Large-scale subsurface seasonal heat storage for future value

I too extend my welcome. And, I extend thanks to the NSF for the support of this research at the Univ. of Utah. The concept of storing heat in the ground is certainly not new. Many, many cases have investigated heat to be stored underground. Getting the heat underground is somewhat of a problem, but the bigger issue is getting back that heat that has been put underground. It's really not "stored" if one can't recover the heat.