[stevehull]

Thumperoo,

I also love open loop (aka "pump and dump") and have one at my current home and farm. But city lots can't do that . . .

Yes, I agree that the thermodynamics of the open loop (almost constant inlet water temp) maximizes efficiency, but there are places where the water quality makes open loop applications VERY problematic.

In my opinion, we will look back in 30-50 years and grunt "uggh" when we think about burning oils to keep houses warm (just like today we look at homes with coal bunkers in the basement and the need to remove coal clinkers every other day from the burner). The vast majority of homes will be heated and cooled by GT heat pumps - which is really a solar application.

But to do that we need to have a way to more inexpensively couple the ground to the heat pump. That is where turbulence, equations and such are important to discuss.

Ohh, and I also use my outflow "pump and dump" water as a water source for watering my livestock. Keeps the water tubs cool in summer, warm in winter and never slimy. So I certainly DO like open loops! And the outflows from there fill a pond that I use for pasture irrigation.

Steve