Wow, an underground sprinkler system for heat exchanger that's even deeper down!
The idea of being able to pump heat into the ground all summer (while using the cooling mode),
and have that heat stored there in a mass of nice moist soil, until you need it during the winter..
Is pretty danged cool!
Keeping your subterranean heat storage area wet, without exposing your
precious rain water to the ravages of the sun on the surface is very smart!
This scheme seems like it's going to work much better than just dropping
the water on the surface of a lawn area.
The only drawback I can see with a system like this, would occur if there
was flowing ground water, which took away the heat before it could be
extracted during cold weather..
But, that flowing water would still be at 60-65 deg F (around here), which
is still not bad for extracting heat or pumping some in..
With no ground water, the only worry I would have is, over-heating the
storage so much, that your heat pump couldn't squeeze any more heat into it.
That would make it impossible to use the cooling mode.. Maybe during
a 100 deg August..?.
Keep on Innovating !!
Cheers,
Rich