If WF has a hole in their dealer network in your area they should be willing to start a new dealer, though not one selling competitor's gear

That said, all the top brands have comparable quality - the competence and integrity of the installer makes or breaks the job (what Joe said)

Jumping back on topic, sort of, when the EWT approaches 32F it seems to settle there, at least for me, I haven't dropped below 33F yet.

My question is passing that 32F point in a ground loop is there much more energy out there as it passes the freezing point or does it not work the same with the ground? I know it takes 1 BTU to lower 1 pound of water 1F, but that freezing point take considerably more energy to drop from just above freezing to just below freezing, so would the ground be similar?

I would say yes in most cases unless the ground is bone dry. I see this effect pretty clearly in my loop (see attached). I believe the more advanced loop modeling programs account for this. If you don't account for it at least it gives you a safety factor in your loop design!

I don't think there's anything magical about 32 °F.

For a vertical loop:

I believe if your EWT is staying at any temperature, plus or minus a degree or so, this means the rate of heat you're removing from the earth is about the same as the nearby earth's ability to replenish the heat (move toward the pipe).

And the rate of heat you're removing from the earth will be dictated by the structure's heating need.  Which is probably most influenced by the weather.

So my guess is your weather at the moment is not at one extreme or another.  If it were to get suddenly much colder than usual and for an extended period of time, then I would expect your EWT to decline.  And visa versa if you suddenly have an extended heat wave.

For example, in the month of Feb., my EWT stayed around 65° all month.  And looking at the Feb. weather, it was, until the end, pretty much averaging about 53↑ each day.  And looking at my Heat of Extraction from the loop, it averaged 67 KBTU/day.  Now that the weather has gotten dramatically warmer, I'm seeing my EWT rising, as my need for heat from the earth as not nearly as much as the earth's ability to warm up near my pipes.

Parenthetically, noting a constant 65° EWT all month, and noting an average HE of 67 KTBU/day, it's reasonable to conclude that thermal transfer interface between the earth and my closed loop is at leat 67 KBTU/day.

For a horizontal loop:

I don't know if the above explanation is valid, since now the earth's temperature away from the pipe is also going up as the weather is getting warmer.  If your EWT is staying constant at the moment, perhaps your earth is going through the 'swing point' where it's shifting from getting colder to getting warmer.  And simultaneously, your weather pattern is holding relatively constant such that your HE is holding at some fixed amount per day.

Best regards,

Bill

It's not magic, just physics! :) I'm fairly certain I can show that my loop temp does stabilize near freezing - it is true that right now is about the turning point for ground temp at that depth, but given the unusually cold January we had my loop would have been well below freezing by the end of January. I'll have to think about how best to show this - I've threatened to before but never found the time. I'll try plotting the delta between the undisturbed ground temp and the loop temp along with heat extraction.

Brock,

Weren't you referring to the extra energy released when water freezes (phase change)?

Regards, Masoud

Right, our EWT is still slowly dropping and I am guessing it will until it starts to warm up and I reduce the heating needed. But that’s sort of what I was wondering about, was if I am pushing out 29F water and returning 33F water, is that just where I happen to be and will be given my heat extraction rate I am at right now, or am I pushing up against that point where the ground starts to physically freeze around the loop. I guess either way I am fine, more of a curious question.

Does anyone out there have a history with EWT's dropping below the 32F point?

Here is what ours looks like since we turned it on 47 weeks ago; the initial dip was heating up the 16,000 gallons from 40F to 90F.

At the risk of further flogging this dead horse, I would again point out that 32* is not a milestone here as it is the freezing point of water. Geo loops in my area have a brine that consists of antifreeze and water and are protected to 15-20 degrees.
We all know that higher EWT's offer more heating btu's and cop's, but we also must approach every design with all economies involved...loop cost, antifreeze cost, flow center cost and efficiency, operating cost, installation cost........
J

If water / moisture is available to be frozen then yes, 32 deg F has something to offer:

The latent heat of fusion for water (freezing liquid into solid ice) is 144 btu / lb. That's the same amount of heat needed to drop a pound of water by 144 degrees.

I would expect that a loop field that begins to freeze adjacent water to exhibit a stable EWT, likely at or a couple degrees below 32 while water near tubes freezes, and that this could persist for days or weeks, possibly until the end of heavy heating season.

I second Joe's statement that it is perfectly OK for an antifreeze-protected system to operate in that regime if such operation was accounted for in the design.

Joe, I wasn't trying to imply 32F was any point to shoot for. For those of us that live "up north", going below 32F isn't uncommon and that our systems are setup to handle it. I was outright told our system would likely get below freezing and he had some system running about 20F and running fine.

What I was getting as was exactly what engineer just pointed out and likely why my system is doing what it's doing right now. I would imagine if the ground were relatively dry it would be easier to pass the 32F point.

Again I am not implying a system shouldn't go below 32F. I am honestly impressed I didn't push ours below 32F with the winter we have had.

I just did another "test" of sorts on our system. When I was getting the 33F EWT I shut off the geo unit, but left one of the field circulation pumps on. After about 1 hour the temperature was sitting really close to 38F. So I am guessing this is the "real" ground temperature out there.

My point is even if the EWT was 30F the ground would likely be 3F to 5F above that anyway.

I suppose a 32 degree contract would be important if you were worried about kids daring each other to lick the entering pipe.
The leaving pipe is always available for shenanigans in any heat dominant climate though.

Sure, ask for the guarantee. if you get it, I will guarantee you that your loop will be oversized by one to two toons - maybe more. You'll gain a wee bit of efficiency but probably pay an extra $2-6K for your loop field.

Satisfaction guaranteed or I will gladly refund your payment to me. *wink*