pond.

[mstrblstr3]

This new design was developed to increase ground contact and decrease excavation invasions. Shorter tranches and less yard to fix. It is a mat that is about 4 ft tall and 45 foot long and when put in a pond it will produce 4 ton of heat exchange. The really cool application for it is being able to use a trencher instead of a backhoe for horizontal looping
Like i said before though, it is for quick installations of a geo water heater and pond loops officially. The horizontal looping for forced air applications isn't official yet but the field trials have all come back very positive.

[quailtrail]

I have a 4 ton geothermal unit using a plate coil in a lake that is 15' deep where the coil is. During the summer the water temp at 15' is about 98 degrees F which cuts the cooling SEER to about 16. You might want to check the temp in your lake before going this route.