Study of different grouting materials used in vertical geothermal closed-loop heat exchangers

R. Borinaga-Treviño, P. Pascual-Muñoz, D. Castro-Fresno, J.J. Del Coz-Díaz

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61 Citations (Scopus)
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As a renewable source, low-enthalpy geothermal energy is becoming more relevant in heating and cooling buildings, by using an adapted heat pump to exchange thermal energy with the ground. Vertical closed-loop geothermal systems exchange heat with the ground through a closed buried pipe system, sealed with a grouting material that ensures the stability and thermal transmission of the borehole. Different grouting materials have been tested recently, which use cement or bentonite as a base material. However, the use of recycled materials, which might contribute to the sustainability of the project, has not yet been studied. This paper analyzes the use of different natural and recycled aggregates as main constituents in cement-based mortars. Results show that all mixes fulfill the minimum consistency and strength requirements. The use of any of the aggregates proposed improves the thermal conductivity compared to the cement mortar on its own, independently of the proportion used. Limestone sand, silica sand and electric arc furnace slag enhance the thermal conductivity of the grout as its proportion of use increases. However, no satisfactory results have been obtained for Construction and Demolition Waste-based mixes because of their high water requirement.
Original languageEnglish
Pages (from-to)159-167
Number of pages9
JournalApplied Thermal Engineering
Issue number1
Early online date29 May 2012
Publication statusPublished - 10 Jan 2013
Externally publishedYes

Bibliographical note

NOTICE: this is the author’s version of a work that was accepted for publication in Applied Thermal Engineering. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Applied Thermal Engineering, 50:1, (2013)
DOI: 10.1016/j.applthermaleng.2012.05.029

© 2012, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International


  • Geothermal
  • Mortar
  • Grout
  • Conductivity
  • Recycled material


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