IDEAS home Printed from https://ideas.repec.org/a/eee/renene/v242y2025ics0960148125001107.html
   My bibliography  Save this article

Enhanced heat extraction for coaxial medium-deep borehole heat exchangers by adding triangular fins on the outer tube wall

Author

Listed:
  • Wang, Meijie
  • Wang, Jiali

Abstract

This study investigates the thermal performance of coaxial medium-deep borehole heat exchangers (CMDBHEs) with triangular fins added to the outer tube wall. The investigation is performed using ANSYS Fluent simulations. The results indicate that the outlet temperature and heat extraction rate increase with longer fins, more fins, and higher soil thermal conductivity but decrease with higher thermal conductivity of the inner pipe and grout cement. The relative improvement in heat extraction achieved by adding fins diminishes as borehole depth increases. After 120 days of continuous operation, heat extraction for a CMDBHE with 32 fins and a depth of 2000 m increases by 6.74 %–18.46 % compared to systems without fins. In cases where thermal conductivity increases with depth, layered models yield higher heat extraction than homogeneous models. However, when thermal conductivity fluctuates or remains uniform, both models yield nearly identical results. Over 25 days, under varying run-to-stop ratios, finned CMDBHEs achieve 11.46 %–13.87 % higher heat extraction rates. Combining fins with intermittent operation and improved inner-pipe insulation enhances heat extraction per unit runtime by 25.61 %–74.92 %. Additionally, adding fins to the lower section of the borehole pipe is more cost-effective than finning the entire length.

Suggested Citation

  • Wang, Meijie & Wang, Jiali, 2025. "Enhanced heat extraction for coaxial medium-deep borehole heat exchangers by adding triangular fins on the outer tube wall," Renewable Energy, Elsevier, vol. 242(C).
  • Handle: RePEc:eee:renene:v:242:y:2025:i:c:s0960148125001107
    DOI: 10.1016/j.renene.2025.122448
    as

    Download full text from publisher

    File URL: http://www.sciencedirect.com/science/article/pii/S0960148125001107
    Download Restriction: Full text for ScienceDirect subscribers only

    File URL: https://libkey.io/10.1016/j.renene.2025.122448?utm_source=ideas
    LibKey link: if access is restricted and if your library uses this service, LibKey will redirect you to where you can use your library subscription to access this item
    ---><---

    As the access to this document is restricted, you may want to search for a different version of it.

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:eee:renene:v:242:y:2025:i:c:s0960148125001107. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    We have no bibliographic references for this item. You can help adding them by using this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: Catherine Liu (email available below). General contact details of provider: http://www.journals.elsevier.com/renewable-energy .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.