par Erol, Selcuk 
;Francois, Bertrand
Référence Coupled Phenomena in Environmental Geotechnics: From theoretical and experimental research to practical applications, CRC Press, page (491-499)
Publication Publié, 2013-01
;Francois, Bertrand Référence Coupled Phenomena in Environmental Geotechnics: From theoretical and experimental research to practical applications, CRC Press, page (491-499)
Publication Publié, 2013-01
Partie d'ouvrage collectif
| Résumé : | Experimental, numerical and analytical studies are carried out to enhance the thermal performance of vertical ground source heat pump (GSHP) systems by improving the grouting material with the addition of graphite powder. Several mechanical and thermo-physical tests are performed for two different widely used commercial grouting materials (i.e. bentonite-based and silica sand-based) and homemade admixtures enhanced with natural flake graphite, synthetic graphite and expanded graphite. Experimentally to assess the specific heat exchange rates, the prepared borehole heat exchanger (BHE) probes are operated using two heat pumps in a 1×1×1m3 sandbox under dry (solid - air) condition. The home-made admixture prepared with 5% natural flake graphite can be considered as an appropriate grout material for BHEs regarding to its rheological and thermo-physical properties as well as its cost. During the operations, the monitored temperature measurements in the sandbox are in agreement with numerical simulation and analytical approach prediction. The sandbox study shows that if the thermo-physical properties of ground is considerably low, the thermal conductivity of grout has no significant impact on the performance of BHE, the main resisting component in the thermal transfert being the ground itself. |
