Numerical modelling of geothermal piles in tropical environment: group effect on heat dissipation

Resumo

In tropical countries, geothermal piles are foundation elements that, besides providing structural support,
dissipate heat from the internal environment of buildings to the foundation soil. Since foundations are usually
composed of pile groups, the interactions among piles should be investigated also from the thermal efficiency
standpoint. This paper presents a numerical model of a 5-pile group to study the influence of number and position
of thermo-active piles on the heat transfer of the geothermal system. The numerical model was developed with
ANSYS FLUENT and was validated with results obtained by Almeida [1] in his numerical model for a single pile.
Results indicated that the thermal influence radius does not increase linearly with the number of thermo-active
piles and that, in the limit, a group of piles may thermally behave as single pile. This study showed the importance
of simulating heat transfer on pile groups for the improvement of geothermal foundations design, since the
activation of all piles may lessen the thermal performance of the group.