• 제목/요약/키워드: Thermal storage efficiency

검색결과 202건 처리시간 0.031초

실험 저장조내의 유입구 형상변화에 따른 열 저장효율에 관한 실험적 연구 (Experimental Study on the Thermal Storage Efficiency Through Variable Porous Mainfolds in a Test Storage Tank)

  • 박이동;황성일;최영일
    • 태양에너지
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    • 제9권3호
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    • pp.37-43
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    • 1989
  • This paper dealt with thermal storage efficiency due to difference ($T_{\infty}-Ti$) between the mean temperature of water in the storage tank [$0.5m{\times}0.5m{\times}1.0m$] and the temperature of water flowing into the tank, flow rate of water flowing into the tank and shape of porous manifold which water flow into the tank through. As results of experiments; (1) When the flow rate was constant and the diameter of porous section decreased by 8mm, 6mm, and 4mm, the thermal storage efficiency increased. (2) When the diameter of porous section was constant and the difference ($T_{\infty}-Ti$) between the mean temperature of water in the storage tank and the temperature of water flowing into the tank increased by -30, -20, -10, 5, 10, 15 ($^{\circ}C$), the thermal storage efficiency increased. (3) When the($T_{\infty}-Ti$) was constant and the flow rate decreased by 0.8, 0.4, 0.25(LPM), the thermal storage efficiency increased. (4) When the shape of porous section was rigid, the thermal storage efficiency was the most effective, and with establishing flexible porous section or mesh, the effective thermal storage efficiency was obtained.

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성층 온수 저장 중 과도 열거동과 축열효율에 관한 연구 (A Study on Transient Thermal Behavior During the Charging Process in a Stratified Water Storage Tank and Its Storage Efficiency)

  • 박이동;주용진;김영헌
    • 태양에너지
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    • 제17권3호
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    • pp.13-21
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    • 1997
  • 장기 성층 온수 저장조 내의 중간 경계면에서 전달되는 열량을 예측하기 위하여 이론식을 유도 확립하고 이론적인 축열효율을 구하였다. 그리고 이론 축열효율값과 비교 고찰하기 위하여 여러 실험 조건을 통한 실제 축열효율을 구하였고, 저장조 내의 중간 경계면에서 일어나는 혼합정도를 효과적으로 해석하기 위하여 유효 열확산 계수를 정량화하였다. 중간 경계면에서 열전도에 의한 손실이 일회 충수 시간이 짧을수록 즉, Pe 수가 증가할 수록 많이 발생함을 알았다.

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스크류 캡슐형 밀폐식 빙축열시스템의 성능시험에 관한 연구 (Study on the Performance Testing of the Closed Ice Thermal Energy Storage System using Screw Capsules)

  • 김경환
    • 한국태양에너지학회 논문집
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    • 제26권4호
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    • pp.39-45
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    • 2006
  • 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 efficiency and thermal characteristics of the closed ice thermal energy storage system using screw capsules. The measured thermal energy storage density is about 18.4 USRT-h/m3 (=232.9 MJ/m3), which is higher than 13.0 USRT-h/m3 (=164.6 MJ/m3), a low criterion of normal performance. And The efficiency of the discharging process and the total energy utilization is 96.2% and 2028.4 kcal/kWh respectively.

지하 열에너지 저장 기술 및 스웨덴 암반공동내 열수 저장 사례 (Technologies of Underground Thermal Energy Storage (UTES) and Swedish Case for Hot Water)

  • 박도현;김형목;류동우;최병희;선우춘;한공창
    • 터널과지하공간
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    • 제22권1호
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    • pp.1-11
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    • 2012
  • 열에너지 저장은 고온 또는 저온의 열에너지를 임시 저장하는 것으로서 에너지 수요와 공급 사이의 불균형을 줄일 수 있고, 이를 통해 에너지를 절약하고 에너지 이용효율을 향상시킬 수 있다. 특히 간헐적으로 에너지를 생산하는 신재생에너지의 경우 에너지 저장 장치와의 조합은 필수적이다. 또한 지하 암반의 낮은 열전도도와 높은 열용량을 이용하여 지하에 열에너지를 저장하는 경우 열손실을 최소화하여 추가적인 효율 향상이 기대된다. 본 고에서는 지하 열에너지 저장 기술을 조사 분석하고 스웨덴에 암반공동내 열에너지 저장 사례를 소개하였다.

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

  • 최우석;박이동;김철주;황영규
    • 한국에너지공학회:학술대회논문집
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    • 한국에너지공학회 1995년도 춘계학술발표회 초록집
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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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Packed Bed 태양에너지 저장시스템의 열성능에 관한 수학적 시뮬레이션 (Mathematical Simulation on Thermal Performance of Packed Bed Solar Energy Storage System)

  • 아닐쿠마르;김만회
    • 한국수소및신에너지학회논문집
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    • 제26권4호
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    • pp.331-338
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    • 2015
  • Solar air heaters (SAHs) are simple in design and widely used for solar energy collection devices, and a packed bed is one of typical solar energy storage systems of thermal energy captured by SAHs. This paper presents mathematical modeling and simulation on the thermal performance of various packed bed energy storage systems. A MATLAB program is used to estimate the thermal efficiency of packed bed SAH. Among the various packed bed energy storage systems considered, the wire mesh screen packed bed SAH shows the best thermal efficiency over the entire range of design conditions. The maximum of thermal efficiency of packed bed SAH with wire mesh screen matrices has been found to be 0.794 for Re=2000 - 20000 and ${\Delta}T/I=0.002-0.02$.

플라스틱 온실(溫室)의 열저장(熱貯藏) 시스템의 개발(開發)에 관(關)한 연구(硏究)(II) -수경재배용(水耕栽培用) 태양열(太陽熱) 온실(溫室) 시스템의 열적(熱的) 성능(性能)- (Development of Thermal Storage System in Plastic Greenhouse(II) -Thermal performance of solar greenhouse system for hydroponic culture-)

  • 김용현;고학균;김문기
    • Journal of Biosystems Engineering
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    • 제15권2호
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    • pp.123-133
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    • 1990
  • Thermal performance of a solar heating plastic greenhouse designed for a hydroponic system was studied. The system was constructed with the air-water heat exchanger and thermal storage tank that were combined with hydroponic water beds. Experiments were carried out to investigate the daily average heat stored and released in thermal storage tank, average solar energy collection efficiency, average coefficient of performance, average oil reduction factor of thermal storage system, and the heat transfer coefficient during the nighttime in plastic greenhouse. The results obtained in the present study are summarized as follows. 1. Daily average heat stored in thermal storage tank and released from the thermal storage tank was 1,259 and $797KJ/m^2$ day, respectively. 2. The average solar energy collection efficiency of thermal storage tank was 0.125 during the experiment period. And the average coefficient of performance of thermal storage system in plastic greenhouse was 3.6. 3. The average oil reduction factor of thermal storage system and the heat transfer coefficient during the nighttime in plastic greenhouse were found to be 0.52 and $4.3W/m^2\;hr\;^{\circ}C$, respectively.

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지하대수층을 이용한 축열시스템의 설계 (I) : 등온해석 (Design of an Aquifer Thermal Energy Storage System (I) : Isothermal Analysis)

  • 송영길;이관수;이태희;김양현
    • 설비공학논문집
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    • 제5권2호
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    • pp.102-110
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    • 1993
  • An isothermal analysis was conducted to develop the design tool of an aquifer thermal energy storage system. Taejeon aquifer was chosen for the analysis, and the variation of FRE(Fluid Recovery Efficiency) with respect to the aquifer natural velocity and thermal load were investigated. The analysis results were compared with those of ATESSS(Aquifer Thermal Energy Storage System Simulator) and agreed within 2% of discrepancy. It is recommended, based on the result of this study, that the system may be suitable for a large volume of hot or chill thermal energy storage system, such as for district heating or cooling.

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지하대수층을 이용한 축열시스템의 설계(II) : 열해석 (Design of an Aquifer Thermal Energy Storage System(II) : Thermal Analysis)

  • 이관수;이태희;송영길
    • 설비공학논문집
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    • 제6권3호
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    • pp.315-324
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    • 1994
  • The energy recovery efficiency(ERE) of an aquifer thermal energy storage system was calculated using curvilinear coordinate. The results of the calculation were compared with the experimental results, and agreed within 11% of the discrepancy. The variation of ERE was investigated as a function of the underground water natural velocity, the amount of the stored energy, and period of the energy recovery. The slower the natural velocity and shorter the recovery period, the higher ERE was yielded. Also it was found that increase in the amount of energy storage yields higher ERE, and carries out less influential ERE to the natural velocity. Reiterative usage of the aquifer as a thermal storage tends to gradually increase ERE. The result of this study implements that the aquifer thermal energy storage system is suitable for large cooling/heating loads, such as district cooling/heating.

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밀폐식 빙축열시스템의 축열 및 방열과정에 관한 실험 (Experiment on the Charging and Discharging Processes of a Closed Ice-Thermal-Energy-Storage System)

  • 김경환;윤영환;김연규
    • 에너지공학
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    • 제16권4호
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    • pp.164-169
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    • 2007
  • 우리나라에서 여름철 피크전력부하의 감소는 매우 중요하다. 정부는 피크전력부하를 저감하기 위하여 많은 지원 정책과 법률을 제정하여 시행하고 있다. 그리고 빙축열시스템은 이런 대안 중의 하나로서 알려지고 있다. 이 논문의 목적은 축열운전, 병렬운전과 축열조 단독운전이 수행된 밀폐식 빙축열시스템의 축열조 성능과 전체 효율을 평가하는 것이다. 설계조건에서 운전된 빙축열시스템의 자료를 이용하여 축열조의 축열밀도와 방냉효율 그리고 시스템의 총괄에너지 이용효율을 계산하면 $18.4\;USRT-h/m^3$, 96.2% 그리고 2028.7 kcal/kWh이다. 빙축열시스템의 축열조에 공급되는 에너지를 설계조건보다 많게 공급하면 과냉각효과에 의해 설계조건보다 시스템 효율이 낮게 평가되어진다.