# DIY chiller from dorm fridge.



## Chappy (Aug 1, 2011)

I have seen one of these being built, and then someone comes out and says it cant work. Does anyone know for sure if you can make a chiller from a dorm fridge. The idea is to drill 2 holes (inlet and outlet). Coil as much hose as you can in the fridge, and then pump water from your tank through the coil and back to the tank. I know you need a fridge with a freezer, remove the frame work from the freezer so that the thermocouple for the ice maker will hang down into the fridge.
I have a fridge and before I destroy it I would like to know if this can work. The No's say the water in the hose coil, will not cool enough to work, 

has anyone actually seen one that works, I am also hoping to leave enough room in the box to fit a 6pk


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## blindkiller85 (Jan 8, 2011)

Google is your friend beyond my opinion.

Instead of playing with the internals of the fridge and possible making it not work for your benefit of a chiller and a fridge is your call. 

What I would do is make the fridge a radiator more or less. Calls for a lot of experimentation. 2 lines in and out, a coil of a PC radiator. The experimentation with it and getting it to where you want it to is the issue with still making the fridge work. 

Too much chilling power for the tank, means your fridge is always running and not staying cold. Too little and then you just wasted your time anyways, and might freeze components in the fridge/freezer and have a fish tank in there too! None the less without a refugium, you're going to have 2 zones if they are both competing for equality in the tank. 

It all comes into play with 3 things. The coil you're using, water flow, and temperature of the fridge/freezer. Thinking more in-depth about this I would get a PC radiator, get 2 lines in and out and run them into the freezer where I would put the PC radiator and run it back out into a refugium. 

My refugium setup would be easy. On the left (or right) you have the heater, and the other side is the lines coming from your "chiller". Have the sump pump in the middle on the bottom. Try to make some circulating current to even them out where you want using the "chiller".

So this calls for - 12 ft of hose to use, a PC radiator, a pump through the "chiller", a sump pump for a refugium, and a bigger heater to make sure your water doesn't get too cold as well. But you still have to play with flow and temperature in the fridge/freezer to get the temperatures where you want them. As well as the coil which you might end up needing 2 for the absorption of the colder air making it a chiller, instead of a fancy waste of money.

Personally, I'd just save my pennies and get a real chiller.


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## TheOldSalt (Jan 28, 2005)

I have read about a lot of failures with this, but no successes.


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## Chappy (Aug 1, 2011)

thanks for the replies. like the old saying goes, if it sounds to good to be true it usualy is. I may play with it just for grins, but I am not expecting much.. Like Thomas Edison said " I did not fail, I found 60,000 things that don't work" ( OR SOMETHING SIMILAR TO THAT) don't get on me for an incorrect quote it was to get the idea across.


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## blindkiller85 (Jan 8, 2011)

Chappy said:


> thanks for the replies. like the old saying goes, if it sounds to good to be true it usualy is. I may play with it just for grins, but I am not expecting much.. Like Thomas Edison said " I did not fail, I found 60,000 things that don't work" ( OR SOMETHING SIMILAR TO THAT) don't get on me for an incorrect quote it was to get the idea across.


It's "I haven't failed, I've found 10,000 ways not to make a light bulb."

I would honestly say to take my advice. Drop the freezer to it's lowest settings and use 1-2 PC radiators with line through it. Worst case scenario and it doesn't work anyways, then plug the holes instead of messing with anything mechanical within the fridge/freezer.


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## lohachata (Jan 27, 2006)

i don't know much about actual chillers ; but i have thought of doing this before...to me ; the biggest problem would be temperature control...in an aquarium you need a stable temp..that would be pretty tricky to accomplish with the small fridge...not sure that controlling the flow rate would affect the temp control....


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## buzz1167 (Sep 23, 2011)

I have a 2 x 120mm PC radiator you can have if you want to do it... Its pretty decent sized...

But I still haven't gotten why you aren't just stuffing the internals of the fridge in the sump? That will work for sure, just as long as you don't break everything when you do it. You might could even use the fridge thermocouple if it goes high enough.

Anyway, I would also go with the common recommendation of running the hose to a radiator in the freezer and dropping a fan on that thing.

What I haven't figured out yet is the control system... Might you just take a second pump and use a thermocouple system to turn it on when the water gets above a certain temp and off when its below a certain temp? 
Where do you get something like that? Maybe its not that expensive? Might could build it, but you'd need lots of crap laying around...

Regards,


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## Mikaila31 (Nov 29, 2009)

yeah the issue isn't really if it works, its if it can hold a stable temp. Just a hose run through a fidge won't be able to hold a sable temp in a tank. The more hose you run through the fridge the more you will cool the tank, but it will be in relation to the room temperature. If your room temp goes up your tank temp will because the amount of energy your removing from the tank is now less then the energy going into it. 

I've run an airline through a 55watt power compact fixture. Then pumped water from the tank below through it and back into the tank. It worked and the tank temp did rise a reasonable rate. Under most conditions it would work fine since it only kicked the tank about 3-4 degrees higher then the room. The tank heater picked up any slack. Issue would be if the room temp got within 3 degrees of optimal tank temp. I could of gotten the tank a lot hotter if I ran more tubing.


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## emc7 (Jul 23, 2005)

Temperature probes aren't expensive, but controls are. Using a temp. probe to "unplug" a heater plugged into a controlled power source is one way to avoid cooking fish, but its too expensive.


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## Mikaila31 (Nov 29, 2009)

I think it would be possible to use a termostat from an aquarium heater. If you wired it so that it instead completed a circuit to turn a pump on and off. Issue here is you would still need a heater like object in the tank to monitor temp.


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## bmlbytes (Aug 1, 2009)

emc7 said:


> Temperature probes aren't expensive, but controls are. Using a temp. probe to "unplug" a heater plugged into a controlled power source is one way to avoid cooking fish, but its too expensive.


That is such a shame. I hate when I see things like this and realize, "I could build something that does exactly that for $5". Seriously, the microcontroller used as the controls would cost less than $5. Its a matter of designing a circuit, which I could probably do in about 20 min or less. I am seriously thinking of starting open source aquarium electronics to allow people to build their own homemade aquarium equipment. 

All this would need is a thermo-coupler/thermistor, a 120v relay and a simple microcontroller circuit and you have a cheap, fully functional, copy of the much more expensive controls.


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## webma (Nov 10, 2011)

That is interesting. I never thought about building a chiller on my own. Unfortunately I do not think that I can do it anyways because I am not that technically talented. I will need a chiller soon because my old one broke and in order to bypass the time until I have a new one I am currently using a chiller rental which is perfect but in the long run I will definitely need a new one.


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## Mikaila31 (Nov 29, 2009)

bmlbytes said:


> That is such a shame. I hate when I see things like this and realize, "I could build something that does exactly that for $5". Seriously, the microcontroller used as the controls would cost less than $5. Its a matter of designing a circuit, which I could probably do in about 20 min or less. I am seriously thinking of starting open source aquarium electronics to allow people to build their own homemade aquarium equipment.
> 
> All this would need is a thermo-coupler/thermistor, a 120v relay and a simple microcontroller circuit and you have a cheap, fully functional, copy of the much more expensive controls.


Couldn't you take a cheap heater thermosat and modify it? It would still be difficult though. If you control a pump on/off you need to make sure the tubing in the fridge is positioned so it doesn't potentially freeze when the pump is off.


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## redpaulhus (Jan 18, 2005)

This is a thermodynamics question.
Its physics 101 (or maybe 301) - delta tee
or to put it another way - how much BTU (heat) can a dorm fridge remove from a large mass of water (keep in mind that even a 10 or 20g tank way outmasses the amount of beer in a dorm fridge).
Most dorm fridges might - might - handle 100 - 200 BTU per hour.

With evaporative cooling ( a fan on the tank etc) you can pull out about 8000 btu/hr. 
For way less money and effort.
Heck even a window AC unit will work better than a dorm fridge.

I played with this years ago and never saw any appreciable results.

Here's a good article if you want to look at the physics and engineering:

http://www.beananimal.com/articles/dorm-fridge-aquarium-chiller.aspx


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