Not much activity in this part of the site lately but....curious if anyone has resources for calcs on friction loss (head loss) in geo loops with different fluids, and the velecities (Reynolds) and such? Frustratingly, I am in the engineering field and built a calc for this years ago and cannot find it. What I am working on is this....I already own a 5T ClimateMaster 2 stage unit. Will be using it in a 5800sf building but I will have supplemental floor heat if/when needed so not like we all die if things are not perfect. Mostly plan to run in the 1st stage (3T) mode. System is in KS and looking at 5 runs of pipe, down and back in a 1.5' trench, 5ft deep, trench 300ft long each trench, 5 trenches. That is 600ft per trench, 3000ft total. Can you throw variables at this deal? Yeah, probably until my ex returns, but the reality is I am on a large acreage, have equipment to do the job, and will plan to add to the system is things just don't run quite right, but I suspect this is pretty damn close. Thoughts.

This may work for you:

https://www.borstengineeringconstruction.com/Pipe___Pump_Design_Calculator__Darcy-Weisbach_.html

Be sure to read the associated directions.

We did 3' wide trenches about 7' deep. Keeping the pipes separated and further below the freeze line will help the late winter entering water temp.

Also used 1" pipe with a single pump, keeping the pressure drop low. Not sure of the reynolds number but not concerned because I have never seen my entering water temp below 36*F.

Using glycol, if you can use methanol it will flow better.

What are you using for the floor heat?

Floor is getting 2" of foam under it and radian pex that will be supplied by a waste oil burner. It will primarily serve as the "1st stage" of heating, and probably set the floor to 65 and let the Geothermal unit handle the rest. I will just have to figure out the balance between the two once its up and running.

I have heated floors with a geo water to water heater and a forced air geo and a natural gas hot water heater. I have done extended test and the natural gas water heater is 80 percent of the cost of geo to heat the house under the same conditions. Just a fyi.

Yeah, if I had natural gas here, things would be quite different! I intend to run hot water through the floor via some form of boiler. I was looking at wood but I can usually get waste oil about free and it is easier to modulate the heating. This should reduce the demand on the geo forced air unit and since my forced air will run off solar, I just want a little back up plan.

I also plan to do some sort of heat removal in Summer with the floor system. Not really "cool" the building but I think if I can use my well water to periodically run and remove some heat gain, it should help with the forced air demand. I do realize I cannot drop below dew point with cooling the floor so there will be some playing around with it.

I run my well through my floors in summer when I water the grass. All my floors are heated but mainly use the main floor (heat and cold go up and down so I don't run the down stairs that at all) I use a little tractor sprinkler and think that the huge flow of a sprinkler system wouldn't do as good of job cooling. With the low flow of this small sprinkler there still isn't that much temp change in the water. (3700sqft)

From an energy perspective I can run the sprinkler for 5 hours to one hour of running the geo. I do get condensation on the pipes in the lower storage area but non on the floor surfaces. I try to keep the humidity in the house at 50% year around.

My ecobee thermostats turn on and off the pumps for circulation and open a 24VAC ball valve for the sprinkler flow. I ran the sprinkler for cooling 81 days and 25 of those I turned on the geo this year. The year before I only ran the geo for 3 days. This was a constantly warm dry year in Michigan.