# Geothermal cooling- anyone have any experience?



## CodyS (May 7, 2013)

Hi all,

The stranger is back!

I am wanting to do a geothermal cooling system... for my fish tank. Was just wondering if anyone has any experience with this type of thing?

I am wanting to do it under a concrete slab to be laid in my new room.

Might as well chuck in a few pics while I am at it!

http://i1263.Rule #2/albums/ii632/codysheridan1/null_zps741f4bf5.jpg

http://i1263.Rule #2/albums/ii632/codysheridan1/null_zps168ddc24.jpg

http://i1263.Rule #2/albums/ii632/codysheridan1/null_zpse3e53348.jpg


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## Kevin (May 7, 2013)

Awesome pics Cody. Is that a clownfish? 

Hope to see you posting again even if your woodworking is on hold for a while.


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## Outdoormarsh (May 7, 2013)

Hmmm.. I've heard of geothermal heating, which is deeper drilling I'm guessing. So are you just wanting to drill a shallow hole and cool the water underground?


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## Mike1950 (May 7, 2013)

What is the ground temp? Running pipes under the slab would work to cool here -water temp out of ground here is a constant 55 degrees +-. I passively cool my shop........


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## CodyS (May 9, 2013)

Mike1950 said:


> What is the ground temp? Running pipes under the slab would work to cool here -water temp out of ground here is a constant 55 degrees +-. I passively cool my shop........



Ground temp is cold, not sure exactly. I think I remember reading 16 (60f) degrees somewhere. This sounds about right to me.

What system did you use?


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## CodyS (May 9, 2013)

Outdoormarsh said:


> Hmmm.. I've heard of geothermal heating, which is deeper drilling I'm guessing. So are you just wanting to drill a shallow hole and cool the water underground?



The aim is to have it under/just at the bottom of a concrete slab.


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## jimmyjames (May 9, 2013)

Back when I lived on a farm with a pond I had a 750 foot geothermal pond loop hooked to me 1400 gallon reef tank, I used it strictly for cooling, didn't need any heating, the lights and equipment kept it plenty warm even in the winter months, saved me a ton of money from having to purchase a gigantic chiller. I researched in ground geothermal stuff but the cost of having a ground loop put in is astronomical.....


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## brown down (May 9, 2013)

As long as you keep in where the temp won't rise for instance they trench about 4-5 ft by me to get it below the frost line. It will maintain a constant temp. How many gallons are you planning on circulating? If you are going under a slab where no sun will make the ground heat up you should be ok. How deep we're you planning on going under the slab?


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## woodtickgreg (May 9, 2013)

back cody! Good to see you here again. Did you ever get that sawmill finished? Would love to see some pics of that.


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## CodyS (May 9, 2013)

brown down said:


> As long as you keep in where the temp won't rise for instance they trench about 4-5 ft by me to get it below the frost line. It will maintain a constant temp. How many gallons are you planning on circulating? If you are going under a slab where no sun will make the ground heat up you should be ok. How deep we're you planning on going under the slab?



The slab will be in a room, like a basement, It has been excavated out of rock, I was hoping to not have to dig down anymore to incorporate this, as it all has to be done by hand (concrete saw, mash hammer, rock chisel   ).

I was hoping to do it at the bottom of the slab if possible.

Here are some pics of the room in question:

http://i1263.Rule #2/albums/ii632/codysheridan1/null_zps8e87904c.jpg

http://i1263.Rule #2/albums/ii632/codysheridan1/null_zps24ebd677.jpg

http://i1263.Rule #2/albums/ii632/codysheridan1/null_zps491afef6.jpg

The tank is planned to be about 2500-3000L (660-790g). Part of this will be placed in the sun outside to take advantage of sunlight for coral propagation so I would imagine that will be a significant load to cool in summer.

I was thinking a heat exchanger might be a possibility too for winter don't know if they are worthwhile though.

Also we are pretty much at sea level so I don't think frost will be an issue...



woodtickgreg said:


> back cody! Good to see you here again. Did you ever get that sawmill finished? Would love to see some pics of that.



Thanks Greg :)

 not yet, the parts are sitting around, just need to spend a couple more grand getting the rest, and that isn't going to happen if I keep spending all of my money on fish lol. I will get back round to it at some stage and will be sure to continue documenting it when I do.


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## Mike1950 (May 9, 2013)

cody.sheridan-2008 said:


> Mike1950 said:
> 
> 
> > What is the ground temp? Running pipes under the slab would work to cool here -water temp out of ground here is a constant 55 degrees +-. I passively cool my shop........
> ...



Easiest way to find ground temp in your local is get the temp of someones well water- usually close.
I built shop new and as I said Passive- slap is insulated on perimeter with 3" extruded polystyrene foam 2'deep. Thus the center of slab wants to stay cool. Shop yesterday with low 80's outside was a very comfy 68. From your pictures you have been working hard!!! You have to put piping below concrete otherwise expansion and contraction is hard on pipe. You need quite an area to be effective otherwise it will not work. My GUESS is you are not showing a large enough space to make it effective. Also an active system gets very spendy. Passive solar/geo-thermal heating/cooling is the only way to go. Maybe an air to water heat exchanger.......... Good luck -Beautiful fish.


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## brown down (May 9, 2013)

Mike1950 said:


> cody.sheridan-2008 said:
> 
> 
> > Mike1950 said:
> ...



Mike is right as far as price goes. a solar unit pays for itself well geothermal does as well but isn't as costly for the initial install. in the states average solar panel will run you about $1000 but that was a few years ago when i did a solar panel job, 1800 panels to be exact... they prob went down like everything else does over time!! solar panels actually store energy in them like a battery for a short time after the sun goes down and run at about 70% on a cloudy day!!

for the size tank you are trying to regulate, mike is also right on the amount of piping you are going to have to do and thats where it gets real costly real fast. once installed they are great, only energy used is the pump to circulate the water in the pipes, but IMO your better off going with solar. 
I don't know about your country but here in the states, you can back feed it onto the grid and watch your meter spin backwards! the power companies hate it but oh well! someone down the line will use it


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## jimmyjames (May 9, 2013)

For geothermal to work the ground loop has to be spread out in a wide area, with a coil of like thrown into a 5' deep by 5'x5' square its not going to do much, the amount of btu's that your going to introduce into that small area is astronomical, especially with 800 gallons, all its going to do is slowly heat that small chunk of earth, geothermal ground loops normally go very deep into the ground in several locations spread out over a wide area , and that just enough btu's too cool air, cooling water is much more difficult. If I were you I wouldn't bother with it and just use led lighting, some fans for evaporative cooling and a good dehumidifier in the room, choose pumps that are more efficient with lower wattage draws, the less watts a pump takes the less watts of heat it introduces into the water, also reducing your daylight hours in the tank helps as well, I know many people with 6 hours or less of daylight on they're tank and they're corals grow like weeds.......


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## CodyS (May 18, 2013)

thank's for the input guys :) Have decided against using this.


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