Concrete, Thermal Mass, and Stable Ground Temps – GreenBuildingAdvisor

I’m deeply curious if there’s a calculator or theory of calculation that can determine the regulating impact of concrete walls (x” thick) that are connected to footings of a given depth.

I’m working on an ICF house that is the following exterior -> interior.

Black brick facade -> 2″ gap -> 2.5″ EPS -> 8″-10″ concrete -> 2.5″ EPS -> Drywall

What doesn’t seem to be accounted for in any of the discussions of R-Value and ICF is the impact that connection to regulating ground temperatures has on efficiency of the wall system.

In the summer, as heat attempts to get from the outside (100 degrees, say) to the inside of the wall system, it will be slowed by the air gap, and then the 2.5″ of EPS. I’m curious if an ICF wall connected to footings that are 24″ below ground level will experience a cooling effect as heat passing into the wall attempts to find equilibrium with the cooler temps below, similar to how a geothermal system works. And vice versa in winter.

Or I could be completely out of my mind.

Any thoughts on how a mass of concrete running underground would impact the temperature of the wall and thus the movement of heat/cold to the interior?