Geothermal Antifreeze Well Design

[Loumolito]

Where do you account for the antifreeze losses in GSHPCalc software?

If you have a 300 ton system load you need 300+ tons of cooling due to the antifreeze i.e. more wells required.

Or should I try to get my load calc program to account for the additional antifreeze load?

 

[Ziggypump]

I've never worked with the GSHPCalc spreadsheet before, I'm assuming you got it from the Geokiss website. But I have used GLD - Geothermal Loop Design - and there is a tab to include the water mixture.

Now, 300 tons of cooling is 300 tons of cooling. If your system is designed for 300 tons, making the well field large enough for 350 tons will not help anything. The glycol solution will effect the heat transfer properties of the fluid. This is why lower concentrations of glycol are desired. I've never seen a need for concentration higher than 30% propylene, and 25% propylene works well enough.

You want the program to take into account the heat transfer properties of the fluid. Get the program to take the glycol(?) into account.

 

[MissHVAC]

I also have not specifically worked with the GSHPCalc program, however...

Because antifreeze (some sort of glycol) mixed with water has different properties than water alone, this changes some calculations. For example, the total pressure loss across given well will increase if glycol is present, and therefore you may need to reduce the length of individual wells to get the pressure drop in an appropriate range, and thus increase the number of total wells. Also, you may need to reduce the bore length and increase the number of wells if you have wells that are significantly deep, where hydrostatic pressure on your pipe becomes and issue. Glycol present in the water will affect that.

Glycol does change the heat transfer properties of the fluid, and I'm certain that your program has a way to adjust that. I would suggest looking in the help file?