The Hole…Geothermal Loop…56K Warning!

[Naja002]

Months back, I was getting bored and looking for a project…a PC cooling type of project. I started seriously looking at putting copper pipe in a crawlspace and a number of other things. I ended up going with this seasonal dual car rad setup:

Yes, Another Car Radiator Thread....Major 56K Warning!

I ended up getting into “crunching” (Distributed computing) Boinc/WCG, F@H, GpuGrid, etc. Now I run 4 OCed rigs and 4 OCed Gpus 24/7. The entire setup sucks about 1,200-1,300 watts out of the wall. During the summer the heat is ridiculous—even with pumping a lot of the heat outside. It got bad enough that I purchased an 8K btu a/c right before the weather turned cold. Needless to say, my electric bill sky-rocketed. But now that system is providing my winter heat via the indoor rad…...I have not turned my heater on so far this year (temps as low as 30F/-1C with highs in the 50’s-60’s, but as low as the 40’s). The ONLY supplemental heat comes from a 1K watt $20 space heater from wally-world. When temps outside start dipping into the 30’s it’s in the low 70’s in here ( ~72F with 30-35F outside). Additionally, I don’t run it everyday and only run it a few hours through the coldest part of the night…some nights. Not much at all.

So, what does any of that have to do with “The Hole” ? Honestly, it’s just a little background to help you understand what’s going on here and how the goals have come about…..With the way the economy is and has been, things have reached a point where I would have to choose: Suffer, shutdown the PCs or do without heat. Now I don’t have to choose. My electric bill last summer kept climbing and climbing and climbing. With this seasonal car rad setup, my electric bill (after doing the math) decreased ~$40. That’s with a 20% rate increase. Its winter folks—everyone’s bills are going up. Mine went down! And its going to go down further. With this Geothermal Loop I expect to not have to choose this coming summer, and with the way things are looking atm….I’m not going to have to choose!


So, on with the show:

This is what I did, how I did it, why I did and what I would change—Yes, If I had it to do over….I would probably do it a bit differently:

First I had to decide what kind of pipe to use for the exchanger and why: PVC, HD polyethelyne, copper, etc. Then what size for maximum surface area v. cost and all that good stuff. Ultimately, I went with 3/8” copper refrigeration coils…50’ x 4 = 200’ total. And that is one part that I might change, if I had it to do over:






My original intent was to dig up an old plant bed, dig deeper and install it into there. But after thinking for a while, I came up with a number of reasons why I really didn’t want to do that. So, I sorted out a new location and started the hole from scratch:



8’ x 5’

Then the Real work began….sheesh, what a job:





By the end of the first day I reached ~22” depth. Now keep in mind that this is clay and got harder and harder the further down I went. Some of it was like trying to dig through concrete:

[Naja002]

So, bright and early the next morning, once again all wired-up on caffeine, I went back to work. I dug out about 25% of the next layer and decided to check something out. At ~22” depth I drove the shovel in, cracked the ground and inserted a temp probe….this is what I found:



Then at ~28” depth I did the same thing:



The increase in ground temp directly indicated to me that I may have reached temp stability. The frost line here is only 12-18” (less then 18”). Ground temp stability is reached shortly below the frost line….so, this makes sense.

Finally, after digging the hole I checked once again and several inches deeper….the temp was the same:



Understand that when I did these “tests” I just cracked the ground, inserted the probe as deeply as possible and got everything closed back up. Then waited for the temp to stabilize.

These tests indicate to me that I reached ground temp stability…at least for this time of year. Through out the winter this spot is shaded 24 hrs/day. In the summer it will get a few hours of sun, but not much. That’s one of the reasons that I chose this particular spot. As long as the temps don’t exceed ~68F….I expect to have almost free air-conditioning!!

So, by the time I got done digging the hole….this is what I had:





In the top left corner of the 1st pic above you can see where I dug out for the pass-thru into the crawlspace. That pass-thru is ~12” deep.



Just a pic of the final ground temp test and digging the pass-thru:





I had decided to put copper in the ground, but make the “run” with pvc. Part of the rationale of this was cost and part was thermal conductivity. Copper = ~401, PVC = ~0.19. I could have gotten picky about making the run to the hole out of copper (warmest water) and all that, but I decided to keep it simple, so I made everything out of pvc, except the heat exchanger in the ground (copper). Anyway, the hole and pass-thru where done, so now it was time to start the plumbing. Initially, I was going to do this a bit differently, but, ultimately, decided on what’s pictured below:

[Naja002]

As I’ve said in other posts….I like to build plumbing from opposite ends and from the middle to the ends….meet in the middle so-to-speak. Crazy? I don’t know, but that’s how I do it! So, I started at the pass-thru, but the first thing that I did was install a temp probe. I picked up this indoor/outdoor thermometer for ~$9 at lowes:



It has a 3m (10’) “outdoor” temp probe on it…..so, I threaded that through some ½” pvc as follows:



Got out the construction adhesive/caulk:



Pulled off the sticky paper and stuck it to the inside of the pipe:



Then filled the opening with caulk:



Glued the cap on (all of the pvc was glued together):



And let it sit for a bit:




Then covered it up:



I dug out an extra 2-3” at that spot in order to insert the temp probe. Heat rises. I want the temp of the ground…not necessarily “the pit”. Plus the end where it is buried is the cool end return. Hopefully it will work out as planned….it should, but we will see this summer.

After sitting buried for a bit this is the result:

[Naja002]

So, on with the rest of the plumbing. Again, starting in the middle. 1 ¼” pvc pipe was chosen for reduced frictional loss:









At this point I had pretty much decided to call it a day. But I had too much to do in too little time, so I went a bit further.

I decided to take the pit plumbing to the manifold start:






Took a soil sample in order to determine the soil’s pH. Got it setup for later testing:

Distilled water….









The liquid test bottomed out at 6.0 (as low as it goes). The Ph controller/probe settled at 5.9, so the soil is acidic. In order to help balance that out I picked up some Lime from lowes:



I put 2 cups at 1lb 11.5 oz each on the bottom of the hole:





I covered that with about 1” of soil to help prevent direct contact with the copper tubing:

[Naja002]

Finally, after deciding what size tubing, how much, etc….I had decided before even starting this hole that I would run 8 parallel loops = 8x 25’, so I had to measure out and cut the 4 coils in half:



So, now it was time to call it a day.

So, now on day 3 things were getting rough—really rough. Pumping caffeine and popping max strength Tylenols (heavy duty drugs here, folks ) it was tough to get started. But I knew that I needed to get this done and the hole filled back in. I had today and tomorrow to reach that point.

I picked up a container at wally-world to house the indoor/outdoor thermometer. Cut a small gap for the probe wire:







And stuffed this up in a spot that’s +12” above the ground. As a note: the ½” pvc also rises +12” above the ground.


Now, I realized before starting the hole that I would have to build the manifolds on site (in the ground). It would have been really nice to do it sitting in a chair, but that wasn’t going to be possible. The problem was the heat from sweating the copper and the copper’s connection to the pvc. So, prior to digging I sweated together the initial copper to 3/8” connections….all 16 of them:




So, I then sweated those onto each end of the 8 25’ coils, then sat down and applied Teflon tape to all, a 1 ¼” tee to 14 and an elbow to 2. Determined my pipe length for in between the fittings and cut 16 pieces of pipe. Glued those into one end of each and things were setup to be completed in the ground.

So, after setting everything up….it was time to get back into the hole and start putting things together. Ultimately, it ended up looking like this:







Now, for those who are going to say” Oh, man, you shoulda done this instead of that or that instead of this”….as I said at the beginning of this thread: If I had it to do over there are somethings that I might do differently. Don’t get me wrong…I am open to comments and criticism…there’s no problem there. But it is done the way that it’s done and initial results are very promising!

The hole actually has a grade. The sloping pvc is the input (warm water), the elbow straight up is the output (cool water). The grade slopes downward from the input ~29” to the output ~32-33”. The purpose for this is simply that heat rises. It’s a simple effort to help keep the warmer ground from affecting the cool water result. Also the tubing coils rise 3-4” above the ground…they are not in direct contact with each other as it may appear in the picture. When I filled the hole back in…I made an effort to make sure that I did not compress the coils onto each other. In other words, there is earth separating the coil loops. Yes, there is some contact, but not near as much as may be assumed from the pictures.

[Naja002]

So, after getting everything laid out, and with the repeated insistence of my Buddy Hicks ( Thanx, Bro!) it was time to leak test. I wasn’t going to, but I did. Running out of time I decided to hook up a garden hose, fill the system and then use it for the leak test:



Well, I had a leak. One of the 1 ¼” x ½” tees had cracked at the neck. I had this issue before on my seasonal manifold and fixed it like this (pix borrowed from that project):

Put gobs of pvc glue on/into the crack and squeeze it together with a clamp:







Again, those pix are from that project. Same issue, same fix….just more glue used on this problem.

So, after letting it sit for about an hour I decided to try the leak test again. The leak was down to a drip, no other leaks noticed and I knew it would be a few hours before the one leak completely sealed itself. So, still running out of time…I decided to move forward. I put a couple of inches of ground on top of the coils/pvc and then added another +3lbs of lime. Then kept filling in the hole. All-n-all I used probably 15-20lbs of lime adding some every 6” or so. I ran water the entire time to help the clay settle in and fill the gaps. I soaked everything down very well. I managed to get the hole ~50-60% filled and it was once again time to call it a day.

Day 4 was fairly simple. Finish filling in the hole, replacing the sod, spreading seed and just getting everything situated to where it didn’t look like I dug a hole (as much as possible anyway) and get everything shut down for a few days.

The Hole:



The Pile:



As day 4 went on I continued to try to fill/leak test everything. From what I could tell I still had a leak. Seemed to be about 111 oz/hour…just under a gallon an hour with only gravitational pressure. Hmmmm, not good, but 24 gals a day was something that I could live with and build a work around if I had to….but I’d rather not have a leak. Hmmmmm…..

So, everything was shut down in preparation for a few days at work. I managed to sort out what was needed in order to now complete the run inside to finish connecting everything into a working system. Stopped by lowes and got what I needed.

[teyber]

jesus, not much to say other then Awsome!

[xsbb]

OMG.. I'm impressed with your work!

AMAZING PROJECT!

[[XC] Hicks121]

Well done brother!!

How's the back feeling?

This will be great at the cottage.

[eligray]

WOW! Great setup! I'd definately use a high-flow pump on that if i were you, especially since you have so much dissipation. With all that dissipation, peltiers become a lot more viable. Did you use fine, powdered pepper to patch up your leak? Everything about this project was great. When you said at the top that you might have changed how much pipe you used, what specifically did you mean? Very nice!

[orclev]

You are a sick sick man, but in a good way. That's a seriously awesome setup. So yeah, now that we've seen your awesome work, what lessons did you learn from it, and what would you do different the second time?

[Unseen]

crazy people...

[Quad-Damage]

how loud is that setup

[Naja002]

jesus, not much to say other then Awsome!

Thanx!

OMG.. I'm impressed with your work!

AMAZING PROJECT!

Already looks like money well spent!

Well done brother!!

How's the back feeling?

This will be great at the cottage.

Bro, You won't regret it. Set it up at the cottage and the Mrs. will be begging you to set it up at home.

WOW! Great setup! I'd definately use a high-flow pump on that if i were you, especially since you have so much dissipation. With all that dissipation, peltiers become a lot more viable. Did you use fine, powdered pepper to patch up your leak? Everything about this project was great. When you said at the top that you might have changed how much pipe you used, what specifically did you mean? Very nice!

Thanx! The pump that I have on it now is an Eheim 1262, 80w, 11' 6" of head and 900gph. Its definitely strong enough for the job, but I may check it out with an Eheim 1250. The temporary pump that I used was a low end: ViaAqua 1800---6' head, 480gph, 28w. They are great little pumps for what I used them for, but I don't really trust them to hold up in this kind of application, but it did fine for the testing.

From what I've read 3gpM (180gpH) is the minimum in order to create "turbulant flow". Now I assume that's within the standard 1" pipe (usually HDPE). If so, then I am also willing to assume that it would take a bit less in the 3/8"OD pipe that I'm using and with the manifold entrances and exits, inertia changes as the water loops through the coils, etc. I would say that this 1262 can handle the job very nicely. It's definitely looking that way.

Anyway, There is no need for a large Iwaki type pump sucking 140-240w out of the wall. My intent/goal here is to gain the most benefit at the least electric cost. An Eheim 1250 offers 6'7" head, 28w, 320gpH. That may not be quite enough, but 2 of them (1 at each rad) would do the job and still only suck 56w. Basically, $4.06/month v. $5.80/month. Not really worth shelling out $200 for....

I used what pepper I have on hand. "Pure Ground Black Pepper" from wally-world. The refill type can. Worked great....so far! I may have to redo it periodically, but all things considered...it shouldn't take too many repeats to clog up the leak. Either way, at this point its not leaking, so life is Good.

You are a sick sick man, but in a good way. That's a seriously awesome setup. So yeah, now that we've seen your awesome work, what lessons did you learn from it, and what would you do different the second time?

Thanx! See below....

crazy people...

Trust me...I prefer Crazy over normal. Normal people don't enjoy their life as much as I do....

how loud is that setup

Hard to say really. I would guess that its about as loud as a 5K-8K window A/C when the compressor is on and the fan on high. Not dead silent, but not really obnoxious either. The biggest problem with this exact setup is the car rad fans....they have a slight whine to them. But I could redo things and use the 9" fans like I have on my outside rad...it would be a bit quieter, but suck a little more juice. The 4 80mm PC fans blowing into the bottom half of my setup are considerably louder. Here's a couple of pix so you understand what I talking about:





Plus I have 3x 120mm at the PCs and 3x 80mm.....Its not as loud as it seems--until everything gets shutdown....then I realize that its a mini airport in here.

Anyway, it's no where near as loud or obnoxious as it may sound in that video. I can turn my volume up and make the noise in that video sound like a 747 is taking off in here.

So, w/o the PC fans, etc.....just the car rad fans, psu and pump--its actually very quiet. The pump is silent...that's why I bought Eheim. The psu is very quiet, and the car rad fans are quiet, except for the slight whine...it's very slight, but its there. The PC fans set up the way they are do a good job, but they are considerably louder then the rad setup.

wow. impressive - from concept to execution. I'd rate that as xtreme. good job!

Thanx!


Ok, so what would I change? Hmmmmm, at this moment I'm not sure really.... Things seem to be looking very promising, but I won't know what the real deal is until this summer.

I would seriously consider going with straight pipe though. Not sure that I would, but I would definitely look into it. Cost v. surface area, etc. Would make it easier to build the manifold et al above ground prior to digging. A copper manifold would give a bit more exchange surface area.

So, all-n-all...right now....I'm not sure what I would change. I guess I'll just have to wait and see how things actually work out.

[Plan.B]

wow. impressive - from concept to execution. I'd rate that as xtreme. good job!

[shoopdawoopa]

You sir are extreme

[OldChap]

I remember the planning stages.........so good to see this come to fruition .....will be waiting for your summer temps.....This is a digg it for sure

[Naja002]

You sir are extreme

Thanx!

I remember the planning stages.........so good to see this come to fruition .....will be waiting for your summer temps.....This is a digg it for sure

Same here....on boths counts: Glad to have it done and waiting on summer performance....!

[[XC] gomeler]

That is an amazing project. I'm really interested in seeing the summer performance. I hope the system is able to dissipate all the heat you are dumping into it. Instead could you have used aluminum tubing? Shame to hear about the leak, hope the black pepper trick holds and doesn't impede performance too much. Keep us updated, I've always wanted to implement a system like this but never had a permanent house to do it at.

[HDCHOPPER]

glad to see you got it done exellent job man !!

[[XC] Hicks121]

So Naja, can I borrow your backhoe?

[npk]

Next time when the wife says I´m crazy, referring to the way I cool my rigs, I´ll show her this thread! now that´s what I call extreme cooling.

[Naja002]

That is an amazing project. I'm really interested in seeing the summer performance. I hope the system is able to dissipate all the heat you are dumping into it. Instead could you have used aluminum tubing? Shame to hear about the leak, hope the black pepper trick holds and doesn't impede performance too much. Keep us updated, I've always wanted to implement a system like this but never had a permanent house to do it at.

Me too. This current loop will definitely handle the PCs....that's not an issue at all. But I plan on using it for A/C cooling....however, I am also getting geo-setup for the PCs...see below. I expect the pepper to hold much better then in a car rad. I'm hoping it just becomes a paste and patches the leak. It won't impede performance. I flushed out the system before I finished running the plumbing, so pretty much all that's left is the pepper patch. Whenever you do get a permanent place...looking into geothermal would be a great idea!

glad to see you got it done exellent job man !!

Me too! Thanx!

So Naja, can I borrow your backhoe?

No, no, no and no. Well,.......ok.....wait a minute.....if there's a body involved then I'll help you out, but otherwise: No, uh-uh....too much like work. Wait, scratch that--it's nothing but work. I can ship you the bucket, but you'll have to work out the mechanics/hydraulics yourself.....

Next time when the wife says I´m crazy, referring to the way I cool my rigs, I´ll show her this thread! now that´s what I call extreme cooling.

Yes, always helps to look sane by pointing to the crazy people.....




Updates:

Managed to get the elbow installed in order to eliminate the creased tubing:



Turned out to be a real pita. Installing the elbow was no big deal, but I only have 1 set of drains atm, so trying to bleed the air back out of everything (both car rads, geo-loop, PCs, etc) was about a 3 hr job.



I've been trying to sort out how to set things up for this summer. Looking at buying a couple more car rads, trying to figure out placement, plumbing, etc.....just tossing ideas around in my head. Well, after playing around with this Geo-loop I know that it can handle the PCs with no problem, so I've decided to install another one....No, not the same as this last one. Basically I'm back where I started in May: Crawlspace......?

I stopped by Lowes last night and picked up 200' of the yellow pipe wrap insulation. I'm going to cover that with the black foam after I get the pipe wrapped. But while I was there....I picked up 90' of 1/2" straight type M copper pipe.

My plan is this: The air in the crawlspace stays about +/-60F during the warmer months. After I get the heat exchanger built I am going to drag it under there and dig the ground out ~2". Then install the exchanger and cover it up.

The current loop is ~19.6sq. ft. This next loop should be just over half of that at ~11.75 sq. ft. The PCs raise the air temp coming out of the car rad 7-9F, so I wouldn't expect it to increase more then double (14-18F) on a half-sized exchanger. The spot is shaded 24/7 and the air is also. There's some air-exchange of course, but it's not massive or anything. I think a shallow geo-loop will work out well. My plan is to use this next loop strictly for the PC cooling. It will eliminate the outside car rad and allow me to use that in the living room-- a nice, big triple-core rad.

$175 is what the stuff cost. By the time I purchased a car rad for the living room, another for the outside setup.....I would have spent over $175 for the rads, fittings, etc. So, I'm hoping/thinking/expecting this to not only be less expensive.....but I honestly think this will work better overall also.

After pondering the design for a while, I think that I am going to hit lowes and return a few pieces and get some others. I'll need to think on this for a bit. The cost is going to go up some, so I'll let ya'll know what the deal is after I get it sorted out completely.... Either way, another...PC dedicated loop...is on its way....

[Naja002]

Ok, made it back to lowes, so it's time to up-date some $$$-figures....

$527.15 is what I had figured for the initial loop. Now it's time to add the isulation wrap and foam:

Wrap: $16.34
Foam: $12.78

New total: $556.27



PC dedicated Loop:

After returning some goods and getting others the new total is: $175.45

I am not expecting to insulate this piping. I may need to, but if so....I really don't think it would be much. Mainly toward the outside where it comes up through the floor to the manifold in here.

So, expected total for both loops is currently: $731.72

That of course is not including pumps, rads, etc......

Adding in those bigger items--prices are shipped:

Outside triple-core rad--$130
Inside double-core rad--$68
Eheim 1262--$109
Mag 9.5--$79

New estimate: $1,117.72

I will be putting together the new loop today or tomorrow....not sure when installation will take place though, but I am eager to get it setup....



Also, I had purchased 90' of 1/2" copper pipe. I was going to do an 8x 10' loop and use the extra 10' for the manifold. That's been changed. The manifold is going to be pvc and I decided to return the extra 10' instead of incorporating it. So, the loop is still going to be 80' of copper, but that works out to 10.5 sq. ft. of copper surface area.

[Solarfall]

hhahahah DAMN!!! .. just stumbled into this thread.
that's pretty insane dude as in INSANELY AWESOME .. this is exactly why i love XS