• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1996년도 추계학술발표회 논문집
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• pp.193-205
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• 1996

This paper deals with experimental study on thermal characteristics that a cooling fluid is affected to ice ball as being measuring the temperature in storage tank and ice ball governing the rate of heat storage. Distributor was taken as inlet geometry factor. flow rate of cooling fluid which was a brine were 2, 4, and 6LPM, and 8, 10, and 12$^{\circ}C$ in the temperature difference for dynamic factors with respect to three ice ball types(103, 96, 76mm). In case of in flowing cooling fluid, since inertia force is suppressed by lower flow rate the amount of heat was transferred to ice ball by heat conduction high because density difference is high. And in case of larger ice ball, a long-term storage was available because reaching time at steady state is relatively long. consequently, smaller ice ball could be suitable to a short-term storage.

• 설비공학논문집
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• 제11권3호
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• pp.401-413
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• 1999

An ice storage cooling facility with cooling capacity of 150㎾ has been constructed for the purpose of developing optimal design and control strategy for an ice storage system. As the first step to this purpose, a computer program has been developed to simulate the operation of the ice storage system and examined precisely by comparing the results with those measured from the test facility. With the simulation program verified from the comparison, a design procedure has been developed to determine the minimum capacity required for each operation strategy available commercially. It is shown that the minimum sizes of the chiller and the storage tank are strongly dependent on the control strategy, i.e., chiller priority or storage priority, but less affected by the arrangement method, i.e., chiller upstream or chiller downstream.

• 설비공학논문집
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• 제17권2호
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• pp.156-164
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• 2005

A comparative analysis of an ice storage system has been performed on the operation cost for the four control strategies, i.e., chiller priority and chiller downstream, chiller priority and chiller upstream, storage priority and chiller upstream, storage priority and chiller downstream. Main components of the ice storage system are an ice-on-coil storage tank and a screw compressor chiller. With the simulation program, the operation cost has been evaluated from the economics of an ice storage system. It is found that the operation cost of the ice storage system is strongly dependent on the control strategy, i.e., chiller priority or storage priority, but less affected by the arrangement method, i.e., chiller upstream or chiller downstream. In case of the maximum load day, the control strategy with chiller priority and chiller upstream is supposed to obtain the reduction of operation cost. However, it is found that the control strategy with storage priority and chiller downstream is the best economical operation for most summer seasons except the maximum load day.

• 태양에너지
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• 제17권2호
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• pp.75-89
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• 1997

동적형(Dynamic type) 빙축열시스템의 빙축열조에서 단열조건과 비단열조건인 경우 각각 얼음충진율(Ice Packing Factor), 분산유체의 온도 및 유량의 변화에 따른 실험을 수행하였다. 실험시간이 경과함에 따라 빙축열조의 수직방향으로 온도성층화가 나타났으며 분산유체의 유입온도가 높고 유입유량이 많을수록 상부영역에서 온도분포는 크게 변화하였고 온도성층화에 도달하는 시간도 단축되었다. 또한 얼음충진율이 작은 경우가 온도성층화를 이루는 시간이 짧았고 상하부 온도차가 급격히 커진 것 알 수 있었다. 그리고 단열의 경우가 비단열의 경우보다 모든 조건하에서 조금 높은 온도분포를 나타내었으며 온도성층화에 소요되는 시간도 조금 단축되었다. 빙축열조내의 수직방향의 평균온도 상승은 얼음충진율이 낮고 유량이 많을수록 커졌으며 총방열에너지에 대한 잠열에너지의 비($E_{\lambda}/E_[tot}$)는 약 80%정도로 나타났다. 또한 유입온도가 높고 유량이 많을수록 잠열에너지의 방출이 빨리 나타났다.

• 한국항해항만학회지
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• 제35권5호
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• pp.365-370
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• 2011

최근 지구 온난화와 더불어 급격한 기후 변화 등으로 여름철 주간 냉방 수요가 급격히 증가하고 있다. 이에 따른 전력 수요량 또한 증가하고 있다. 이런 이유로 세계적으로 에너지 이용 효율 향상에 대한 관심이 높아지고 있고, 최근 국내 및 국외의 축냉시스템을 이용한 주간 전력 피크값을 최소화 하는 연구개발과 실제 적용 사례가 늘어나고 있다. 빙축열시스템의 경우 그 경제적 효과가 높아 그 관심이 높아지고 있는 추세이다. 축냉시스템은 주간 냉방에 사용하는 냉열을 야간에 만들어 탱크에 저장해 두었다가 그것을 낮에 이용함으로써, 갑작스런 부하 증가에 적절히 대응할 수 있는 등 여러 가지 장점을 갖고 있다. 본 실험에서는 슬러리아이스 생성을 위해 냉각표면에서 생성된 슬러리아이스를 분리시키기 위해 유체보다 밀도가 낮은 역전유동 물질을 삽입하여 역전 유동층을 형성하였으며, 역전유동층의 유동에 의해 관군으로 구성되어 있는 냉각튜브 표면에 빙부착이 심화되기 전에 얼음 입자를 분리시켜 수 내지 수십 미크론 단위의 슬러리아이스를 생성하도록 하였다.

• 태양에너지
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• 제19권4호
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• pp.33-43
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• 1999

The study on ice thermal storage system is to improve total system performance and increase the economical efficiency in actual all-conditioning facilities. To obtain the high charging and discharging efficiencies in ice thermal storage system, the improvement of thermal stratification is essential, therefore the process flow must be piston flow in the cylindrical type. With the relation of the aspect ratio(H/D) in the storage tank, the stratification is formed better as inlet flow rate is smaller. If the inlet and the outlet port are settled at the upside and downside of the storage tank, higher storage rate could be obtainable. In case that the flow directions inside the thermal storage tank are the upward flow in charging and the downward in discharging, thermal stratification is improved because the thermocline thickness is maitained thin and the degree of stratification increases respectively. In the charging process, in case of inlet flow rate the thermal stratification has a tendency to be improved with the lower flow rate and smaller temperature gradient in case of inlet temperature, the large temperature difference between inflowing water and storage water are influenced from the thermal conduction. The effect of the reference temperature difference is seen differently in comparison with the former study for chilled and hot water. In the discharging process, the thermal stratification is improved by the effect of the thermal stratification of the charging process.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2004년도 춘계 학술발표회 논문집
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• pp.219-224
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• 2004

The present study was to investigate the heat transfer enhancement effect of coil wire fins in an ice storage system. For the two cases of tubes with internal brine flows, a finned tube with coil wires on its outer surface and a smooth tube, the rates of ice layer were tested and compared for both the icing processes. The coil fins were made of a stainless steel wire with a dia. of 2.0(mm), and the coil had an outer dia. of 10(mm) and a helix angle of 60($^{\circ}$). The experimental results showed that the coil fins could substantially reduce the thermal resistance of the ice layer, and enhance the heat flow rates between the water in the storage tank and the brine. The ice storing time was found to be shortened by 13(%) for the coil fins to get the same amount of ice layer that was built on the smooth tube wall for 10 hours of operation when the same thermal conditions were provided.

• 대한기계학회논문집
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• 제19권10호
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• pp.2647-2656
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• 1995

The present work was performed to axially and radially investigate the local cold storage performance in the cylindrical tank with the spherical capsules inserted n-Tetradecane as a new cold storage material. The local cold storage performance of the capsules in the tank was experimentally investigated for the inlet temperature of -7, -5, -3, 0.deg. C, for the flow rate of 0.95, 1.89, 2.84, 6.00 l/min, and for the diameter ratio of 4.9, 9.0, 13.1. The local cold storage performance in the case of using water applied for the commercial ice-ball system was axially investigated by changing the flow rate only with the inlet temperature of -7.deg. C and the diameter ratio of 9.0 in order to compare with the performance in the case of using n-Tetradecane. For the case of using n-Tetradecane, the difference of cold storage period between the first and the seventh story was increased as the inlet temperature was increased and the flow rate was decreased. The capsules at the center of the tank showed the supercooling and the increased cold storage period compared with the capsules at the wall of the tank due to the small porosity and insufficient cold storage performance at the center of the tank as the diameter ratio is increased. The case using water showed worse cold storage performance due to comparatively large supercooling than the case using n-Tetradecane.

• Journal of Advanced Marine Engineering and Technology
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• 제30권3호
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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%.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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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%.