BRIEF RESEARCH REPORT article
Front. Phys.
Sec. Interdisciplinary Physics
Visualization of thermal interference effects in energy piles using transparent soil
Renrong Li 1
Yancheng Liu 1
Yang Zhou 2
1. Jiangsu Open University, Nanjing, China
2. Hohai University, Nanjing, China
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Abstract
Thermal interference between adjacent energy piles in group configurations can significantly reduce system efficiency. Conventional temperature monitoring methods rely on discrete sensors, which fail to capture the continuous spatial evolution of soil temperature fields. This study developed a non-contact visualization method for temperature fields based on transparent soil and digital image processing technology to investigate the thermal interference effects surrounding energy piles. The transparent soil was composed of fused quartz sand and a refractive index-matched pore fluid (mineral oil and dodecane at a mass ratio of 4:1). By calibrating the functional relationship between normalized pixel intensity and temperature, non-contact measurement of the soil temperature field was achieved. The temperature distributions under single pile and double pile conditions with different pile spacings (2 to 6 times pile diameter D) were investigated, and a thermal interference coefficient was introduced to quantify the thermal interaction between piles. The results indicate that when the pile spacing is within 4D, variations in spacing have a significant impact on the thermal interference effect. When the spacing increases to 6D, the thermal interference coefficient decreases to 2.5%. The proposed visualization technique successfully reveals the spatial pattern of thermal interference and provides quantitative references for energy pile group design. Limitations regarding scale effects, thermal property mismatch, cyclic loading, 3D heat transfer, calibration uncertainty, and groundwater advection are discussed to guide future research.
Summary
Keywords
Energy pile, Temperature field, Thermal interference, Transparent soil, visualization
Received
24 November 2025
Accepted
18 February 2026
Copyright
© 2026 Li, Liu and Zhou. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Yancheng Liu
Disclaimer
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.