• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.10
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• pp.3313-3321
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• 1996

A fundamental study in cooling and solidification process focused on ice storage was performed, including the interesting phenomena of density inversion, supercooling and dendritic ice. A numerical study was performed for natural convection and ice formation in the cooling and freezing processes with supercooling in a space between double cylinders. When water was cooled under the freezing point by a cooling wall in a cavity, solidification was not started at once, but a subcooled region was formed near the wall. Especially, when the cooling rate was low, subcooled region extended to a wide area. However, after a few minutes, supercooling is released by some triggers. Dendritic ice is suddenly formed within a subcooled region, and a dense ice layer begins to be developed from the cooling wall. Due to the difficulties, most previous studies on solidification process with numerical methods had not treated the supercooling phenomena, i.e. the case considering only the growth of dense ice. In this study, natural convection and ice formation considering existence of supercooling and dendritic ice were analyzed numerically with using finite difference method and boundary fixing method. The results of numerical analysis were well compared with the experimental results.

• 월간 기계설비
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• s.21
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• pp.120-128
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• 1992

• Solar Energy
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• v.10 no.2
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• pp.28-37
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• 1990

A study was conducted to investigate the feasibility of using a super-absorbent polymer made from a acrylic acid copolymer for a capsule-type ice storage system. In a simple pyrex-tube test, 25% of distilled water samples tested turned out not be frozen at all at $-12^{\circ}C$ and the average supercooling of the samples frozen was $9.8^{\circ}C$. With the addition of 0.5wt% super-absorbent polymer, however, the supercooling of the distilled water was dramatically reduced and more than 35% of samples tested did not show any supercooling. The heat transfer characteristics of a capsule-type ice storage unit was also investigated with a distilled water as the phase-change material. With the addition of 0.5wt% polymer, the supercooling of water was not observed at all and thus an overall heat transfer was enhanced. Based on these results, it was concluded that a super-absorbent polymer is a potential candidate as the nucleating agent for an ice-storage system.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.3
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• pp.376-381
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• 2006

This study is experimented to observe an influence of experimental conditions on production characteristics of slurry ice by putting ball into test section to disturb ice adhesion. And at this experiment it used ethylene glycol-water solution and the concentration is 20wt%. The experimental apparatus was constructed of ethylene glycol-water solution and slurry ice storage tank. brine tank, pumps for ethylene glycol-water solution and brine circulating, a mass flow-meter data logger for fluid temperature measuring and a vertical circular tube with two copper tubes as test section. The experiments were carried out under various conditions, with mean velocity of fluid at the entry ranging from 0.07 to 0.13m/s and ball diameter is 10mm, 15mm. Also ball filling rate is 33%, 50%.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.49-50
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• 2006

This study experimented to observe an influence of experimental conditions on production characteristics of slurry ice by putting ball into test section to disturb ice adhesion. And at this experiment it used ethylene glycol-water solution and the concentration is 20wt%. The experimental apparatus was constructed of ethylene glycol-water solution and slurry ice storage tank, brine tank. pumps for ethylene glycol-water solution and brine circulating, a mass flow-meter, data logger for fluid temperature measuring and a vertical circular tube with two copper tubes as test section. The experiments were carried out under various conditions, with mean velocity of fluid at the entry ranging from 0.07 to 0.13m/s and ball diameter is 10mm, 15mm. Also ball filling rate is 33%, 50%.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.1
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• pp.89-97
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• 1995

Experimental study was performed for free convection and ice formation around two horizontal circular tubes which were placed vertically. Temperature and velocity distributions were visualized with real time holographic interferometry technique and tracer method. When water was cooled, super cooled region was formed around cooling pipe. It was found that flow induced by free convection always directed downwards when the coolant temperature was low, while it directed upwards when the coolant temperature was comparably high though it directed downwards initially. Flow phenomena with free convection were investigated in detail with varying cooling rate and length between cooling pipes. And growing process of dense ice was also investigated. Dendritic ice is suddenly formed within a supercooled region, and a dense ice layer begins to develop from the cooling wall.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.783-788
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• 1995

Cooked rices were frozen at four different rates(3, 5, 7 and 12 hr) of maximum ice crystal formation zone and stored at $-20^{\circ}C\;and\;-70^{\circ}C$ for 3 months. Freezing rate, storage temperature and storage period all affected the degree of retrogradation of cooked rice. As the maximum ice crystal formation zone increased from 3 hrs to 12 hrs, the degree of retrogradation of cooked rice increased from 14.9% to 40.0%. Further retrogradation occurred during the freezing storage and cooked rice stored at $-20^{\circ}C$ retrograded faster than that held at $-70^{\circ}C$. The hardness and adhesiveness of frozen cooked rice thawed in $40^{\circ}C$ water were measured. Hardness of the frozen cooked rice was higher than that of non-frozen sample and was higher at lower freezing rate. However, the hardness of cooked rice decreased after 3 months of storage. On the other hand, the adhesiveness decreased during the freezing processing, and adhesiveness decreased more rapidly at a higher freezing rate. However, the adhesiveness of cooked rice increased after 3 months of the storage, and the level of decrease was higher at $-70^{\circ}C$ than at $-20^{\circ}C$. After 3 months of storage, ice crystal size of frozen cooked rice became larger by recrystalization than that of frozen sample prior to storage. Microstructure of cooked rice was damaged by ice crystal formation and its growth when observed by scanning electron microscope.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.65-72
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• 2020

A refrigerator equipped with an ice dispenser has ice cubes in its ice bucket to discharge the required amount of ice. On the other hand, the ice cubes in the bucket may clump together if the refrigerator is filled with ice and is not used for a long time or during normal operation. Although a mechanism for separating the ice mass is provided, the ice mass cannot be removed completely if the ice blocking is severe. To solve this problem, after investigating the existing research on the process of ice entanglement and the separation force, this study tested ice extraction under a range of conditions of artificially entangled ices. In this process, new mechanisms are proposed to resolve the problem of existing ice storage features that prevent the extraction of ice and to expand the working radius of the icebreaking mechanism for full extraction. The prototype of the proposed mechanism was also fabricated in an actual refrigerator. As a result, the proposed shape and mechanism could extract the ice cubes in the bucket completely, while the existing ice dispenser could extract only 65%.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.2
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• pp.128-136
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• 2008

It is necessary to estimate the cooling load of the next day for effective control of ice thermal storage system. In this paper, new methodology is proposed to estimate the cooling load using design parameters of building and predicted weather data. Only six input parameters such as sensible heat coefficient and constant, latent heat coefficient and constant, maximum and minimum temperature are necessary to obtain hourly distribution of cooling load for the next day. Two benchmarking buildings(hospital and research institute) are selected to validate the performance of the proposed method, and the estimated cooling loads in hourly and daily bases are calculated and compared with the measured data for E hospital. The estimated results show fairly good agreement with the measured data for both buildings.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.6
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• pp.609-615
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• 2000

The energy conservation is one of the most important issues in recent years. Especially, the energy conservation through improved control strategies is one of the most highly possible area to be implemented in the near future. The energy conservation of the ice storage system can be accomplished through the improved control strategies. A real time building load prediction algorithm was developed. The expected highest and the lowest outdoor temperature of the next day were used to estimate the next day outdoor temperature profile. The measured dry bulb temperature and the measured building load were used to estimate system parameters by using the on-line weighted recursive least square method. The estimated hourly outdoor temperatures and the estimated hourly system parameters were used to predict the next day hourly building loads. In order to see the effectiveness of the building load prediction algorithm, two different types of building models were selected and analysed. The simulation results show less than 1% in error for the prediction of the next day building loads. Therefore, this algorithm may successfully be used for the development of improved control algorithms of the ice storage system.