DIY Mini-fridge Chiller?

[electricbluelizzy]

Has anyone ever made a DIY Chiller from a Mini-fridge? I've seen a lot of DIY Kegerators in college made from refrigerators. A mini-fridge can be had for practically nothing if you catch the graduating college kids. I have three..

Couldn't you just spiral some tubing in the refrigerator and back out, running on a powerhead? And have the heater further on in the sump for fine tuning the temperature?

Anyone know any reason why this wouldn't work. Seems like all you would need would be the fridge, a drill and some of that insulating foam spray folks use to winterize their house windows...

Whaddya think??

EBL

[rockster2599]

I think people try stuff like this but dont think its ever really successful due to a couple of things. In order to get adequate cooling of the water as it passes through the fridge you need the tubing to be made of a good heat exchange material or to be very long. Good heat exchange materials tend to be metals which corrode or leach when exposed to sea water (commercial chiller use titanium $$$$$). Long pipe= bigger pump=addition of the heat you are tring to remove. Also I dont think most minifridges would have the power to chill the water at the rate you would want to pass the water through the system (i.e. for it to be effective on a large tank).
Just theories, never tried it myself.
Rockster

[Eric P]

This would probably work if there was enough tubing coiled in the fridge. The way I would regulate it would be to put the powerhead on a temp controller. You could probably get a used controller cheap. The tubing is the tricky part. Plastic or rubber tubing does not transfer heat well. The only metalic tubing you could use would be titanium, or possibly 316 series stainless. The titanium is the best but most expensive way to go. It might be worth a try with lots of plastic tube (I would say a couple hundred feet).

Good luck, Eric....

[Doug1]

Also the more successful ones seem to immerse the tubing in a water bath inside the mini fridge to maximize heat transfer. If you use plastic tubing find the stuff with the thinnest wall and no bigger inside that 1/2" ID, 3/8 might be even better, FWIW

[Geoff]

i have made 2 DIY chillers. i have the write-up for one here. this does work, but thee are a lot of considerations that need to be addressed. most have been mentioned. the biggest being plastic is a great insulator. not what you want when building a chiller. for each of my chillers i used at least 75' of tubing. i think i still needed more. you have to submerge the tubing in water to even have a decent chance of cooling the aquarium water. a dorm fridge with its normal 1/10 hp compressor is way underpowered for anything but a small nano.

the two i have made use a 1/5 hp compressor. the one listed above uses a water fountain cooler to cool the water bath. the one i am using now uses a room A/C unit. the cooling coils were removed an placed in a 10g igloo cooler. this is not a small chiller. it is capable of cooling my 125g but just barely. i have the water bath set to 40 degrees. i have 100' of tubing in the water bath. i have a thermometer in the water bath to monitor it. when the tank needs cooling, i can see the temp in the water bath rise to nearly 50 degrees.

is it worth it, up to you. my new one cost me about $150 to make. i am sure i am running it a lot more than if it was a commercial unit. so i am loosing money every day using it due to the increase in power consumption. so long term, DIY chillers not a good idea. short term, they will work, but near as good as you think it will.

G~

[Steve-O]

I guess the hardest thing is not to build it, but how to control it.

Great write up on yours Geoff.

[Geoff]

Originally Posted by Steve-O

I guess the hardest thing is not to build it, but how to control it.

Great write up on yours Geoff.

Thanks!!!

yea, i cheated. i have an Aquacontroller II to do this for me. i think Jimbo did a wite up on temp controllers in this forum somewhere. you might want to do a search for temp controllers and see if it pops up.

G~

[VWD]

People have try it for years , Don't think it works very well ,You will have to really slow down the water flow , to get the transfer rate , I think the price of chillers have really gone down over the past few years ,So if Temp is a concern I think it would be worth checking in to getting one that You can control . Vince

[VWD]

I did Read the DYI from Geoff, looks good and But that is alot better then the small compact frig. But also looks to be alot of work , But I'm sure You can get a used water fountain at a good price and that would save money , Vince

[Geoff]

Originally Posted by VWD

I did Read the DYI from Geoff, looks good and But that is alot better then the small compact frig. But also looks to be alot of work , But I'm sure You can get a used water fountain at a good price and that would save money , Vince

that one was free.

being at a University they had to replace all of the in wall fountains with handicap fountains so these were being tossed. the only way i could justify the experiment to see if it would really work. the water fountain cooler was good because the cooling vessel was a solid chuck of copper. wrapping the tubing around that gave it good contact so the insulating properties of the tubing was somewhat negated by being in direct contact with the cold metal.

G~

[concept3]

You mean like this? LOL

I keep the house around 68-70 degrees year round anyway, and I figured since I have an old college fridge sitting next to the 55 to give it a shot. It only brings my temperature down a MAXIMUM of 5 degrees, which is all I need since I have multiple fans on my setup, one over sump and two blowing out of my DIY hood housing 2 X 250 watt Halides and 2 X 110 watt VHO's.

Pump is an old school fluval 202 with very slow water flow........verrrryyyy sllloooooowwww......

Yep, it's only a 55 with 720 watts of light.

Did I mention that it's only a 55 gallon?

[jagt48]

What about a mini freezer running not as much piping through it? I've seen them at Wal-Mart for like $130.

[Geoff]

Originally Posted by jagt48

What about a mini freezer running not as much piping through it? I've seen them at Wal-Mart for like $130.

you need to run as much tubing as possible through it. the readily available tubing that is used is a good insulator and not a good conductor. what that means is that the tube needs to be very long so that the warm tank water will not heat up the entire tube and make the chiller for the most part useless. being a good insulator means that the inside of the tube can warm up quickly and not really affect the outside of the tube. the longer the tube the less this effect occurs. by the time the tank water gets to end of the tubing it has hopefully cooled down enough from heating the beginning part of the tube that it is actually starting to really trop in temp.

if the water leaving the tube is not as cold as the water bath inside the DIY chiller than it is not working real well. if the circulation pump for the tank water were to stay on extensively then eventually all you will be doing is heating your water bath and not really cooling the tank.

G~

[Whale4]

Having a good understanding of refrigeration I would say yes techniclly it would work but.......As someone else said you need to coil it up in a standing bath of H20. Another idea for ideal heat transfer would to have whats called a Tube in Tube Chiller where you have lets say a peice of 1/2" INSIDE a peice of 7/8" tube with the cool water on the inside of the 1/2" and the water TO be cooled in the 7/8" but these are tricky, due to the pumps and supply water ect. One place you can check for a premade tube in tube is any beer making supply store they use them to cool 5 gallons of wort from 212 degrees to 45 degrees within minutes and they are fairly cheep 50$ or so for a cheap one.






Going Where The Water Tastes Like Wine- Jerry