Journal of the Computational Structural Engineering Institute of Korea (한국전산구조공학회논문집)

Computational Structural Engineering Institute of Korea (한국전산구조공학회)
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Analysis of Microstructure and Thermal Conductivity of Concrete Thermal Energy Storage based on Amount of Graphite Mixture

그라파이트 혼입량에 따른 에너지 저장 콘크리트의 미세구조 및 열전도도 분석

  • Kim, Se-Yun (SB Engineering Technical Research Center) ;
  • Kim, Sung-Jo (Department of Civil and Environmental Engineering, Yonsei University) ;
  • Suh, Jeewoo (Department of Civil and Environmental Engineering, Yonsei University) ;
  • Han, Tong-Seok (Department of Civil and Environmental Engineering, Yonsei University)
  • 김세윤 (에스비엔지니어링 기술연구소) ;
  • 김성조 (연세대학교 건설환경공학과) ;
  • 서지우 (연세대학교 건설환경공학과) ;
  • 한동석 (연세대학교 건설환경공학과)
  • Received : 2021.06.29
  • Accepted : 2021.08.02
  • Published : 2021.10.31
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Abstract

In this study, the microstructure and thermal conductivity correlation was investigated for concrete materials used in concrete thermal energy storage (CTES) among real-time energy storage devices. Graphite was used as admixture to increase the thermal conductivity performance of the CTES. Concrete specimens of 10% and 15% substitution of cement by mass with graphite, as well as ordinary portland cement (OPC) specimens were prepared, and the microstructural changes and effects on thermal conductivity were analyzed. Porosities of OPC and concrete with graphite were compared using micro-CT, and the microstructural characteristics were quantified using probability functions. Three-dimensional virtual specimens were constructed for thermal analysis, to confirm the effect of microstructural characteristics on thermal conductivity, and the results were compared with the measured conductivity obtained using the hot-disc method. To identify thermal conductivity of graphite for thermal analysis, solid phase conductivity was inversely determined based on simulation and experimental results, and the effect of graphite on thermal conductivity was analyzed.

본 논문은 에너지를 실시간으로 저장할 수 있는 저장장치 중 열에너지 저장 콘크리트를 대상으로 재료의 미세구조와 물성(열전도도)의 상관관계를 분석하는 연구를 수행하였다. 에너지 저장 콘크리트의 열전도 성능을 증가시키기 위해 혼화재인 그라파이트(graphite)를 사용하였다. 그라파이트가 시멘트 질량의 10%와 15%를 치환한 시편과 일반 콘크리트(OPC) 시편을 제작하여 그라파이트의 혼입에 따른 미세구조 변화 및 열전도도의 영향을 마이크로 스케일에서 분석하였다. 마이크로-CT를 활용하여 OPC와 그라파이트를 사용한 콘크리트의 공극률을 비교하였으며, 확률함수를 사용하여 미세구조 특성을 정량화하였다. 미세구조 특성 차이가 열전도도에 미치는 영향을 확인하기 위해 3차원 가상 시편을 제작하여 열해석을 수행하였으며, 이를 열평판법을 사용하여 측정한 열전도도 실험 결과와 비교하였다. 열해석 수행 시 그라파이트 재료가 지닌 열전도도 성능을 반영하기 위하여 해석 결과와 실험 결과를 기반으로 고체상의 열전도도를 역해석을 통해 계산하였으며, 그라파이트가 시편의 열전도도에 미치는 영향에 대해 분석하였다.

Keywords

Acknowledgement

본 연구는 한국전력공사의 2020년 선정 기초연구개발 과제 연구비에 의해 지원되었음(과제번호: R20XO03-04).

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