• Solar Energy
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• v.9 no.3
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• pp.37-43
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• 1989

This paper dealt with thermal storage efficiency due to difference ($T_{\infty}-Ti$) between the mean temperature of water in the storage tank [$0.5m{\times}0.5m{\times}1.0m$] and the temperature of water flowing into the tank, flow rate of water flowing into the tank and shape of porous manifold which water flow into the tank through. As results of experiments; (1) When the flow rate was constant and the diameter of porous section decreased by 8mm, 6mm, and 4mm, the thermal storage efficiency increased. (2) When the diameter of porous section was constant and the difference ($T_{\infty}-Ti$) between the mean temperature of water in the storage tank and the temperature of water flowing into the tank increased by -30, -20, -10, 5, 10, 15 ($^{\circ}C$), the thermal storage efficiency increased. (3) When the($T_{\infty}-Ti$) was constant and the flow rate decreased by 0.8, 0.4, 0.25(LPM), the thermal storage efficiency increased. (4) When the shape of porous section was rigid, the thermal storage efficiency was the most effective, and with establishing flexible porous section or mesh, the effective thermal storage efficiency was obtained.

• Journal of Ocean Engineering and Technology
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• v.4 no.2
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• pp.85-93
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• 1990

A numerical study on the cylindrical packed bed sensible heat storage unit was accomplished by finite difference method. Relation between the heat storage rate and the mechanical pumping energy and the characteristics of the heat storage were investigated for various in let velocities and porosities. In this study, the numerical results are as follows: 1) The temperature distributions of solid and fluid rapidly reached the steady state as the heat capacity ratio was increased. 2) The efficiency of the heat storage was increased as the heat capacity ratio was decreased. For constant heat capacity ratio, however, the efficiency of the heat storage was increased at lower porosity. 3) It is very profitable to design the heat storage system such that the porosity is larger for the large flow rate and samller for small flow rate.

• Journal of Ocean Engineering and Technology
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• v.4 no.2
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• pp.235-235
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• 1990

A numerical study on the cylindrical packed bed sensible heat storage unit was accomplished by finite difference method. Relation between the heat storage rate and the mechanical pumping energy and the characteristics of the heat storage were investigated for various in let velocities and porosities. In this study, the numerical results are as follows: 1) The temperature distributions of solid and fluid rapidly reached the steady state as the heat capacity ratio was increased. 2) The efficiency of the heat storage was increased as the heat capacity ratio was decreased. For constant heat capacity ratio, however, the efficiency of the heat storage was increased at lower porosity. 3) It is very profitable to design the heat storage system such that the porosity is larger for the large flow rate and samller for small flow rate.

• Biomedical Science Letters
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• v.23 no.2
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• pp.111-117
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• 2017

Leukocytes in blood components are involved in diverse adverse transfusion reactions such as febrile non-hemolytic transfusion reactions. Therefore, leukocyte reduction is required to reduce these adverse reactions. The objective of this study was to compare the efficiency of pre-storage filtration and post-storage filtration. Filtration time, residual leukocyte count, RBC recovery, and hemolysis were assessed after pre-storage or post-storage filtration. Compared to pre-storage filtration, filtration time was prolonged and hemolysis was dramatically increased when post-storage filtration was performed. Residual leukocytes count and RBC recovery after post-storage filtration were similar with those obtained after pre-storage filtration. These results suggest that pre-storage filtration has better efficiency than post-storage filtration. These are thought to contribute to the production of better quality of leukoreduction blood components.

• Progress in Superconductivity and Cryogenics
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• v.22 no.4
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• pp.45-50
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• 2020

In this research, the variation of round-trip efficiency in a liquid air energy storage system (LAES) is calculated and an optimal configuration is found. The multiple stages of cold energy storage are simulated with several materials that process latent heat at different temperature ranges. The effectiveness in the charging and discharging processes of LAES is newly defined, and its relationship with the round-trip efficiency is examined. According to defined correlation, the effectiveness of the discharging process significantly affects the overall system performance. The round-trip efficiency is calculated for the combined cold energy storage materials of aqueous dimethyl sulfoxide (DMSO) solution, ethanol, and pentane theoretically. The performance of LAES varies depending on the freezing point of the cold storage materials. In particular, when the LAES uses several cold storage materials, those materials whose freezing points are close to room temperature and liquid air temperature should be included in the cold storage materials. In this paper, it is assumed that only latent heat is used for cold energy storage, but for more realistic analyzes, the additional consideration of the transient thermal situation to utilize sensible heat is required. In the case of such a dynamic system, since there is certainly more increased heat capacity of the entire storage system, the volume of the cold energy storage system will be greatly reduced.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.296-301
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• 2009

The ice storage system uses water for low temperature latent heat storage. However, a refrigerator capacity is increased and COP is decreased due to supercooling of water in the course of phase change from solid to liquid. This study investigates the cooling characteristics of the TMA-water clathrate compound including TMA (Tri-methyl-amine, $(CH_3)_3N)$ of $20{\sim}25wt%$ as a low temperature latent heat storage material. The results showed that the phase change temperature and the specific heat is increased and the supercooling degree is decreased as the weight concentration of TMA increased. Especially, the clathrate compound containing TMA 25wt% has the average phase change temperature of $5.8^{\circ}C$, the supercooling degree of $8.0^{\circ}C$ and the specific heat of 3.499 kJ/kgK in the cooling process. This can lead to reduction of operation time of refrigerator in low temperature latent heat storage system and efficiency improvement of refrigerator COP and overall system. Therefore, energy saving and improvement of utilization efficiency are expected.

• International Journal of Automotive Technology
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• v.8 no.6
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• pp.667-674
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• 2007

Various types of NOx storage catalysts for NGV's were designed, manufactured, and tested in this work on a model gas test bench. As in most of other studies on NOx storage catalyst, alkaline earth metal barium(Ba) was used as the NOx adsorbing substance. The barium-based experimental catalysts were designed to contain different amounts of Ba and precious metals at various ratios. Reaction tests were performed to investigate the NOx storage capacity and the NOx conversion efficiency of the experimental catalysts. From the results, it was found that when Ba loading of a catalyst was increased, the quantity of NOx stored in the catalyst increased in the high temperature range over 350. With more Ba deposition, the NOx conversion efficiency as well as its peak value increased in the high temperature range, but decreased in the low temperature range. The best of de-NOx catalyst tested in this study was catalyst B, which was loaded with 42.8 g/L of Ba in addition to Pt, Pd and Rh in the ratio of 7:7:1. In the low temperature range under $450^{\circ}C$, the NOx conversion efficiencies of the catalysts were lower when $CH_4$, instead of either $C_3H_6$ or $C_3H_8$, was used as the reductant.

• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.1
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• pp.32-36
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• 2009

The ice storage system uses water for low temperature latent heat storage. However, a refrigerator capacity is increased and COP is decreased due to supercooling of water in the course of phase change from solid to liquid. This study investigates the cooling characteristics of the TMA-water clathrate compound including TMA (Tri-methyl-amine, $(CH_3)_3N$) of $20{\sim}25wt%$ as a low temperature latent heat storage material. The results showed that the phase change temperature and the specific heat is increased and the supercooling degree is decreased as the weight concentration of TMA increased. Especially, the clathrate compound containing TMA 25 wt% has the average phase change tempera ture of $5.8^{\circ}C$, the supercooling degree of $8.0^{\circ}C$ and the specific heat of 3.499 kJ/kgK in the cooling process. This can lead to reduction of operation time of refrigerator in low temperature latent heat storage system and efficiency improvement of refrigerator COP and overall system. Therefore, energy saving and improvement of utilization efficiency are expected.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.13-16
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• 1988

As the automic power plant is increased, load leveling energy storage system becomes more important. Pumped hydroelectric storage, used in the present, has too storage efficiency and difficulty in selecting site. But SMES(Superconducting Magnet Energy Storage) has high storage efficiency (90%), fast time response characteristics and ease of location. The general object of SMES with electric power system is the minimization overall production cost. This paper presents a method for the economic operation of SMES by Dynamic Programming.

• Solar Energy
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• v.18 no.3
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• pp.71-80
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• 1998

In thermal energy storage system, energy collected from many types of heat source is stored in a storage tank and then supply to load for demand. Lately, practical use of thermal energy storage system and attention to essential use of energy have been increased. From this point of view, especially, a study about the energy extraction process from a storage tank is necessary. So in this study, useful rate of hot water and hot water extraction efficiency was analysed respect to dynamic and geometric parameters dominating the hot water extraction process.