• Transactions of the Korean hydrogen and new energy society
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• v.30 no.4
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• pp.376-383
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• 2019

This paper presents of thermal performance analysis by using mathematical models for a compound parabolic collector (CPC) system employing heat storage tank. The thermal performance including insolation energy, heat loss from collector system, useful energy, collector efficiency, and temperature of storage tank were theoretically investigated through a year using monthly-average meteorological data at Seoul. The simulated results showed that the CPC systems are suitable for the applications of higher temperature than flat plate collector (FPC) systems.

• Solar Energy
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• v.18 no.1
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• pp.99-109
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• 1998

The study on ice thermal storage system is to improve total system performance in actual air-conditioning facilities. To attain the high efficiencies in ice thermal storage system, the improvement of thermal stratification is essential, therfore the process flow must be piston flow in thermal storage tank. Ice packing factor is better on condition that the inflowing temperature is low, the flow direction in the thermal storage is upward and the cylindericalthermal storage type is used. This result shows that the cylinderical ice storage tank has better storage capacity than the rectangular type in case of the same porocity.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.268-273
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• 2001

A fundamental study on the harvest-type ice storage system applied ice making method in-water and its temperature characteristics in ice storage system was performed experimentally of the charge and discharge of cold. This paper is concerned with the development of a new method for making and separating ice and saving floated ice by installing an evaporation plate at in-water within a storage tank. In a conventional harvest-type ice storage system, a tank saves ice by separating a formed ice from an installed evaporation plate, which is located above an ice storage tank as an ice storage system. A new harvest-type method shows very good heat transfer efficiency than a convectional method. It is because the evaporation panel is directly contacted with water in a storage tank. Also, at a conventional system a circulating pump, a circulating water distributor and a piping are installed, but these components are not necessary in a new method. In this study two kinds of ice storage systems are experimentally investigated to study the thermal characteristics of ice storage tanks.

• Solar Energy
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• v.17 no.3
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• pp.13-21
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• 1997

In this study, the theoretical equation of thermal storage efficiency was established to applied long term hot water storage system. The, effective thermal diffusivity and storage efficiency were, measured through the experiment to predict the degree of mixture in thermal storage tank. The effective thermal diffusivity was inversely preportional to the storage efficiency. The most effective storage efficiency was obtained under condition of low flow rate and using the perforated distributor.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.4
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• pp.337-344
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• 2000

The present study describes a one-dimensional modeling of encapsulated ice storage tanks. The thermal transmittance of capsules in this model uses the results from the Arnold's experimental $study^{(2-3)}$.In this model, ice storage tank is partitioned by several control volumes for the analysis, each having same number of capsules. The model is validated by the comparison of the measured data from an ice storage tank installed at a building with the capacity of 1200 ton-hrs and the simulated results with the same inlet brine temperature conditions into the tank.

• Solar Energy
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• v.5 no.2
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• pp.35-45
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• 1985

A solar hot water storage tank was designed and constructed to examine the heat exchange performances on load side for the solar thermal storage in a single loop solar water heating system. In the tank helically coiled tube was immersed. The hot water was circulated from either top or bottom. The circulation flow rate was varied from 500 ml/min to 20,000 ml/min. The effect of flow rate was observed. The thermal performances according to the flow rate and flow direction were examined. The temperature distributions in the tank and inside of the tubes were plotted along the process of cooling.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.7
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• pp.322-328
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• 2014

Return piping is used in a solar combi-system for heating and hot water supply. When the temperature of the lower side of a storage tank is low due to hot water usage, the returned hot water after heating is mixed with the lower side cold water of the tank, and the useful energy is reduced. We studied the degree of thermal stratification in the tank, using either a diffuser or a manifold to prevent mixing. Using the diffuser, mixing starts from the bottom of the storage tank. On the other hand, the manifold has the marked effect of preventing mixing. As a result of experiments with changing the diameter and number of holes in the manifold, the optimum condition is 8.5 mm diameter and 96 holes, under the condition of 0.3 lpm.

• Transactions of the KSME C: Technology and Education
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• v.2 no.1
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• pp.65-72
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• 2014

The purpose of this study is to design a heat insulator for reducing available energy loss in stratified thermal storage tank. Heat insulator is operated by buoyancy effect from density difference between hot and cold water without extra equipment. Analysis model using the Matlab Simulink was developed to estimate the internal temperature distribution in thermal storage tank and also used to select proper material and thickness of the heat insulator. Operational feasibility was confirmed through reduced scale experiment. As a result, heat insulator can effectively delay the formation of thermal boundary layer between hot and cold water. In reduced scale experiment, heat insulator can preserve additional 1540J of available energy. When applied to the real thermal storage tank, increase of 6% thermal storage efficiency can be expected.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.108-113
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• 2004

Korea Gas Corp. has developed the design technology of the LNG storage tank. The membrane to be applied inside of the LNG storage tank is provided with corrugations to absorb thermal contraction and expansion caused by LNG temperature changes. It is very important to measure their thermal strains under LNG temperatures by analytical and experimental stress analysis of the membrane. We have developed a stress measurement system using strain gages and measured the strain during cooldown and storing the LNG. We also analyzed the measured data by comparison with the FEM data. On the basis of these results, we could design and assure the application of the Kogas Membrane to large scale LNG storage.

• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.45-54
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• 2007

For a conventional natural-circulation type solar water heater, the pressure head is limited by the height between the storage tank and hot water tap. Therefore, it is difficult to provide sufficient hot water flow rate for general usage. This study deals with a design modification of the storage tank to utilize the tap-water pressure to increase hot-water supply Based on fluid dynamic and heat transfer theories, a series of modeling and simulation is conducted to achieve practical design requirements. An experimental setup is built and tested and the results are compared with theoretical simulation model. The storage tank capacity is 240 l and the outer diameter of piping was 15 mm. Number of tube turns tested are 5, 10, and 15. Starting with initial storage tank temperature of $80^{\circ}C$, the temperature variation of the supply hot water is investigated against time, while maintaining minimum flow rate of 10 1/min. Typical results show that the hot water supply of minimum $30^{\circ}C$ can be maintained for 34 min with tap-water supply pressure of 2.5 atm, The relative errors between modeling and experiments coincide well within 10% in most cases.