Geothermal Piles - Geotechnical Considerations

[twestpro]

I have a project in which the owner would like to use geothermal heating and cooling for the building. Due to the limited space on site and soil conditions they are going with a raft foundation and will install the geothermal loops within the building footprint. My question is what effect will the heating and cooling have on the soil properities and hence the bearing capacity?

 

[fattdad]

I'm going with zero.

f-d

¡papá gordo ain’t no madre flaca!

 

[MiketheEngineer]

I am going with zero UNTIL you have a leak!!!!

 

[Grouser]

How will the owner access the heating/cooling system for preventive maintenance or repairs? I'll bet sunny/shady side temperature differentials will cause more stress than the HVAC effects unless there are geothermal temperatures close to the system.
Cheers

 

[aeoliantexan]

I doubt that the geothermal system will affect the foundation noticeably unless the soil is highly expansive. If so, raising the temperature of the soil could result in shrinkage and settlement.

If the building is wide compared to the depth of the boreholes, or if a horizontal system is planned, the presence of the building may tend to trap the transferred heat below the building. Such a system depends on the ability of the ground to radiate and/or exchange heat with the air to remain near the average annual temperature. Putting it under the building may cause the temperature of the surrounding ground to rise or fall (depending on whether your heating season or cooling season is the greatest demand)and reduce the efficiency of the system.

Better consult an expert.