• Title/Summary/Keyword: heat storage

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Heating Characteristics of Ondol using Heat Pump-Latent Heat Storage System (열펌프-잠열축열시스템을 이용한 온돌의 난방특성)

  • Kim, M.H.;Song, H.K.
    • Solar Energy
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    • v.20 no.3
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    • pp.1-9
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    • 2000
  • In these days the hot water circulating Ondol using the fossil fuel boiler is the heating system for the most of the Korean residents. Then it is installed without the heat storage medium in the Ondol heating layer, but the Korean traditional Ondol had been composed with the heat storage medium. The Ondol room without heat storage medium could not be comfortable because the room air temperature is not only changed unstably but also it has a defect too much fuel consumption. Therefore in this study the heat pump-latent heat storage Ondol as the new type of Ondol system was developed to solve these problems mentioned above, and the COP of the heat pump (Coefficient Of Performance), the latent heat storage characteristics in the new type of Ondol system and the temperature variation in the Ondol room with the ambient temperature were analyzed.

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Design of a Solar Thermal Storage System Employing Heat Pipes and Molten Salts (히트파이프와 용융염을 사용하는 태양열 축열조의 설계)

  • Lee, Jung-Ryun;Boo, Joon-Hong
    • 한국태양에너지학회:학술대회논문집
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    • 2011.04a
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    • pp.86-91
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    • 2011
  • Thermal design was conducted for a solar thermal storage system in a medium-temperature range between $200^{\circ}C$ and $400^{\circ}C$. The system was composed of heat pipes as heat carrier and molten salts as phase-change storage material. Each heat pipe penetrated through the storage system and had two heat-exchanging sections at both ends to interact with high-and low-temperature steams, while it exchanged heat with molten salts in the middle section. During a heat-storage mode, the heat pipes transferred heat from the hot steam at one side to the molten salts and it transferred heat from the molten salt to the cold steam at the other side during the heat-dissipating mode. A tube-bank type heat exchanger theory was applied to this design task to meet the required inlet and outlet temperatures of the steams depending on the operation modes. Several design variables were considered including the lengths of evaporator and condenser of a heat pipe, traverse and longitudinal pitches of the pipe, and the number of rows of the heat pipes for two different molten salt baths. An optimum design results were presented with discussion.

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A study on the Thermal Characteristics of a Thermal Storage Tank for using Gravels (자갈식 축열조의 축열특성에 관한 연구)

  • Park, Jung-Won;Park, Bong-Kyu;Ahn, Sang-Kyu
    • Solar Energy
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    • v.12 no.1
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    • pp.81-87
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    • 1992
  • The purpose of this study was to investigate the fluid flow characteristics of heat storage in sensible heat storage system for use In cooling and heating of buildings. Heat storage material was gravels and experiments were performed in the condition of constant temperature. The experimental parameters were fluid velocity and size of gravels. The experimental results of the heat storage quantity and the heat storage efficiency by the variation of packing size and fluid velocity were as the follows : The maximum value of the heat storage capacity and heat storage efficiency and the minimum arriving time for maximum heat storage were observed when the packing ratio was 72.5% and the fluid velocity was 0.14m/s.

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An Effect of Heat Input on Thermal Storage for Horizontal Thermal Storage Tank with Heat pipe (열 파이프용 수평 축열조에서의 열 입력이 축열에 미치는 영향)

  • 최우석;박이동;김철주;황영규
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 1995.05a
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    • pp.69-76
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    • 1995
  • 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. Therefore Arrangement of heating pad affects thermal flow and thermal storage efficiency. So, if effective arrangement is decided for condition of constant number of heating pad, the more rapid thermal flow effect and higher thermal storage efficiency is obtainable by active heat transfer. In this experiments, number of heating pad is ranged from three, five and nine, and when number of heating pad is constant, arrangement are two types of concentration-type and dispersion-type. As a result, for the case of concentration-type of heating pad, strong entrainment take place in horizontal thermal storage tank with heat pipe by active heat transfer and in the constant number of heating pad, the concentration-type has the higher efficiency with about 5∼6% than the dispersion-type. Therefore, when heating pad is equipted to horizontal thermal storage tank with heat pipe, concentration-type of heating pad is an efficient design in constant number. of heating pad.

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Analysis on Cascade Cycle Heat Pump Application as Night Storage Heater (심야전력을 이용한 Cascade Heat Pump Cycle의 운전결과 분석)

  • JUNG, H.;HWANG, S.W.;LEE, C.H.
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.1
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    • pp.113-118
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    • 2011
  • To analyze and verify the effect of replacing thermal storage heater by a cascade cycle heat pump using midnight electricity was installed and tested at a customer's house in Wonju, Korea. The electric night storage heater is consist of 30kW electric heater and 2,700 liters of thermal storage water tank to supply hot water for warming house floor. The power for electric heater was cut off and hot water was only generated by cascade cycle heat pump. Current thermal storage water tank was not eliminated and electric heater wiring was modified. Some operation logic of the heat pump was also modified for proper operation. The required capacity of the heat pump and hot water temperature for given warming condition were estimated. The estimated capacity of heat pump was about 19kW and estimated hot water temperature for proper heating was at least $75^{\circ}C$.

A Study of Storage Type Cooling and Heating System by Heat Pipe (히트파이프를 이용한 축열식 냉.난방 시스템에 관한 연구)

  • Kim, Seong-Sil;Harm, Seong-Chol;Lee, Yang-Ho;Choi, Byoung-Youn
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.3-8
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    • 2006
  • The heat pump system is attractive alternatives to conventional heating and cooling systems owing to their higher energy utilization efficiency. The thermal loads of commercial and institutional buildings are generally cooling-dominated. In this study have been developed ice storage type heat pump system for cooling and heating by heat pipe. This system was practiced performance test on evaluation criteria for heat storage systems. Accomplished the actual proof examination and looked into the performance of the system. In this study, measurement and analysis of ice storage type heat pump system for cooling and heating by heat pipe. The heat pump unit COP appears 3.05 for cooling and 4.20 for heating. As a result, the method to energy saving and to using a substitute energy actively that is heat pump cooling & heating system is expected by heat pipe. Thermal storage capacity appears $19.5RTH/m^3$ for cooling.

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HEAT REMOVAL TEST USING A HALF SCALE STORAGE CASK

  • Bang, K.S.;Lee, J.C.;Seo, K.S.;Cho, C.H.;Lee, S.J.;Kim, J.M.
    • Nuclear Engineering and Technology
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    • v.39 no.2
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    • pp.143-148
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    • 2007
  • Spent nuclear fuel generated at nuclear power plants must be safely stored during interim storage periods. A dry storage cask to safely store the spent nuclear fuel should be able to adequately emit the decay heat from the spent nuclear fuel. Therefore, heat removal tests using a half scale dry storage cask have been performed to estimate the heat transfer characteristics of a dry storage cask under normal, off-normal, and accident conditions. In the normal condition, the heat transfer rate to an ambient atmosphere by convective air through a passive heat removal system reached 83%. Accordingly, the passive heat removal system is designed well and works adequately. In the off-normal condition, the influence of a half blockage in the inlet on the temperature appears minimal. In the accident condition, the temperature rose for 12 hours after the accident, but the temperature rise steadied after 36 hours.

Improvement of Heat Pump Heating Performance by Selective Heat Storage Using Air Heat of Inside and Outside Greenhouse (온실 내외부 공기열의 선택적 축열에 의한 히트펌프 난방성능 개선)

  • Kwon, Jin Kyung;Kim, Seung Hee;Jeon, Jong Gil;Kang, Youn Koo;Jang, Kab Yeol
    • Journal of Bio-Environment Control
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    • v.26 no.4
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    • pp.353-360
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    • 2017
  • In this study, the design and performance test of the air to water heat pump capable of producing hot water for greenhouse heating by using the surplus solar heat inside the greenhouse and the air heat outside greenhouse as the selective heat source were conducted. The heat storage operations using the surplus solar heat and the outside air heat were designed to be switched according to the setting temperature of the greenhouse in consideration of the optimum temperature range of the crop. In the developed system, it was possible to automatically control the switching of heat storage operation, heating and ventilation by setting 12 reference temperatures on the control panel. In the selective heat storage operation with the surplus solar heat and outside air heat, the temperature of thermal storage tank was controlled variably from $35^{\circ}C$ to $52^{\circ}C$ according to the heat storage rate and heating load. The heat storage operation times using the surplus solar heat and outside air heat were 23.1% and 30.7% of the experimental time respectively and the heat pump pause time was 46.2%. COP(coefficient of performance) of the heat pump of the heat storage operation using the surplus solar heat and outside air heat were 3.83 and 2.77 respectively and was 3.24 for whole selective heat storage operation. For the comparative experiment, the heat storage operation using the outside air heat only was performed under the condition that the temperature of the thermal storage tank was controlled constantly from 50 to $52^{\circ}C$, and COP was analyzed to be 2.33. As a result, it was confirmed that the COP of the heat storage operation using the surplus solar heat and outside air heat as selective heat source and the variable temperature control of the thermal storage tank was 39% higher than that of the general heat storage operation using the outside air heat only and the constant temperature control of the thermal storage tank.

Performance Analysis of a Panel Type Latent Heat Storage Equipment for Solar Thermal Storage (태양열저장(太陽熱貯藏)을 위한 평판형잠열축열장치(平板形潛熱蓄熱裝置)의 성능분석(性能分析))

  • Kim, Y.B.;Ju, E.S.;Yun, Y.D.;La, W.J.
    • Journal of Biosystems Engineering
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    • v.16 no.3
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    • pp.290-297
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    • 1991
  • For the efficient utilization of the solar thermal energy to overcome the time gap between to supply and demand, an efficient heat storage technique, especially high density-latent-heat storage system, is necessary. In this study, the performance of a panel type latent heat storage equipment during heat discharging process was analyzed theoretically and experimentally. In order to find out the performance of the system, computer simulation programs were developed by finite difference method. The governing equations were constructed by two dimensional heat conduction model with moving boundary. The results of the experimental and the theoretical analysis were reasonably well agreed. The efficiencies of the double pipe type and the panel type latent heat storage equipment were compared.

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Numerical Analysis on the Performance for Automobile Heat Storage System Using Phase Change Materical (상변화물질을 이용한 자동차용 열저장 시스템의 성능을 위한 수치 해석)

  • 이관수;김혁제;백창인;송영길;한창섭;김등진
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.3
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    • pp.187-198
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    • 1996
  • In this study, the performance of an automobile heat storage system using PCM is numerically simulated. For the analysis of system performance. The phase-change of the PCM and the transient forced convective heat transfer for the HTF are considered simultaneously as a conjugate problem. The phase-change behavior is effectively analyzed using a concept of thermal resistance. From the correlations of phase change rate and heat transfer due to the variations of flow rate of HTF around PCM, the automobile heat storage system performance is predicted. The present results amy be used as the fundamental information for the design of automobile heat storage system.

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