fridge chiller????

tgp4274 · Aug 1, 2017

ok so I'm thinking it's about time for a chiller...
I've built almost everything from the tank to the scrubber. ;)
been thinking about building one of those chillers using a mini fridge...
I have a controller to run it when needed
my question is do I run the fridge all the time and hook the pump to the controller
or do I run the pump all the time and have the controller turn the fridge on and off..

I know that afew guys n gals have done them in here so am hopeing for input
thanks peeps :D

Caseyoidae · Aug 1, 2017

That's a great idea, I just plugged my window ac into apex. Is that a kitty pool reef in your avatar?? Need pictures of that!

Hazmat312 · Aug 1, 2017

I don't have one, But i think it would be better to leave the fridge on and have the pump run on the controller. That way the pump is not adding to your heat problem by constantly running in your sump, and when you do need to use the chiller the fridge is already cold and ready to rock so your not waiting for the fridge to reach temp.

tgp4274 · Aug 2, 2017

Caseyoidae said:
That's a great idea, I just plugged my window ac into apex. Is that a kitty pool reef in your avatar?? Need pictures of that!

Yes it is :-)
Tank had a seam let go n I had that as a holding for everything till I built the new tank....:-D

AlexG · Aug 2, 2017

I agree with leaving the fridge running all the time and having the pump on the controller. Plus you could leave a few cold ones in the fridge or some phytoplankton.

Tuffyyyyy · Aug 2, 2017

People have been trying to figure this out in the water-cooled computer community for a while. The issue they have found is that the computers need to be cooled constantly, which burns out the fridge's compressor in a short amount of time. If your water is being heated all day by something (T5s?) then the fridge needs to run all day to get to your desired temperature, and they're just not built for that.

tgp4274 · Aug 2, 2017

Tuffyyyyy said:
People have been trying to figure this out in the water-cooled computer community for a while. The issue they have found is that the computers need to be cooled constantly, which burns out the fridge's compressor in a short amount of time. If your water is being heated all day by something (T5s?) then the fridge needs to run all day to get to your desired temperature, and they're just not built for that.

true..... but for the price of the chiller I can buy like 5 mini fridge's.......

lion king · Aug 3, 2017

I never built it because I'm able to keep my temp in check with a fan and a controller. But this is how I figured it out. The pump runs continually with the tubing coiled inside the fridge. Then you use one of these to control the temperature of the fridge. https://www.amazon.com/dp/B0002EAL58/_encoding=UTF8?coliid=I38PS1SWW08LS3&colid=30LWZU9C856GV Whether it will work or not, I don't know; just throwing it out there.

tgp4274 · Aug 4, 2017

ah cool thanks
not worried how to control temp as I have a reefkeeper controller so am going to use that to turn on and off to control temp
am wondering tho...... about the water sitting in the hose and becoming stagnet when the pump isn't running because of the tank not needing to run the chiller

KStatefan · Aug 4, 2017

How much capacity does a mini fridge have?

lion king · Aug 4, 2017

tgp4274 said:
ah cool thanks
not worried how to control temp as I have a reefkeeper controller so am going to use that to turn on and off to control temp
am wondering tho...... about the water sitting in the hose and becoming stagnet when the pump isn't running because of the tank not needing to run the chiller

That's the point, the water runs continually. Managing the temperature of the fridge is how you control the temp of the tank. You set the fridge temp just as you would set the temp of a chiller, using a controller like the one I listed or connecting the fridge to your apex. The water will flow through the fridge and maintain the temp you set the fridge at, the fridge will turn on and off to maintain. You coil the hose inside the fridge to give more surface area of water to be cooled.

Ocelaris · Aug 5, 2017

Mini fridges have really weak compressors, so regardless of methods, do the math with the btu you need to bring down the tank temperature against the btu of the mini fridge. Jbj has a good calculator. For my 110 to bring it down 3 degrees with my lights and pumps, I would need a 1/5 hp chiller. I'll second the above posters comments about computer modders trying for years to use them without avail. I've used it for full sized fridge before to cool a computer, ad it was a pain. Keep an eye out on your local forums for good deals, a used chiller can be had for a few hundred dollars.

I looked at what it would cost to get just a titanium heat exchanger for air cooling, but they seem to be the bulk of the cost of the chiller in the first place. If you have a heat exchanger, running two separate loops might be easier.

Rays2k · Aug 5, 2017

Interesting idea, but doesn't seem worth it in the end.

Rufus’ goofs · Aug 5, 2017

How fine of on/off timing does your intended controller have?

I'm wondering if you could have your large coiled hose on a delay, like on 15 seconds, off 45 seconds and when your temperature rises on full. Wouldn't have as large a cooling effect, but help preserve the compressor, as well as alleviate the stagnant water issue.

Wait... I'm not sure that it would preserve the compressor. o_O

Might not be worth trying at all. Just got me thinking.

Sleepydoc · Aug 6, 2017

Beananimal has a nice write up explaining why this isn't a good idea...
http://www.beananimal.com/articles/dorm-fridge-aquarium-chiller.aspx

Shon · Aug 8, 2017

I see.. pushing tank water into a fridge and then back again?

If I was a gambling man, I'd think a second closed system in a Chest Freezer could do it.

A reservior in the freezer, filled with mineral oil (freezes at -30c), external inline pump, pumping into a stainless wort chiller located in sump, back to the fridge/res; running the pump off a thermostat set at a 5° temp swing. Fill every void of the freezer with ice blocks to keep system more efficient.

But.. once you add up the $150 freezer(Walmart ArticKing 5cf), $60 wort chiller (25ft), $? ?gph pump, $20 a gallon of mineral oil @ ?gallons... etc. wouldn't a normal chiller be a better choice?

Also, I have drilled fridges before, not fun. Best kegerator ever though.

Sleepydoc · Aug 8, 2017

Even still, most chest freezers still probably couldn't handle the load, either. Freezers are better insulated and have a lower thermostat than refrigerators, but in terms of the compressor BTU capacity they probably don't differ significantly from refrigerators. (I did a quick web search and couldn't actually find any BTU ratings or even Watt ratings for small chest freezers.) Filling with metal oil would increase the thermal mass and likely aid in the conduction of heat, but ultimately wouldn't change the amount of heat the system had to remove.

I think this is another case of 'the cheap man pays the most!'

ndrwater · Aug 8, 2017

Interesting idea, but as mentioned above, a used chiller can be had for less than the price of a mini fridge. Couple that with all the what-if's, time and materials to make the mod only to find out it just might not work.
Just for gitts and shiggles, I looked up chillers on my local Craigslist, and a 1/5hp chiller can be had for under $150.
Fwiw, I have 2 chillers. One bought new, and a 1/5 HP I bought for $125. Both been running strong for 4 years....

Donovan Joannes · Aug 8, 2017

Chest freezer will be my choice. Drop in SS or aluminium box (at least 1 feet deep), run your silicone coil in it and fill with RODI. Let it freeze, turn on your pump and your have ice cold water running. Drop some ice cubes from the store to cover the box, a few dozen of beer won't hurt either. The pump should continue running so that the water won't freeze. I am afraid you won't be able to keep corals, king crab should be fine thou :D.