Study on Thermal Behavior and Design Method for Coil-type PHC Energy Pile

Park, Sangwoo; Sohn, Jeong-Rak; Park, Yong-Boo; Ryu, Hyung-kyou; Choi, Hangseok

doi:10.7843/kgs.2013.29.8.37

Cited by 3 publications

(2 citation statements)

References 8 publications

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“…) 및 에너지파일 (Brandl, 2006;Laloui et al, 2003;2006;Bourne-Webb et al, 2009) (Morino and Oka, 1994;Li et al, 2006;Hamada et al, 2007;Nagano, 2007;Jalaluddin et al, 2011) (Gao et al, 2008;Jun et al, 2009;Wood et al, 2009)가 다수 수행되고 있으며, 실제 대규모 공공건물에 적용한 사례도 보고되고 있다 (Sekine, K. et al, 2007;Pahud and Hubbuck, 2007;Nam et al, 2007). 반면에 국내에서는 에너지파일의 연구 및 시공사례 (Park, et al, 2007;Yu, 2008;Lee et al, 2010;Park, et al, 2013…”

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“…또한 선형 열원 모델은 열원을 무한 선형으로 가정하므로 에너지파일, 에너지 텍스타일(energy textile), 스탠딩 컬럼 웰(standing column well, SCW) 등 다양한 형태의 지중열교환기에 직접 적용하기에는 한계 가 있다. 에너지파일의 경우에는 원통형 열원 모델(cylinder source model, Ingersoll, 1954), 개선된 일체 원통형 열원 모델(modified solid cylinder source model, Man et al, 2010), 링-코일 열원 모델(ring-coil source model, Cui et al, 2011) 등 선형 열원 모델의 가정 조건을 개선한 모델들이 개발되었으나, 신뢰성 검증이 충분하지 않고 모델 적용이 어려워 실무적으로는 사용되지 않고 있는 실정이다(Park et al, 2013).…”

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Evaluation of Heat Exchange Efficiency and Applicability for Parallel U-type Cast-in-place Energy Pile

Park¹

2015

Journal of the Korean Society of Civil Engineers

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An energy pile is one of the novel ground heat exchangers (GHEX's) that is a economical alternative to the conventional closed-loop vertical GHEX. The combined system of both a structural foundation and a GHEX contains a heat exchange pipe inside the pile foundation and allows a working fluid circulating through the pipe, inducing heat exchange with the ground formation. In this paper, a group of energy piles equipped with parallel U-type (5, 8 and 10 pairs) heat exchange pipes was constructed in a test-bed by fabricating in large-diameter cast-in-place concrete piles. In addition, a closed-loop vertical GHEX with 30m depth was constructed nearby to conduct in-situ thermal response tests (TRTs) and to compare with the thermal performance of the cast-in-place energy piles. A series of thermal performance tests was carried out with application of an artificial cooling and heating load to evaluate the heat exchange rate of energy piles. The applicability of cast-in-place energy piles was evaluated by comparing the relative heat exchange efficiency and heat exchange rate with preceding studies. Finally, it is concluded that the cast-in-place energy piles constructed in the test-bed demonstrate effective and stable thermal performance compared with the other types of GHEX.

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Evaluation of Heat Exchange Efficiency and Applicability for Parallel U-type Cast-in-place Energy Pile

Park¹

2015

Journal of the Korean Society of Civil Engineers

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Evaluation of Thermal Response Test of Energy Pile

Yoon¹,

Lee²,

Kim³

et al. 2014

Journal of the Korean Geotechnical Society

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Use of geothermal energy has been increased for its economical application and environmentally friendly utilization.Particularly, for energy piles, a spiral coil type ground heat exchanger (GHE) is more preferred than line type GHEs such as U and W shaped GHEs. A PHC energy pile with spiral coil type GHE was installed in an area of partially saturated dredged soil deposit, and a thermal response test (TRT) was conducted for 240 hours under a continuous operation condition. Besides, remolded soil samples from different layers were collected in the field, and soil specimens were reconstructed according to the field ground condition. Non-steady state probe methods were conducted in the lab, and ground thermal conductivity and thermal diffusivity were measured for the different soil layers. An equivalent ground thermal conductivity was calculated from the lab test results and it was compared with the field TRT result. The difference was less than 5%, which advocates the use of an equivalent ground thermal conductivity for the multi-layered ground.Furthermore, this paper also represents an equivalent ground thermal diffusivity evaluation method which is another very important design parameter.

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Evaluation on Thermal Performance Along with Constructability and Economic Feasibility of Large-diameter Cast-in-place Energy Pile

Park¹,

Sung²,

Lee³

et al. 2015

Journal of the Korean Geotechnical Society

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An energy pile is a novel type of ground heat exchangers (GHEX's) which sets up heat exchange pipes inside a pile foundation, and allows to circulate a working fluid through the pipe for exchanging thermal energy with the surrounding ground stratum. Using existing foundation structure, the energy pile can function not only as a structural foundation but also as a GHEX. In this paper, six full-scale energy piles were constructed in a test bed with various configurations of the heat exchange pipe inside large-diameter cast-in-place piles, that is, three parallel U-type heat exchangers (5, 8 and 10 pairs), two coil type heat exchangers (with a 500 mm and 200 mm pitch), and one S-type heat exchanger. During constructing the energy piles, the constructability of each energy pile was evaluated with consideration of the installation time, the number of workers and any difficulty for installing. In order to evaluate the thermal performance of energy piles, the thermal performance tests were carried out by applying intermittent (8 hours operating-16 hours pause) artificial cooling operation to simulate a cooling load for commercial buildings. Through the thermal performance tests, the heat exchange rates of the six energy piles were evaluated in terms of the heat exchange amount normalized with the length of energy pile and/or the length of heat exchange pipe. Finally, the economic feasibility of energy pile was evaluated according to the various types of heat exchange pipe by calculating demanded expenses per 1 W/m based on the thermal performance test results along with the market value of heat exchange pipes and labor cost.

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Study on Thermal Behavior and Design Method for Coil-type PHC Energy Pile

Cited by 3 publications

References 8 publications

Evaluation of Heat Exchange Efficiency and Applicability for Parallel U-type Cast-in-place Energy Pile

Evaluation of Heat Exchange Efficiency and Applicability for Parallel U-type Cast-in-place Energy Pile

Evaluation of Thermal Response Test of Energy Pile

Evaluation on Thermal Performance Along with Constructability and Economic Feasibility of Large-diameter Cast-in-place Energy Pile

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