DIY Mini-fridge chiller

[jamiehill]

I picked up a mini-fridge on Craigslist a while back for cheap with the thought of trying to make a chiller out of it. I finally got it done and it has been running for about a week now. Between the hot weather a few weeks back and my lights, I was having trouble keeping my temp down below 82.

With the new chiller, the tank has been staying pretty steady between 78.5 and 80 degrees.

Here are some pictures of my DIY chiller. I try to keep the fridge running at around 40 degrees. Of course, when the pump has water going through it the fridge warms up a bit. It usually stays below 60 though.

Inside the fridge with the hose coiled up.

Inside the fridge where the water comes in and goes out.

Hoses giong into the back.

Full tank shot with the fridge next to it.

 

[theJ]

I think thats an awesome idea, sounds like its working out pretty well! Are you using a controller? I think I read you mention that in a different thread. I see you can keep drinks in there too

 

[jamiehill]

Yeah, the drinks are nice. Especially with the computer right next to it. Reach over and grab a can . I am using a Reefkeeper to control the pump that pushes the water through the fridge.

 

[Damsel13]

hi theJ

Gaby is going to get after me about hijacking.......

 

[Scooterman]

You know I have this setup in my full size fridge but it is used for cooling water for the filtered water on the door, to me so little water is cooled it is almost useless, I'd bet it has at least 50ft of hose also but 1/4". So maybe you can break down the materials used & exactly what you got going in & out & how much does it chill your tank? I like the idea you can also use it to chill your beer or whatever also LOL!

 

[Krish]

Looks like a cool idea! Hope it continues to work for you

 

[DonW]

If you dont run the pump 24/7 its going to turn into a nitrate factory. A few times a day allows the the bacteria plenty of time to start breaking down nutrients the older it get the worse it will be.

Don

 

[jamiehill]

If you dont run the pump 24/7 its going to turn into a nitrate factory. A few times a day allows the the bacteria plenty of time to start breaking down nutrients the older it get the worse it will be.

Don

That is a good point. I didn't think of that. I will have to keep an eye on how often it is running. Lately it has been running about 12 hours a day.

Edit - Isn't that how chillers normally run though? Don't they only pump water when they are on? Or do they always pump water and the chilling portion of it turns on when the tank temp gets high enough?

 

[jamiehill]

You know I have this setup in my full size fridge but it is used for cooling water for the filtered water on the door, to me so little water is cooled it is almost useless, I'd bet it has at least 50ft of hose also but 1/4". So maybe you can break down the materials used & exactly what you got going in & out & how much does it chill your tank? I like the idea you can also use it to chill your beer or whatever also LOL!

1 mini-fridge
about 75 feet of 1/2" flexible PVC
2 90 degree elbows - 1 side JG fitting for the flexible PVC, the other 1/2" MPT
2 1/2" threaded nipple fittings
1 Rio 2100

I used a 1/2" drill bit to drill 2 holes in the back of the fridge to run the 90 degree elbows & threaded nipples through.

Coiling the PVC was the hardest part. It would have been much easier with an extra set of hands, but the wife was out for the day . I wound the PVC around an upside down instant ocean bucket to get the coils tight enough. I used some duct tape every couple coils so that it didn't lose the tightness. After coiling up the hose and getting it into the fridge, I removed the tape and allowed the PVC to expand to fill the area.

I have my reefkeeper set to kick the pump on whenever the temp gets above 79. I have a ball valve on the output of the chiller hose to control how fast the water comes through.

 

[cwby416]

I had a similar DIY chiller. I found that I got much better results with about 200' of tubing, and had the tubing in the fridge submerged in water. The new one I'm working on is going to have around 500' of tubing I also ran my 24/7 to avoid any nitrate problems.....I believe what DonW is talking about is that by having the 75' of tubing, you have a much greater surface area for the bacteria to grow on...Chillers only have a short distance and usually use some sort of metal (may be titanium? i'm not sure) that is probably not as easy for the bacteria to grow on during the down time...

 

[burning2nd]

howa about a freezer......
with the tubeing coiled in a frozen block of water

 

[DonW]

I had a similar DIY chiller. I found that I got much better results with about 200' of tubing, and had the tubing in the fridge submerged in water. The new one I'm working on is going to have around 500' of tubing I also ran my 24/7 to avoid any nitrate problems.....I believe what DonW is talking about is that by having the 75' of tubing, you have a much greater surface area for the bacteria to grow on...Chillers only have a short distance and usually use some sort of metal (may be titanium? i'm not sure) that is probably not as easy for the bacteria to grow on during the down time...

Chillers have NO down time the pump runs 24/7 thus no issues.

Don

 

[Scooterman]

I don't think this would work well on my tank, I have a 1/4hp chiller & it has to work hard to keep the temp down. So to cool constantly I don't think a 1000 foot of coil would get cold enough quick enough. This may be good for a tank that doesn't get hot or not much heat is added to the tank, can't think it would work on a reef tank, to me the money on a chiller would be worth the extra cost initially, well unless your keeping some beers in there, then yea I should get one

 

[kriswaters]

I looked into chillers, and even thought of the DIY one as above...I have two mini fridges. But, I also have AC....thank goodness, and so far so good.

I like the idea though...it was exactly what I was thinking.

Kris

 

[star rider]

what if it were closed system (semi closed) tubing from fridge is submerged in the tank to cool surrounding water.like a drop in chiller..
(I'm just thinking out loud)

 

[DonW]

what if it were closed system (semi closed) tubing from fridge is submerged in the tank to cool surrounding water.like a drop in chiller..
(I'm just thinking out loud)

Sounds like a novel idea but the plastic tube is a insulator and you would have to keep it very close to freezing which would make it hard to control. You could also use antifreeze but I wouldnt want a plastic tube with antifreeze in my sump. The best choice would be Ti, but its so expensive you might as well buy a chiller.

Don

 

[star rider]

Sounds like a novel idea but the plastic tube is a insulator and you would have to keep it very close to freezing which would make it hard to control. You could also use antifreeze but I wouldnt want a plastic tube with antifreeze in my sump. The best choice would be Ti, but its so expensive you might as well buy a chiller.

Don

interesting..I was just thinking if it assists at dropping the temp a degree or two the cold water would circulate continuously in the tubing..chilling the tubing
but it might be more a pia than it's worth.