DIY geothermal chiller

shyland83

shyland83

New member
So ever since I saw daves pvc design a while back I have been thinking about making a geothermal chiller. I have been reading on the DIY forum and I decided i'm gonna go for it.

So heres my plan. Please chime in with any suggestions or opinions. My tank is in the basement. So in the workshop area behind the tank i'm going to bust a hole in the concrete. The basement seems like the perfect place to do this not only because it's closer, but because I don't have to dig down far to get cool sand and it should be very damp which is good for heat sink. If i hit water, even better.

Then dig a hole with a post hole digger and bury a coil of 3/8" copper tubing and backfill the hole. I will then bend up 10ft of 3/8" titanium tubing into a coil and put it in the sump. I will connect the copper to the titanium with compression fittings and a pump inline, fill the loop with water, and plug the pump into my temp controller. I'm also considering backfilling the hole with aluminum shavings like someone in the DIY forum suggested before backfilling with sand, to help dissepate heat.

So i'm obviously not going to rush this because it's only february. I plan on buying the titanium from a guy on ebay, but if someone has another source for cheap that would be great.
 
That is a good question Vinny. I have no idea. I'm going to have to do some research on that and get back to you.
 
Two dissimilar metal mated together will cause corrosion, in this case, the copper will turn green and flake off right into your water stream. You should look into the new plastic waterlines used in newer homes instead of copper, Homedepot carries them with swage tools.

How are you going to coil the 10 feet of titanium? it will not bend like copper, or SS :lol:. You should consult a thermo engineer to see if 10 feet 3/8" tubing will give you enough surface area to get the BTU you need with your soil temp, I don't think so, unless your soil is below freezing all year around. 3/8" tubing is also a bit small for this application, it will be clogged with sponge and feather dusters in about a year, if you have good water quality.

Last thing, have you priced out titanium tubing? :eek2:
 
I had given thought to a geo also when building my tank. If I was keeping it, I was going to try wrapping tubing onto the cold water line in the house. That water is always around 50 or so.
 
Well it's going to be a closed loop. No tank water will be going in the pipes. plain tap water will circulate through the pipes, cooling the tank water, then being recooled underground. I'm going to look into how much corrosion using 2 different metals will cause, like i said i hadn't thought about it. But i can't imagine that water traveling through the 2 different metals will be a big deal. the 2 metals will not be touching each other, and a little corrosion on the copper isn't a big deal as long as it's not going to corrode through.

A few feet down the ground here is in the 50's year round. running 50 degree water through a 10 ft titanium coil should have a big effect on 85 degree tank water.

Using plastic tubing,( i assume your talking about pex)is very inefficient because it is too good of an insulator. I considered using radiant heat tubing, but copper will work much better.

I can get 3/8" titanium tubing on ebay for about 5 bucks a foot. even if i have to pay 10 a foot it will end up being less than buying a chiller. i also thought about bending it, but this guy said he bent it with a standard tubing bender, i'm sure i can find someone to do it for me if i can't. look at the pic at the bottom. http://www.guarriello.net/chiller.htm

Please don't take any of my comments as me not appreciating your advice. Keep it coming. I could certainly be wrong about the effectiveness. And i'm not totally sure about bending the titanium but it obviously can be done so it's worth a try.

And John cheapskate might be true. But mostly i dont have room for a chiller, and this room gets really hot as it is i dont need a chiller heating it up even more. Plus i'm already hiking up my parents elctric bill pretty well, i dont need any help with that.
 
After some quick research and thinking..... Titanium can cause galvanic corrosion to copper. however, they will not be touching each other anywhere, and if i use RO water it won't be very conductive. I'm sure it will leach things from the pipes and become conductive, but not enought for me to worry about it.

I'm thinking about connecting the copper to the titanium with vinyl tubing, so the copper wont even be in the same room as the tank, and it will insulate the water between the ground coil and the tank coil.
 
yeah, i want in on this too, so i can point out how ridiculous it is ever 5 mins....lol...j/k...i'll bring the beer
 
I was at a LIRA meeting where it was mentioned that a member built something under the ground. Not sure in his basement or not. However, the idea was by putting a storage container underground, there would be a natural cooling of the water.

The thing that may be relevant, was the speaker said that when he and the member discussed the effectiveness it was mentioned that this worked "too good", to the point where water coming up was very cold.

So I am not sure how you measure this, but maybe, and again, I have no first hand knowledge, you may not need a chiller, just a strong pump.

My thought on this, is maybe you have a shutoff valve that if it is too cold you don't use the deep in basement pit, and when it is hot you do.

Again, no first hand knowledge, expcept to say, that the member that did this said that it may not be practical because it worked too good (again, just relaying what I heard).

Hope this helps.

BTW, I would love to do this. So if you can, can you please keep us informed of the effectiveness.

Thank you,
 
That's basically the concept. water moving through the copper coil in the ground cools to under 60 degrees, then runs though the titanium coil and cools the fish tank water. After leaving the titanium coil the water will have warmed. It then cools again the copper coil. Keeps running in a loop. Hopefully it will have enough cooling power to not need a chiller.

The circulation pump will be plugged into a temperature controller. So once the water in the tank is down where it should be the pump will turn off and stop circulating water.

I chose this design over an "open loop" where fish tank water is pumped through the pipes for a few reasons.
1. I can make a much bigger loop underground in copper without having buy 50' of titanium. I am usign a 50' roll of copper because it's much cheaper and will never touch the tank water anyway.
2. I don't have to worry about tank water going stagnant in the pipes when it's not being used.
3. I don't have to worry about the pipes clogging up

Only problem is that it probably isn't as efficient as an open loop.
 
Im very interested.
Larry a controller will work fine for turning the loop on and off. Also it was Dave who gave the presentation of his.
Scott it sounds like you have everythingf worked out. Think my landlord will mind if i bust a hole in the side of the house? LOL Hes very cool with my fish tanks!
 
Chris, i'll bring over my hammer and chisel and we can bust a hole in your basement floor next. He'll never know.

Does anyone have any suggestions for a pump to use? I'm leaning toward an RO booster pump because i can get one with 3/8" fittings on it and i can hook it up easily. But i can't get gph ratings on them because they are not intended to be run alone, just to boost pressure. I also considered using a MJ but it would be pretty ghetto trying to hook it up inline.

I ordered a 50' roll of copper tubing from lowes, and i'm waiting on an estimate for the titanium.
 
Ive put enough holes in the wall already LOL I can pretty much do what i want as long as i repair it when i leave. Hes very cool that way :)
Im not sure on the RO booster pump. My guess is it wouldnt have the pressure needed to circulate the water thru the coil. I think youll have to get creative and who cares what it looks like its the functionality that counts!
 
ok so i'm still looking into pump choices. I'm considering a Taco circulator made for hot water loops in heating your house. I can gt 3/4" threaded flanges and bushing it down to 3/8". I'm afraid that going to be to much flow and isn't made to run with such small diameter pipe. I think it might be more flow than i need, but i'm sure i can get one used for like 25 bucks.

I am now considering an automotive 12v water cooler pump. It has 3/8" threaded inlet and outlet. moves between 1-2 gpm. any thoughts. I really dont want to par 200 bucks for it so i'm looking for cheaper options. but i'm liking it so far. suggestions please.
 
You must log in or register to reply here.

Similar threads

C
Hydros w/sump
Replies
3
Views
139
wvned
wvned
E
Which heater
Replies
13
Views
573
griss
griss
S
Help with Overflow Design Issue
Replies
0
Views
124
SFMAquariums
S
S
Re: bean animal help!
Replies
2
Views
153
wvned
wvned
S
Equipment mishap (Heater)
Replies
5
Views
215
wvned
wvned
Back
Top