Browse > Article
http://dx.doi.org/10.7843/kgs.2010.26.7.93

Evaluation of Performance of Grouts and Pipe Sections for Closed-loop Vertical Ground Heat Exchanger by In-situ Thermal Response Test  

Lee, Chul-Ho (School of Civil, Environmental and Architectural. Engrg., Korea Univ.)
Park, Moon-Seo (School of Civil, Environmental and Architectural. Engrg., Korea Univ.)
Min, Sun-Hong (School of Civil, Environmental and Architectural. Engrg., Korea Univ.)
Choi, Hang-Seok (School of Civil, Environmental and Architectural. Engrg., Korea Univ.)
Sohn, Byong-Hu (Plant Research Division Building & Urban Research Department, KICT)
Publication Information
Journal of the Korean Geotechnical Society / v.26, no.7, 2010 , pp. 93-106 More about this Journal
Abstract
In performing a series of in-situ thermal response tests, the effective thermal conductivities of six vertical closed-loop ground heat exchangers were experimentally evaluated and compared one another, which were constructed in a test bed in Wonju. To compare thermal efficiency of the ground heat exchangers in field, the six boreholes were constructed with different construction conditions: grouting materials (cement vs. bentonite), different additives (silica sand vs. graphite) and the shape of pipe-sections (general U-loop type vs. 3 pipe-type). From the test results, it can be concluded that cement grouting has a higher effective thermal conductivity than bentonite grouting, and the efficiency of graphite better performs than silica sand as a thermally-enhancing addictive. In addition, a new 3 pipe-type heat exchanger provides less thermal interference between the inlet and outlet pipe than the conventional U-loop type heat exchanger, which results in superior thermal performance. Based on the results from the in-situ thermal response tests, a series of economic analyses have been made to show the applicability of the new addictives and 3 pipe-type heat exchanger.
Keywords
Addictive; Bentonite grout; Cementitious grout; Thermal conductivity; Thermal response test;
Citations & Related Records
Times Cited By KSCI : 4  (Citation Analysis)
연도 인용수 순위
1 이세균, 우정선, 김대기 (2008), "지중유효열전도율 해석에 사용되는 선형열원 모델의 초기제외시간 결정에 관한 연구", 에너지공학회 논문집, 제 17권 3호, pp.167-174.   과학기술학회마을
2 임효재, 정계훈, 한지원, 박경우 (2007), "국내의 주요 지역에서 밀폐형 열교환기의 열전도도 측정", 대한기계학회 2007 춘계학 술대회 초록집, pp.1363-1368.
3 손병후, 신현준, 안형준 (2005), "열응답 시험과 변수 평가 모델을 이용한 그라우트/토양 혼합층의 열전도도 산정", 대한설비공학회 논문집, 제 17권 2호, pp.173-182   과학기술학회마을
4 손병후, (2007), "그라우팅 재료가 지중 유효 열전도도에 미치는 영향", 대한기계학회 2007 춘계학술대회 강연 및 논문 초록집, pp.1333-1338.
5 Gaia Geothermal, LLC (2005), Ground Loop Design 5.0.
6 건설교통부 (1998), "귀래-매지간 도로확장 및 포장공사 토질조사보고서", 시추 주상도 (BB1-BB5), 국토관리청, 원주.
7 길후정, 이강자, 이철호, 최항석 (2009), "Numerical Evaluation on Thermal Performance and Sectional Efficiency of Closed-Loop Vertical Ground Heat Exchanger", 한국지반공학회 논문집, 제 25 권 3호, pp.57-64.
8 Paul, N. D. and Remund, C. P. (1997), "Physical, thermal and hydraulic properties of bentonite-based grouts", Electric Power Research Institute, Final Report No.TR109160, ERI Project RP38 81-1.
9 PCA (Portland Cement Association) (1997), "Portland Cement, Concrete and Heat of Hydration", Concrete Technology Today, Vol.18, No.2.
10 Carslaw, H. S. and Jaeger, J. C. (1959), Conduction of Heat in Solids, 2nd edition, Oxford Science Publications, pp.261-262.
11 Gehlin, S. (2002), Thermal Response Test (Method Development and Evaluation, Doctoral Thesis, Lulea Univ. of Tech.
12 Kavanaugh S. P. and Rafferty K. (1997), Ground-Source Heat Pumps : Design of geothermal systems for commercial and institutional buildings, ASHRAE.
13 IGSHPA and Oklahoma State University (2000), Closed-Loop /Ground-Source Heat Pump System : Design and Installation Standards 2000, Oklahoma State University, Stillwater Oklahoma.
14 Ingersoll, L. R. Zobel O. J. and Ingersoll A. C. (1954), Heat Conduction : with Engineering and Geological Applications, 2nd ed. McGraw-Hill, New York.
15 최항석, 이철호, 최효범, 우상백 (2008), "지중 열교환기용 뒤채움재의 물리적 특성 연구", 한국지반공학회 논문집, 제24권 1호, pp.37-49.   과학기술학회마을
16 정영만, 구경민, 황유진, 장세용, 이영호, 이동혁, 이재근 (2008), "지중열전도도 측정과 지중열교환기의 열확산 특성 분석", 대한설비공학회 논문집, 제 20권 11호, pp.739-745.   과학기술학회마을
17 지식경제부 (2008), "신.재생에너지설비의 지원.설치.관리에 관한 기준", 지식경제부고시 제2008 - 232호.