH＋$H_2O$ than that of LiBr solution for the same operation condition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.2
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• pp.272-280
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• 1999

A cycle analysis was achieved to predict the characteristics by comprehensive modeling and simulation of an air-cooled, double-effect absorption system using a new $H_2O/LiBr+HO(CH_2)_3OH$ solution. The simulation results showed that the new working fluid may provide the crystallization limit 8% higher than the conventional $H_2O/LiBr$ solution. With a crystallization margin of 3wt%(weight%), the optimal solution distribution ratio was found in the range of 36 to 40%. Variation of cooling air Inlet temperature has a sensitive effect on the cooling COP and corrosion problem. The simulation of heat exchangers with UA value revealed that the absorber and the evaporator are relatively important for an air-cooled system compared with the condenser and the low temperature generator. The effect of cooling air flow rate, circulation weak solution flow rate and chilled water inlet temperature were also examined. The new working fluid may provide the COP approximately 5% higher than the conventional $H_2O/LiBr$ solution.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.2
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• pp.163-170
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• 1997

Solubility on $(LiBr+CaCl_2)$ in water has been measured systematically and compared with those of pure LiBr. It has been observed that there exists optimum value of $CaCl_2(LiBr+CaCl_2)$ in solubility when total$(LiBr+CaCl_2)$ concentration is higher than 57wt%. As total concentration increases up to 65wt%, it is found that the optimum value also increases monotonically. From the experimental results, a master plot has been constructed, with which optimum ratio of LiBr to $CaCl_2$ can be found in terms of total concentration. Vapor pressure of $H_2O/(LiBr+CaCl_2)$ solution with optimum contents of $CaCl_2$ has been observed to be changed negligibly at relatiely low temperature. However, as temperature increases, it is found that increasement in vapor pressure is significant.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.792-799
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• 1998

Further improvement of existing $H_{2}O/LiBr$ absorption refrigeration machine is absolutely neces-sary to promote the utilization of gas-cooling system Among various methods to improve the per-formance of the absorption refrigeration machine this research has focused on the use of a new working fluid that has better properties than the existing $H_{2}O/LiBr$ working fluid. In the series of the research, $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ system was selected as the most promisable candidate. The absorption refrigeration machine is water-cooled double-effect, $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ sys-tem with series flow type. In this study we found out the characteristic of new working solution through the cycle simulation and compared the result with that of LiBr solution to evaluate. Theoptimum designs and operating conditions were determined based on the operating constraints and the coefficient of performance. Results demonstrate that new working fluid subsrantially increases COP by as much as 10% and has a wider working range with 8% higher crystallization limits compared to the conventional $H_{2}O/LiBr$.

• 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.

• 한국가스학회:학술대회논문집
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• 1998.09a
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• pp.249-254
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• 1998

This paper describes the study of developing air-cooled absorption system which uses a new working solution instead of LiBr solution to improve the performance of system. The absorption chiller-heater considered was an air-cooled, double-effect, $H_2O/LiBr+HO(CH_2)_3$ system of parallel flow type. In this study, we found out the characteristic of new working solution through the cycle simulation and compared the result that of LiBr solution to evaluate. The new working fluid has a wider working range with $8\%$ higher crystallization limit at the saturated refrigerant pressure of 0.8kPa. The optimum designs and operating conditions of air-cooled absorption system were suggested based on this cycle simulation analysis. It was demonstrated that new working fluid substantially improves the performance of the absorption refrigeration machine and is expected to increase the COP by as much as $5\%$.

• Proceedings of the SAREK Conference
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• 2007.11a
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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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.10
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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.

• 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.

• Textile Coloration and Finishing
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• v.6 no.1
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• pp.62-70
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• 1994

Silk fibroin was dissolved in 9.3 M LiBr aqueous solution at 4$0^{\circ}C$ for 1 hour. The dissolved silk fibroin was regenerated by casting the dialyzed solution into the membrane. The freshly prepared silk fibroin membrane was soluble in water and was. mainly consisted of random coil conformation. By the treatments in saturated water vapor at 3$0^{\circ}C$ and in 75% ethanolic aqueous solution (V/V), the insoluble membranes were obtained and the structure and morphology of those were investigated for the structure by means of X-ray diffraction analysis, infrared spectroscopy, thermal analysis. Rheovibron and scanning electron micrograph. Silk II type crystals were obtained by treating amorphous silk fibroin membrane in the random coil conformtion with 75% ethanol solution(V/V). Crystallization to silk II type crystals occured even after a few minutes, and a large number of silk II type crystals were formed after 30 mins. On the other and, the membrane treated in saturated water vapor was composed of the mixtures of silk I and silk II type crystals. A large number of silk I and silk II type crystals were formed after 24 hours. The micro brownian motion in the amorphous regions of silk fibroin membrane started at about 175~185$^{\circ}C$. $\alpha$ dispersion appeared at about 20$0^{\circ}C$ in the amorphous membrane, and at about 22$0^{\circ}C$ in the crystalline membrane. The crystallization of random coil conformation to silkII type crystals occured at about 215$^{\circ}C$. The surface, bottom and cross-section of the membranes were observed by scanning electrom microscope. Fine forms alike spherulites appeared at the surface of crystalline membrane.