DIY chiller help

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Look into cold plates used by bars for their tap setups. They usually contain 20+" of tubing coiled inside a metal plate. This is placed inside a freezer or on ice and when the beer runs through it the temp can drop by over 10* in just a few seconds. You could use a pump or powerhead to push the water through something like this to cool it down.
 
Oughtsix said:
In all practicality a keg/tank cooler would only work if you like drinking your beer at the same temperature you want to keep the tank?

My suggestion for a long tube is based on surface area and heat exchange. The Rena filter has a small surface area with relatively non heat conductive plastic. I question how much heat the Rena casing will give up. A copper tube would be great for heat exchange but I have read that copper is not good in tanks???? Plastic tubing is a pretty decent heat insulator so you will have to make up for this with a longer run.

You will want to set the refrigerator at the temperature you want the tank water to be at. If you set it considerably lower than your desired tank water temperature you will have troubles keeping your tank at a constant temperature. With a long tube the exit temperature should be very close to the refrigerator temperature.

While the tank is initially cooling you will need to remove heat from the water plus any heat the tank collects from the atmosphere. Once the tank reaches the set temperature you will only need to remove at much heat as the tank collects from the atmosphere to maintain the tank temperature once the system reaches an equilibrium.

A large diameter smooth wall tube, say 1" or so, should provide minimal back pressure.

Having to pull the filter out from the refrigerator every time you need to maintain the filter sounds like a pain.

Hunting down a leak inside the confines of a compact refrigerator doesn't sound like it would be easy. A continuous run of tubing inside the refrigerator would have practically no potential for leaking.

I have a XP3 but I forget if it is a totally submersed pump? If it is air cooled then you are disipating the pump heat as well as the water heat inside of the refrigerator. If it is a submersed pump then it doesn't make a difference since all the pump heat is going into the water.

These were my reasons for suggesting a plastic tube... feel free to evaluating their validity for your project.
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i have also heard that copper is not good for a fish tank, this thought had crossed my mind as well, and as for the tubing i was going to stick with the plastic tubing that comes with the rena, you should know what that tubing looks like since you have a xp3. it seems pretty thick i think it will help keep the water cool as it runs through the lines thats if i can get the canister to cool down. the only issue i have with making a longer run with my hoses inside the fridge is that i think the rena would lose its flow rate giveing the tank less overturn per hour. thats just my thought

the mini fridge i picked up isnt so mini lol, i could fit the rena XP4 inside, this is why i dont see it being a hassle to have to open the door and flip the quick release on the lid and remove the filter. with my xp2 inside there will be lots of room, hopefully for adding some more insulation.

and i think the rena pump is air cooled, i dont believe its submersed
 
Inglorious said:
Look into cold plates used by bars for their tap setups. They usually contain 20+" of tubing coiled inside a metal plate. This is placed inside a freezer or on ice and when the beer runs through it the temp can drop by over 10* in just a few seconds. You could use a pump or powerhead to push the water through something like this to cool it down.
Click to expand...

thats a cool idea thanks, i will look into it

and it sounds like expanding foam is the way to go, thanks guys for all the info
 
Inglorious said:
Look into cold plates used by bars for their tap setups. They usually contain 20+" of tubing coiled inside a metal plate. This is placed inside a freezer or on ice and when the beer runs through it the temp can drop by over 10* in just a few seconds. You could use a pump or powerhead to push the water through something like this to cool it down.
Click to expand...

I think the problem you are going to run into is thermal transfer. I think a cold plate is a perfect fish safe heat exchange solution as I believe most of them use stainless steel tubing. I see several on ebay in the $100 range. It looks like most have pretty small diameter tubing. I have a feeling that you are going to need a different pump than your XP4 filter.

Give the filter in the fridge a try and let us know if it works?
 
will do, im just finishing up a pipeline project in the next day or two and then i will be home to set this project in motion. ill try to get pics on here by the weekend. thanks for all the advise guys
 
The main issue I see is that you won't have any way to control the temperature. Many chillers come with a built-in temperature controller, others use an external controller. Without that the temperature of the water will fluctuate with the air temperature, not good for cold water fish. If you hook the fridge up to a temperature controller it could work, but by that point you might as well just buy a chiller. A temperature controller will cost over $100, plus the cost of the fridge.

In the end I think that a chiller would be more reliable, easier, more efficient, and not a whole lot more money.
 
Dan F said:
The main issue I see is that you won't have any way to control the temperature. Many chillers come with a built-in temperature controller, others use an external controller. Without that the temperature of the water will fluctuate with the air temperature, not good for cold water fish. If you hook the fridge up to a temperature controller it could work, but by that point you might as well just buy a chiller. A temperature controller will cost over $100, plus the cost of the fridge.

In the end I think that a chiller would be more reliable, easier, more efficient, and not a whole lot more money.
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ive found my house doesnt flucuate to much. i do have a 90 gallon tank right now that is running with no heater at night wen the lights go out the tank gets down to 75f and during the day it stays at 76.5f i am hoping that if i can start the entire volume of water at like 60-65f that the fridge will maintain the water temp. this is really just a learning experiance i havent been able to find a proper chiller for my tank for less then $400 and so far i have only spend $80 on a used bar fridge, i do understand what youre saying about how the fridge wont beable to kick in if the tank temp starts to climb but i guess we will see what happends. this is the hole point of DIY right, try and be creative to save money. im just hoping for the best
 
What is the temperature range of the thermostat in a mini fridge? What is the temperature you should keep a cold water fish tank at?

With a big enough heat exchanger I figured you would use the thermostat in the fridge to set the temperature of the tank. If you don't have a a big heat exchanger then I think you will have temperature fluctuation problems.

I wasn't thinking of an external tank referenced thermo-controller... but $70 isn't too bad if it will handle the wattage of the fridge. This might be a good idea.
 
well i have had the mini fridge pluged in for about an hour and a half now and it is at 53F wich is about 12 degrees colder then my desired temp, and the fridge is set on its warmest setting, in an hour or so i will check if the temp has changed and then i will crank it up and see just how low i can drop the temprature. this will be a rainbow trout tank and for the winter months i want to get the water 65F and in the summer months i want 76F at the hottest. right now with no heater my tank is sitting at 74F so i need to drop it 9 degrees, im feeling pretty good about the fridge doing this considering i dont even have it turned up yet.
 
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