Counterbalancing Ambient Interference on Thermal Conductivity Tests for Energy Piles


Thermal conductivity tests on Energy Piles suffer from ambient interference on the recorded fluid temperatures. Such interference is observed as sudden fluid temperature increases or stabilizations which require advanced data processing techniques for reliable estimates of the effective ground thermal conductivity. This paper presents a modified testing procedure to eliminate the ambient interference observed in thermal conductivity tests for short ground heat exchangers including Energy Piles. The proposed testing technique relies on counterbalancing the ambient interference when heating the circulating fluid. Supported with a full-scale field experiment on an Energy Pile, the proposed testing technique showed a successful elimination of the ambient interference and an accurate estimate of the ground thermal conductivity using the simple infinite line source (ILS) model. Further, the estimated ground thermal conductivity is independent of the number of hours included in the data processing which offers the potential to reduce the testing duration and consequently the associated testing costs.


Civil, Architectural and Environmental Engineering


The authors appreciate the support from the National Science Foundation under Grants CMMI-0928807 and CMMI-1100752 .

Keywords and Phrases

Ambient Interaction; Energy Pile; Geothermal Heat Exchanger; Thermal Conductivity Test; Thermal Response

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Article - Journal

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© 2015 Elsevier Ltd, All rights reserved.

Publication Date

01 Jul 2015