12 Feet Under: 1000 Square Feet of Geothermal PC Cooling

[Romir]

Today's haul with a two foot long Lowe's receipt:



Not pictured are the 100' of 3/4" pvc pipes (plenty of extra) and 48' of the 3/8th wall insulation.

Pretty much everything except lengths of 3/4", 5/8", and 1/2" tubing has been purchased now. I'm still looking for a pressure gauge with a maximum reading lower than 100 psi. I also need some of the materials for the pump's sound dampened, and actively cooled housing. A small float switch that doesn't cost as much as the pump would be nice too.

Tomorrow I'll glue together the inside the house fittings and mount a scrap osb board to the utility closet's wall. The reservoir and filter are ready to be mounted. I might need to put the pump on a shelf above the floor to avoid a 90 degree connection to the temperature probe -> ball valve -> exit line through the floor. Leaving enough spacing so the tubing can flex upward should be the simplest way to handle that.

This is why I don't want to work outside tomorrow, even under the house. Friday isn't looking that nice either.



The $45 brazed heat exchanger with 1/2" barbs also arrived today. I can use it if I ever want to separate my pc loop from the geo one. Or it could be used to create a second cooled loop for other devices with only a slight reduction in the geo loops flow.





I almost bought one of those $10 pumps at harbor freight last night. It could pump water through a radiator stuck outside the window to cool one side of this heat exchanger. I also had to resist buying garden house adapters to do that with an open loop with the cold well water. If you can circulate colder water through one side like that, you can easily lower your loops temperature without impacting the too flow much or contaminating your pc's loop. I'd really like to get a Dwyer digital manometer to test the pressure drop, but looking at the flow reduction on the King meter will do for now. All the 1-wire pieces have already made a mockery of my budget.

There's nothing new to report on the shipping status of the R4 insulation foam and the 1-wire components. I only really need the moisture and temperature sensor before digging the geothermal trench. Most of the pipe insulation could be installed on the shallow trench's pipe with the buried coils in the ground. The next week and weekend are supposed to be dry and warmer so I hope they arrive.

[Vinas]

Where are you from, Romir?

Sounds like the project is coming along. Personally, when I go to lowes or HD it is always at least a $300 trip so I feel your pain!

[Romir]

Where are you from, Romir?

Sounds like the project is coming along. Personally, when I go to lowes or HD it is always at least a $300 trip so I feel your pain!

Tidewater Virginia. The visits have been a daily thing for the last week, and I'll need to go back for two more 33 cent T fittings tomorrow! I'm not going to use the pictured cross fitting because it points both temperature sensor wires away from each other. It'll be cleaner with the wires both going into the middle with two sets of Ts instead.

Today's update:

It's the calm before the storm. I'm now well and truly ready to put together the entire loop. Leak testing is on for this weekend!

Unfortunately the geothermal trench will have to wait for the thicker insulation and moisture sensor to arrive. An inexpensive 15 psi hydraulic pressure meter has also been ordered. Everything's coming together now. I'll call and check on the insulation's status tomorrow.

[nigelke]

thats insane i love it

[Romir]

thats insane i love it

The best is yet to come!


Today's update:

Not having any 45 degree angles kept me from finishing the crawl space plumbing today. The existing plumbing below the utility closet and the lack of crawl space the other way ruined my plan of only using one 90 degree angle.

That meant another trip to Lowe's tonight where I picked up a 10 pack and some more lengths of the 3/8th wall pipe insulation. I'm going to go ahead and use it for all of the pipes under the house. I just want to get it over with. 95% of the piping down there is AFTER the PC section of the loop so the ground should equalize the ambient gains or losses. It's also possible to add another layer of insulation down the road if necessary.

Working with one foot of clearance under the utility closet proved challenging with the power drill. With the screw its also about 1cm shorter than the space between the joists. My advice would be: use small tools, start at the hardest area first, and then work away from there.

That would've saved me time. Don't work in a open crawl space on a day with strong gusts either. Sand blasts to the face. :thumbsdow

I'm not sure how I'll bring in the 3 sensors wired to cat5e cables yet. I'd also like to wire a 24 port switch in the utility closet as well. So a more forward looking solution for many network cables would be nice.





The house section of the loop will be operational tomorrow. While leak testing I'll further coil the geothermal piping. Once that's done, I can connect it and check the flow with it above the ground. Seeing the flow rate loss upon adding a few spare waterblocks would be interesting if nothing else. They're going to add quite a bit of restriction to the estimated 4gpm flow.

The hobby boards 1-wire order will ship Monday, which means I'll have the ground moisture sensor mid-week. It'll probably read 100% all of the time so I'm considering tethering it to the bottom of a ten foot iron pipe that could be extracted later.

The excavator's current work project will also be finished mid-week. I'm feeling pessimistic on the chances of receiving the R4 pipe insulation next week though. It's getting more tempting by the day to spend more and source it elsewhere.

[shazza]

just sitting here in awe, Romir ...

[Devil_Dog]

I'm speachless......

Can't wait to see this.

[kgtiger]

Excellent work mate.

Keep up the hard work, I am sure it will all pay off big time in the end.

[Celestial Bliss]

Insane.

[Romir]

Today's update on the lack of said update:



The house loop is complete. I'm filling it up now.

[Naja002]

Looks Good! What's the max flow rate on that filter....?

[Romir]

Looks Good! What's the max flow rate on that filter....?

All I know is the label on it reads for use with 30-120 PSI. It's a Culligan whole house filter, but I use one under my sink without killing the flow.

When the pressure gauge arrives I'll hook it up with the King flow meter and test that filter with and without the element in it. I only bought it because I expected to spend $250 on the pump and not $100.

The pump uses 80-85 watts by the way. It also needs vibration dampening on the inlet and outlet connections. My osb board is lightly humming along with it. Looks like I'll really need to insulate the res to dampen it if nothing else!

[trn]

The Caterpillar 325 xtreme pc project tool.

[Naja002]

for use with 30-120 PSI.

Ok, well, that's the first problem: Unless I'm missing something....there's no way you are going to generate 30 psi.

As far as flow rate, that should mostly depend upon the filter that you put in it, so check before you buy. Some have flow rates of 10gpm which is fine. If it's a standard 10" housing and will accept standard 10" filters then it might be easier to get past that 30 psi...


Also, household water psi is normally around 40 psi....that's why it doesn't kill the flow.

[=[PULSAR]=]

This thread has really made me think about connecting a water loop to a homes internal hot water radiator system to heat the house during the winter. I wonder how many watts of heat I would need to be outputing.

[OldChap]

This belongs here

Still lovin' this thread, can't wait for the commissioning

[noeru]

I salute the work for you. And so we look forward to.
Please luck

[Romir]

Ok, well, that's the first problem: Unless I'm missing something....there's no way you are going to generate 30 psi.

As far as flow rate, that should mostly depend upon the filter that you put in it, so check before you buy. Some have flow rates of 10gpm which is fine. If it's a standard 10" housing and will accept standard 10" filters then it might be easier to get past that 30 psi...


Also, household water psi is normally around 40 psi....that's why it doesn't kill the flow.

Outside of reduced flow, why does the minimum pressure matter? I was confused last night when you asked about max flow because that hadn't crossed my mind with a 4.5gpm pump.

I'm running the temporarily bridged house loop with a 20 micron sediment filter at nearly 4gpm right now. 30 and 40 micron weren't available in stores.

The filter's outlet side ball valve will be inserted when I add the pressure gauge. Removing the filter casing right now would cause 6 inches of water from the res to drain through it.

Regarding the sink, there was still enough pressure like you mentioned, to max out of the 1.5 gpm aerator. The pressure loss from six feet of 1/4" tubing down there was what spooked me. It looks awfully funny going into a 3/4" filter.

[Naja002]

The minimum psi may be for the useful life of the cartridge.... As the cartridge clogs up it will take more and more pressure to force the water through it. It should be pretty irrelevant in your situation though: Filtering the initial water supply is a very good idea, but once it's well filtered...it should pretty much stay that way...it's a closed-loop. After you're all setup and the water has been well filtered....if things flow well then just leave everything be, or remove the filter. If you leave the filter and develop flow issues over time...the filter would be one of the first things to look at....

[Romir]

With all the dirt that blown around while working in the crawl space, I'm glad I had it. A dwyer digital manometer to accurately map the pressure drop of the various filters and empty casing would be nice about now. I'd love to know how much head losses I'll have with each individual block. It's getting more and more tempting to initially test with only the plate head exchanger though. EDIT: The original plan was to eventually remove the filter cartridge and use the empty space to hold silver. Adding the tube in the bottom of the res gave me a safe spot to do it there though.

Anyways....

The water temperature of the house section of the loop has equalized to 50f or exactly 10c. It was only slightly lower when I turned it on this morning, so the full effect of the 30f night didn't transfer to the thinly insulated crawl space piping.

I couldn't resist hooking up a heat source and seeing how much the temperature went up over time. An overclocked 5970 is the hottest thing I have until I make the 1500w heat stick.



That's all I felt comfortable recording for now because I don't trust with barbs with the waterblock's mini spacer in them. There are so few threads attached to the block.

The idle core temps were 10c and 12c. The load temperatures didn't rise over those few minutes.

I need to get the coils finished for above the ground chilling! It'll be colder on the ground than when its deeply buried. Until the sun comes out that is. It's supposed to be mostly sunny tomorrow so that's my best chance of making the coils easily.

Edit: The 10c water temperature is in the ballpark of what I'd have if the piping was buried and all finished. So those 5970 load results would be about the same. The same or better than my current idle results (20c/21c) in an 18c ambient.

[mit78]

its amazing,good temps,but its a expensive cooling solution!

[OldChap]

Did you think of running hot water into the pipe to make it easier to manipulate?

You mentioned having problems forming loops......You could coil the pipe (roll into a coil) then slide the coils to a half overlap (first pic) or pull further to extend the loops further (pic2)

[Romir]

its amazing,good temps,but its a expensive cooling solution!

Thanks! Yes it is, but I'm still on track for it to be cheaper than my current dual loop setup.

Did you think of running hot water into the pipe to make it easier to manipulate?

You mentioned having problems forming loops......You could coil the pipe (roll into a coil) then slide the coils to a half overlap (first pic) or pull further to extend the loops further (pic2)

That would be a quick way to supple it up. I feel like a traitor to the project by using the air route. I brought the the tubing in for the night so it warms up to at least 60f. It works for epoxies, putties, etc before heading into a cold garage or workshop.

I'm going to screw two 2x4s into a 4x8 sheet of osb tomorrow and get the coiling over with. It's supposed to be mostly sunny with a high of 54f. There's always the heat gun too...

50ish seconds in shows the board coil forming method

The house section of the loop seems leak free and I'm running everything through my (unplugged) pc's waterblocks too. RectorSeal seemed to fix the water forming on the EK gpu waterblock's mini-spacer.

[Romir]

You mentioned having problems forming loops......You could coil the pipe (roll into a coil) then slide the coils to a half overlap (first pic) or pull further to extend the loops further (pic2)

Sliding the coils down the line into the work area did the trick. Thanks.

Today's update:

Coiling the sun warmed pipe was quite easy. Once the first few loops are formed with the correct height, they can then be stood up vertically making further coils easy to size and secure. The coiled up slack piping can simply be "walked" down the line to the work area and quickly sized up then zip tied. When the slinky assembly got too cumbersome to support vertically , I moved it and rested it on the side of my house.

Slack coils down the line, the smaller the better. (Don't uncoil the piping like I did. Also when you do, remove the tie straps one by one. They're staggered so each strap frees a shorter length of the piping.)



A bit over 20 feet of 3.8 feet overlapped coils. I didn't need to make the overlap that tight but directly connecting the loops like that was fast and easy. Some of the far right coils need to be undone to run the return line back along the coils to meet up with the trench to the house.



It hasn't rained in days yet water has collected in the bottom of my supply/return trench. This ground is going to be WET.



My first knife screw up in over a decade. Pro-tip: use wire cutters to remove tie straps. Now to keep my left thumb clean and dry for a couple days. That's what I get for cutting towards myself, on the LAST strap.


So anyway, going down the hill and losing half of my piping to non-coil use wasn't part of the original plan. Visually seeing that has got me thinking.

If I could start over, I would've spent more on a 500 foot 1" coil and possibly used 1" PVC under the house. The head loss would've been lower resulting in more flow at a lower velocity. That would be extremely helpful for running a loop like this off weaker a pump or two. 18 feet of 1/2" ID PVC or 4 feet of 3/8" ID has the same friction loss as 500 feet of 1" ID pipe. 3/4" (garden hose size ID) is the sweet spot for flow, flexibility, and cost. This is why I didn't go with small refrigeration tubing.

On the other hand, pipe insulation for 1 inch ID piping isn't as commonly available. Something could be cheaply hacked together for a short supply/return line and if only coming directly up into one room. My 5/8th walled insulation hasn't shipped yet, probably in the next two days.

Right now I'm strongly considering buying a $30 100' coil of 3/4" black pe water piping and using it in the trench to the house. That's 100 more feet of cooling, a huge percentage increase.

I'd couple the loops near the surface so it could be checked up on or fixed if it developed a leak. With such low pressure in the loop I'm sure it'll be fine. Black PE water lines are pipes are coupled with barbs and clamps at pressures multiple times higher.

The Iwaki is now using 73w with my PC's three water blocks restricting it. I still have 10 feet of 7/16th tubing going to my PC, which is causing some unnecessary restriction. The filter will definitely be removed later too. I'm already further down the pump's curve than I want to be. Still no leaks.

[Frogeye]

too cool subscribed