Well, the concrete insulates (it takes 1 meter compared to 1cm of PU ...?)
First of all, a big thank you for all these calculations.
For the “concrete”, it is me who suggested it, it supports as long as there is no reinforcement, if I do not say too blunders, it is the coefficient of expansion differentiated between the metal reinforcements and concrete - which is not the same and which is harmful (by causing the concrete to crack like during a fire for example, then causing the slabs to lose their bearing capacity), although my suggestion remains hypothetical, there the concrete would have no reinforcement (therefore no harmful Δ °) and it would not be load-bearing. The “only” major technical problem seems to me to be the location of the interchange. Because the pipes, for their part, were made of metal and therefore could not be embedded in a “concrete” at a desired isothermal temperature of 950 ° max. It is therefore necessary to provide a buffer zone.
As for the “service temperature”, it may be less than 500 ° C (Carnot cycle), which gives an idea of the admissible stresses for the buffer zone.
The rest is plumbing ...
In any case, this system will be useful, because with renewable energies, what we need are STEPs and this concept gives us them ... If this system makes it possible to overcome peaks in consumption (and it can do so) then the problem of the “load factor” of the network seems to me to be solved. If he does what he promises, so much the better!
STEP
