[stevehull]

AC is correct, but sadly much of the flow in vertical and horizontal ground loops is laminar and not turbulent. Straight pipes have the highest laminar flow conditions, curled slinky just a bit below that.

But imagine if the ground loops could be induced to have a large amount of turbulent flow. It would cut off almost 50% or more of the necessary pipe length.

I have been working with the OSU team on injecting air bubbles into the loop so that the water going down the loop is maintained as a waterfall (clearly turbulent). The return has a vent on top that has a vent to remove the air.

Then we are also using a proprietary fluid additive that makes the fluid far more slippery and less viscous than water. This also promotes turbulence.

We are also working with a company to put spirals on the inside of the HDPE pipe to spin the water (think rifling in a gun barrel) and also spot divots inside the ground loops thereby minimizing laminar flow conditions and also creating turbulence around the many divots.

The extrusion process with inside spirals and divots is tough, but it has HUGE rewards.

We have also found that 1 inch tubing is far better than 3/4 inch HDPE if you can minimize laminar flow. The cost of pumping is higher with turbulent flow, but that is small stuff.

The goal is to reduce the length of the ground loop by 50% or more with minimal cost. A classical engineering problem . . . .

Steve