Applicability evaluation of cast-in-place energy piles based on two-year heating and cooling operation

Sangwoo Park, Seokjae Lee, Chihun Sung, Hangseok Choi

    Research output: Contribution to journalArticlepeer-review

    11 Citations (Scopus)

    Abstract

    An energy pile is a type of ground heat exchanger (GHEX) that can reduce the initial construction cost by being installed in the existing foundation structure (i.e., pile). However, despite economic benefits, energy piles have not been globally employed owing to a lack of construction cases and appropriate design methods. Therefore, in this study, a design method applicable to large-diameter cast-in-place energy piles was developed and verified by conducting long-term monitoring on the heating and cooling operation. In addition, to evaluate the applicability of the cast-in-place energy piles, their thermo-mechanical behaviors and economic feasibility were analyzed using the long-term monitoring results. Although degradation of thermal performance and significant changes in the ground temperature were observed in the heating operation, it was concluded that the proposed design method could provide reliable design outcomes. The maximum thermal stress was estimated to be 2.38 MPa during the long-term monitoring, which is approximately 8.5% of the design strength criterion for cast-in-place concrete. Finally, compared with a conventional closed-loop vertical GHEX, the cast-in-place energy piles could reduce the initial investment cost by 25.31%, and the investment payback period was evaluated to be 1.61 years.

    Original languageEnglish
    Article number110906
    JournalRenewable and Sustainable Energy Reviews
    Volume143
    DOIs
    Publication statusPublished - 2021 Jun

    Bibliographical note

    Funding Information:
    This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science and ICT, MSIT) (grant number 2019R1A2C2086647).

    Publisher Copyright:
    © 2021 Elsevier Ltd

    Keywords

    • Cast-in-place energy pile
    • Ground heat exchanger
    • Ground source heat pump system
    • Long-term monitoring
    • Thermo-mechanical behavior

    ASJC Scopus subject areas

    • Renewable Energy, Sustainability and the Environment

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