Geothermal Ground Loop Collector

selfdiy

Hi all,
Just wondering what fluid you use in your Ground Loop Collector.

I think mine has methanol in it, I'd like to get it checked, to see is it still at full strength.

Anybody know of somebody that can check this or even know how to check it?

Many Thanks, in advance.

KAGY

selfdiy wrote: »

Hi all,
Just wondering what fluid you use in your Ground Loop Collector.

I think mine has methanol in it, I'd like to get it checked, to see is it still at full strength.

Anybody know of somebody that can check this or even know how to check it?

Many Thanks, in advance.

Seriously doubt it's methanol, it's more than likely propylene glycol or ethylene glycol (antifreeze) in water. Unless you've been topping up with with lots of water it won't have degraded.
To check it you'll need a hydrometer (or specific gravity meter). You could also weigh a known volume to get its density. Check your op manual for the recommended range, or find charts on the web.

selfdiy

Thanks Kagy,
Its definitely methanol. The collector had a leak that I had to fix, so lost a certain amount of fluid.

With your advice I know what instrument I need to get to check it.
Now I just need to find some charts with the correct values and if I need to top it up find someone todo that.

Greenlight

I've seen a good few IVT and Hautec Heat Pumps with Methanol instead of ethlene glycol. If you haven't lost that much fluid and it was only a leak then you should not have too much of an issue. If it's a hoziontal collector then you may have 600 to 900 liters of brine fluid in your collector. A leak of 10 to 20 liters won't affect your freeze point too greatly. As long as you don't have any air in your system and you have about 0.5 to 1.0 bar pessure then i reckon you will ok to run without topping it up with more methonal.

Depending on the model of your heat pump, if you do have an insufficient freeze point in your brine then you'll see Low Brine alarms, where the sesnor on the bine out side of the evapourator drops below an allowable set point (normally about -8 degrees, again depeding on your heat pump make)

You could always take a sample of your brine and out in your fridge freezer and see what temp it freezes at. Save you buying any refractometer etc.

Hope this helps

selfdiy

Thanks GreenLight,
You have a good point. I guess if the level was too low the machine would show up a fault code.

Just out of curiosity is there a point in which the dilution becomes more or less efficient in terms of heat transfer

KAGY

selfdiy wrote: »

Thanks Kagy,
Its definitely methanol. The collector had a leak that I had to fix, so lost a certain amount of fluid.

With your advice I know what instrument I need to get to check it.
Now I just need to find some charts with the correct values and if I need to top it up find someone todo that.

I stand corrected, haven't been following the tech since I got mine in 7? years ago. Maybe http://www.methanol.org/Technical-Information.aspx might help.
But as green light says if it doesn't freeze at -18 in your freezer you'll be ok

selfdiy

That is a good test, i'll be changing a part during the week, so I can collect a sample then and try the freezer test.. if it survives that I'll be more then convinced:)