I've been idly wondering about the public heated pools of late (looking at the iceblock in my back yard) and how they keep that solid 24º or whatever it is year round.
My understanding is that they've drilled into the artesian basin nice and deep, have run two pipes into the hole and are pretty much using a convection loop with a heat exchanger up top to heat the pool.
So, I'm curious. Technically, what's involved - firstly, why don't we see it in backyard pools? And why aren't we rocking big, fat versions with entrained turbines for power generation?