Arf ... It's not as simple as Dedelco thinks! Until now, I did not want to attack too much the Canadian project (which goes in the right direction anyway) for lack of having better to offer and not harming the renewable sector, but here I let go ...
We must do an applied statistical analysis and establish a spatialization of the subsoil. Today we have these tools to do it, we might as well use them to avoid disappointments!
For purely illustrative purposes (and from memory)
At shallow depth, at least, if you want to make a sharp calculation (and these new technologies require it):
- take into account the possible slope of the land;
- take carrots to establish its compaction (see using a densitometer, if you don't have one you can tinker with a stake and measure the penetration by applying a weight, as with sandbags);
- see if there are “sheltered” surfaces and understand what is the heterogeneity and roughness of the surface (Raupach method);
- know its nature: know at what depth is "the horizon
clay ”, because rainwater easily percolates through
the sandy-silty horizon, which influences heat transfers, and consequently leads to high losses (there is hardly that at -30m where we have stable data);
- know the temperature curves, the local weather to establish its annual sunshine and therefore its energy potential in thermal solar;
- and also establish the cumulative annual water balance (including the seasonal components, the dominant hydrological processes by season);
- know the runoff (θsat and Zsable in autumn mainly, Dunne mechanism, etc.) since it will easily be understood that the natural dissipation will be accelerated by any effect of this type;
- know the retention and hydraulic conductivity curve for all the other seasons (Horton mechanism);
- evaluate the evaporation of the bare soil, the "summer transpiration", quite strong in the south;
etc ..
The problem is that there are several calculation methods! That it is necessary to take into account a curve which moves between diurnal period and night period, etc ... The job of the geological engineer is to choose the type of calculation best suited to the case ... I therefore definitely believe that 'we can't generalize anything! Say
ex abrupto that a solution would concern 95% of French people, as Dédé says, is totally abusive ... We can always copy and paste a formula gleaned from wikichose, it will only give you part of the problem ...
But we understand that it seeks to promote the storage of heat in the ground, in this sense it is very commendable. Only there are limits not to be exceeded ...
Then we can model and know what the ground can retain as heat ...
We cannot indeed afford an energy balance only under "potential conditions", and do that without knowing the efficiency of evaporation, "real" exfiltration of water, etc ... and say that it is the panacea, it is pipeau ...
Yes, alongside such approaches made seriously, and not with a slogan made on the back of the spoon as a dedication that touts the Canadian project, it's just good marketing ...