• 연구논문집
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• s.30
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• pp.15-23
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• 2000

In this study, develop the thermal pump using water evaporation and condensation. Vapor from heating room moves up to pumping room and press the water of pumping room. Consequently water is pumped out to water tank. Then hot vapor direct contact with cold water in condensing room after pumping process. At this time, pressure of condensing room is down to-5kPa and suck in water of tank. This pump executes self ping and good durability because of no mechanical moving parts. Thermal pump is pumped cyclic so that, this pump is not used single. Therefore thermal pump of hot water boiler used to multi-stage for stable pumping rate. As the result of performance test, the developed thermal pump proves pumping action of water evaporation/condensation. And total volume flow rate is 500liter during one hour. If three thermal pump is installed parallel, this pump can use to the hot water boiler in the 300,000kcal/h class.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.6
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• pp.503-511
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• 2002

Heat flow characteristics during hot water extraction process was studied experimentally. Data were taken at various outlet port type for the fixed inlet port type, inlet-outlet temperature differences and mass flow rates. In this study, the temperature distribution in a storage tank and an outlet temperature were measured to predict a degree of stratification in the storage tank, and a useful rate of hot water was analysed with respect to the variables dominating a extraction process. Experimental results show that the degree of stratification and useful rate of hot water are all high in a low flow rate in case of using modified distributor I (MDI) as the outlet port type.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.1 no.1
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• pp.9-20
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• 1989

This paper presents an analysis to predict thermal behaviors of water in ice storage tank during the coldness release process. To deal with complicated transient phenomena due to ice-water phase change and the density inversion, a theoretical model which consists of initial perfectly mixed, stratified and thermal diffusion state was introduced and a criterion on the growth of thermal boundary layer was developed. The analysis includes considerations on the type of ice-making heat exchanger, refrigerator on/off and tank arrangement. Also, discussions on the various parameters and operating conditions which have influence on the performance of the system were made. Finally, simulated results were shown, which agreed with experiments in trends reasonably.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.689-692
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• 2006

The crack of concrete induced by the heat of hydration is a serious problem, particularly in massive concrete structures. In order to control the temperature crack of massive concrete, the selection of appropriate materials like low heat cement, mixture materials, etc. is essential. In tills study, mix proportion using low heat portland cement and lime stone powder was designed and the best mix proportion, B-1, was selected. When bottom slab of the #219 LNG tank in Incheon was constructed, concrete temperature was measured. And thermal stress was analyzed about bottom slab of the LNG tank. As results of the thermal analysis, crack index was 1.60 in bottom slab and satisfied with construction specifications(over 1.0).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.7
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• pp.625-631
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• 2015

In this study, a numerical analysis on the discharging performance of a thermal storage tank completely filled with packing modules is investigated. The enthalpy-porosity method is adopted to analyze phase change phenomenon. Using this method, the melting process of a packing module in the thermal storage tank was studied as the HTF (heat transfer fluid) flows down from the top of the tank at the discharging mode. There are some design factors such as the module arrangement and the number of modules, but this study focuses on the effects of varying the flow rate of the HTF on the outlet temperature of the HTF, molten fraction, and thermal storage density. As the flow rate increases, the outlet temperature of the HTF gets higher and the total melting time of the PCM decreases. Additionally, the thermal storage density is increased so that it reaches about 93% for the desired value.

• Journal of Energy Engineering
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• v.16 no.4
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• pp.164-169
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• 2007

The decrease in the summer peak electric load in our country is very important. The government has arranged and implemented a lot of support policies and statutes to decrease the peak electric load. And the ice-thermal-energy-storage system is known as one of the alternatives. The purpose of this paper is to evaluate the performance and the total efficiency of its storage tank, conducting the charging operation, the parallel operation and the single operation of a storage tank. The thermal energy density stored and discharging efficiency of a storage tank and the efficiency of total energy utilization of system are $18.4\;USRT-h/m^3$, 96.2% and 2028.7 kcal/kWh under the operation of design condition. When the storage tank is supplied more ice thermal energy than design condition, it is estimated that the efficiency of system are lower than the design condition by the supercooled effect.

• 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.

• Journal of Energy Engineering
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• v.14 no.1
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• pp.62-71
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• 2005

An experimental study on thermal mixing of steam jet condensation through the I-Sparger of APR1400 design using B&C (Blowdown and Condensation) test facility. Due to the limit of the steam supply capability of the pressurizer, transient thermal mixing experiments were conducted. Temperature distributions in the quench tank were measured using thermocouples located at various positions. From the experimental data, local temperature variations for various locations and vertically cross-sectional temperature distributions for several times were depicted and presented. The result shows the characteristics of thermal mixing of the I-Sparger depending on the design features of the I-Sparger.

• Solar Energy
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• v.16 no.2
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• pp.39-47
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• 1996

The horizontal thermal storage tank with heat pipe which is suitable for the sensible heat storage system is able to store a hot water from the heat source such as heating pad efficiently and to supply a hot water to load rapidly. And arrangement of heating pad play an important role in thermal flow and thermal storage efficiency. In this experiments, number of heating pad is ranged from three, five and nine, and when there is no change on number of heating pad, arrangements are two types of concentration-type and dispersion-type. Strong entrainment take place in the case of concentration-type of heating pad, and rapid temperature rise(${\Delta}{\doteqdot}1.6{\sim}3.2^{\circ}C$) in the tank is obtainable on the concentration-type than dispersion-type. In the constant number of heating pad, the concentration-type has the higher efficiency with about $5{\sim}6%$ than the dispersion-type Therefore, concentration-type of heating pad is an efficient design in constant number of heating pad.

• 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.