Small Chiller Recommendations

So the system that I'm setting up has roughly a 7 gal insulated rez that will need to be cooled. It's in a garage in Southern California that gets over 100*F in the mid of summer. I'll be installing an AC to cool the grow tents, and the rest of the garage will be cooled passively.

I foresee root rot with this scenario and want to cool the water but do not know what to go with for such a small rez.

Ideas I've come up with:
* Ice probe
* http://www.ebay.com/itm/Aquarium-Thermostat-Chiller-Heater-Adjustable-72W-Fish-Tank-Salt-Fresh-Water-/282033379947?hash=item41aa7fda6b:g:FDEAAOSwa~BYQkCJ
* A DIY "chiller" with a 60W Peltier (similar to the link above, but way cheaper)

What do you guys suggest?

Oh, I normally would just get like a 1/13HP chiller for this and not worry about the extra power. Unfortunately a fridge was just put into the garage and I don't want the excess amperage draw as this is on 1x 20A breaker.

Update: I'm going the DIY route. I'll be using a 60W 40mm x 40mm Peltier cooler, a 41mm x 41mm water cooling block, a high end CPU fan, a small water pump, a 12v adapter, some tubing and thermal paste/glue. Temperature (on/off) will be controlled with my Arduino hydroponics controller. I had everything except the Peltier and the cooling block already, so this only cost me about $17. Once I get it all rigged up I'll post details.

How about something different. Dig a hole 4' down and 4' wide in the ground. Lay a coil of 50' of 3/4" black plastic pipe. Seperate teh coils with soil as you fill it up. Leave enough pipe on both ends. They need to go to a bucket with a pump. Fill it with water it should stay ground temp at 50-55 degrees.

friedguy said:

Update: I'm going the DIY route. I'll be using a 60W 40mm x 40mm Peltier cooler, a 41mm x 41mm water cooling block, a high end CPU fan, a small water pump, a 12v adapter, some tubing and thermal paste/glue. Temperature (on/off) will be controlled with my Arduino hydroponics controller. I had everything except the Peltier and the cooling block already, so this only cost me about $17. Once I get it all rigged up I'll post details.

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So youve chosen to waste $17 lol. Sorry man, a peltier will almost certainly not work.

Jaybodankly said:

How about something different. Dig a hole 4' down and 4' wide in the ground. Lay a coil of 50' of 3/4" black plastic pipe. Seperate teh coils with soil as you fill it up. Leave enough pipe on both ends. They need to go to a bucket with a pump. Fill it with water it should stay ground temp at 50-55 degrees.

Click to expand...

Something along this route is probably your best option for least power usage.

So I've done some research on geothermal cooling and it seems like it could work. Here's a good read on the subject.
http://www.homeintheearth.com/tech_notes/basics-of-earthsheltering/earth/soil-properties/soil-temperature-experiment/

I already have about 80 feet of 5/8 tube, the pump and adapters, and I just purchased an aluminum heat exchanger (for $20) to keep the rez and cooling systems separated.

I'll first setup the peltier cooler and test it and post the results. Then I'll be digging a 4'x4'x4' hole (well, my son will, lol) and running and burying the tubing. Then I'll setup the geothermal cooling system and post the results.

I hope this can help someone else in a similar situation.

So for both of these possible solutions I've spent under $40 so far.

If both don't work good enough then I'll be replacing the 20A circuit to the garage with a multi-wire branch circuit (either 30 or 40 amps) to the garage. Then I'll have enough juice to run a proper chiller.

Shugglet said:

So youve chosen to waste $17 lol. Sorry man, a peltier will almost certainly not work.

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They work GREAT!!!! I can chill a 5 gallon cooler to 66F with no fluctuations in the middle of summer in the garage. They are not hard to make or you can buy an ice probe on ebay but they are expensive, i have both pics listed below. It uses 55 watts and runs for about 5 to 7 hours a day in the middle of summer which cost $1.17 to run per month.







Here is my homemade peltier cooler, works the same as the ice probe. Water temps stay perfect all your round no matter how hot it is. The only part that goes into the cooler/reservoir is the small immersible pump.

Peltier modules will work for very small amounts of water but they do add the heat removed to the grow space. As for the ground loop, they work great, I have 200' of copper tube buried under ground and circulate glycol though it, it stops working when ground temp gets to around 65. I just built a chiller for about $200 all in Its a tad over powered for 5 gallons though and a water cooler mod would be a better choice