Redneck DIY Chiller?

[HawkeyeDJ]

Redneck DIY Chiller

Problem: My QT tank is located in the garage. An uninsulated garage can reach 95 F+ in my area.

Got me thinking about how to keep a tank cool (frag tank, QT, etc) in the garage during the hot summer months in the U.S. Southwest without breaking the bank.

Hypothesis: I can keep a tank cool using an ice chest, some tubing, a return pump, and a thermostatic controller.

I could put a large quantity of ice (10 lbs+) in an insulated ice chest, run a length of water tubing through the ice with one end as an overflow and the other hooked up to a return pump. Control the return pump with an Inkbird type thermostatic controller, thereby maintaining a sufficiently cool tank.

I could put water in ziplock bags, freeze them, put them in the ice chest in the morning, refreeze them at night.

What's wrong with this plan?

 

[glb]

After Hurricane Irma it got up to 92 in my house. We put frozen water bottles in the tank twice a day and saved everything. But I will say that the ice melts very quickly, so I don’t know if it would be a practical long term fix.

 

[KStatefan]

It has been a few years since thermo so check my data

10 lbs of ice will absorb 1439 btu during the phase transition. It takes 8.3 btu removed to lower the temp of 1 gallon of pure water 1 degree F. so you ten lbs of ice would lower the temp of 173 gallons 1 degree.

 

[MnFish1]

If I were you - I would buy a chiller. Depending on how many days you're thinking you'll need it. You will be buying/needing a lot of ice - which over time will also 'break the bank'. Additionally, at least a chiller will in theory turn off if its cool at night - whereas ice is going to continue to melt. JMHO. Interesting idea

 

[HawkeyeDJ]

After Hurricane Irma it got up to 92 in my house. We put frozen water bottles in the tank twice a day and saved everything. But I will say that the ice melts very quickly, so I don’t know if it would be a practical long term fix.

Here's the difference between your crisis and my challenge: You put the frozen water bottles directly in your tank, exposing the ice to warm temperatures with no insulation for the entire day.

I would have my ice bags in an insulated box, which would only be exposed to the heat of the water circulating through the tubing.

Temperatures being equal, I think my ice bags would last longer than your ice bottles in the tank.

And BTW, sounds like you were quick thinking during Irma. Well done!

 

[HawkeyeDJ]

It has been a few years since thermo so check my data

10 lbs of ice will absorb 1439 btu during the phase transition. It takes 8.3 btu removed to lower the temp of 1 gallon of pure water 1 degree F. so you ten lbs of ice would lower the temp of 173 gallons 1 degree.

Fortunately, my QT tank is only 10 gallons.

 

[glb]

Here's the difference between your crisis and my challenge: You put the frozen water bottles directly in your tank, exposing the ice to warm temperatures with no insulation for the entire day.

I would have my ice bags in an insulated box, which would only be exposed to the heat of the water circulating through the tubing.

Temperatures being equal, I think my ice bags would last longer than your ice bottles in the tank.

And BTW, sounds like you were quick thinking during Irma. Well done!

You’re right, that is a completely different situation! It’ll be easier with a smaller tank.

 

[MnFish1]

Fortunately, my QT tank is only 10 gallons.

For 10 gallons - I think your method will be fine - I was picturing a major system with frags/etc. In any case - it would probably be cheap to 'try'

 

[HawkeyeDJ]

If I were you - I would buy a chiller. Depending on how many days you're thinking you'll need it. You will be buying/needing a lot of ice - which over time will also 'break the bank'. Additionally, at least a chiller will in theory turn off if its cool at night - whereas ice is going to continue to melt. JMHO. Interesting idea

Chillers start at over $500 and go way up from there. I'm thinking my freezer in the kitchen can freeze a lot of water bags for $500.

Remember, the ice is not in the tank. It is in a separate insulated cooler. The only time the cooler would be active is if the controller says the tank temperature is too high. As soon as the temperature returns to normal the controller shuts off the circulating pump.

 

[MnFish1]

Chillers start at over $500 and go way up from there. I'm thinking my freezer in the kitchen can freeze a lot of water bags for $500.

Remember, the ice is not in the tank. It is in a separate insulated cooler. The only time the cooler would be active is if the controller says the tank temperature is too high. As soon as the temperature returns to normal the controller shuts off the circulating pump.

Yeah - I thought you were trying to do like a 100 gallon frag system. IMHO you're all good

 

[MnFish1]

Chillers start at over $500 and go way up from there. I'm thinking my freezer in the kitchen can freeze a lot of water bags for $500.

Remember, the ice is not in the tank. It is in a separate insulated cooler. The only time the cooler would be active is if the controller says the tank temperature is too high. As soon as the temperature returns to normal the controller shuts off the circulating pump.

Yeah - I read it - for a 10 gallon tank - I would personally not do what you're doing - but - its all good - put it in your house - and forget about it. But - just to play devils advocate - what happens when the ice is melted - on a hot night - at 1AM

 

[davidcalgary29]

Wouldn't evaporative cooling be more effective in such a dry climate? The use of a sump could double available surface area, and an ATO system filled with a (thawing) frozen water source could provide additional cooling.

 

[HawkeyeDJ]

Yeah - I read it - for a 10 gallon tank - I would personally not do what you're doing - but - its all good - put it in your house - and forget about it. But - just to play devils advocate - what happens when the ice is melted - on a hot night - at 1AM

Well, that's part of the challenge. Could I keep the ice in a insulated cooler through the night? Would it be possible to keep it cold for 12 hours, then add more ice bags at the end of the day? The second part of the challenge is would the water returning to the tank be too cold, creating a brief shock to the system? Won't know unless I try it.

Right now I have nothing in my QT, but I have it set up and cycled in the event I need it on a moment's notice. I have no room for it in the house and the coming summer heat is a concern. I'm just spitballing here to see if I'm overlooking anything.

 

[EeyoreIsMySpiritAnimal]

Wouldn't evaporative cooling be more effective in such a dry climate? The use of a sump could double available surface area, and an ATO system filled with a (thawing) frozen water source could provide additional cooling.

The southeast us is hardly a dry climate...

 

[HawkeyeDJ]

The southeast us is hardly a dry climate...

Southwest. Mostly dry in the summer.

 

[EeyoreIsMySpiritAnimal]

Southwest. Mostly dry in the summer.

Sorry, I mis-read your post.

 

[HawkeyeDJ]

Wouldn't evaporative cooling be more effective in such a dry climate? The use of a sump could double available surface area, and an ATO system filled with a (thawing) frozen water source could provide additional cooling.

The problem there is the ATO activates based on water level, not water temperature. Second, putting the ice bags in a sump would expose the ice to high temperatures all day long, melting it very quickly. I need the ice to last all day while I'm at work.

I do think a fan blowing across the surface would be helpful in addition to my proposed cheapy chiller.

 

[MnFish1]

Well, that's part of the challenge. Could I keep the ice in a insulated cooler through the night? Would it be possible to keep it cold for 12 hours, then add more ice bags at the end of the day? The second part of the challenge is would the water returning to the tank be too cold, creating a brief shock to the system? Won't know unless I try it.

Right now I have nothing in my QT, but I have it set up and cycled in the event I need it on a moment's notice. I have no room for it in the house and the coming summer heat is a concern. I'm just spitballing here to see if I'm overlooking anything.

Right - I mean - I suppose you could just set up a routine - whereby you fill the ice every night. But I guess I would think about this. a 20 lb bag of ice is about 4$. A cooler will (depending on the size) keep it frozen for about a day (thats assuming its totally closed) - you're going to be running water constantly through it - but lets assume its $4/day for the ice. Then there is the price of the cooler, the pump, the controller, etc. - then the work. So - if you look at it that way (again assuming the ice cost is correct) - thats $25 a week, $100/month and in 5 months you've paid for your chiller.

 

[davidcalgary29]

The problem there is the ATO activates based on water level, not water temperature. Second, putting the ice bags in a sump would expose the ice to high temperatures all day long, melting it very quickly. I need the ice to last all day while I'm at work.

I do think a fan blowing across the surface would be helpful in addition to my proposed cheapy chiller.

I was thinking more along the lines that a fan-based cooling system would evaporate large amounts of water, and that an ATO system with frozen/cold water in a type of large styrofoarm cooler drilled with an outlet line might be used as the replacement water. Wouldn't that keep the water source cool for longer periods of time with minimal heat gain through the small drilled hole?

 

[EeyoreIsMySpiritAnimal]

It sounds like a good experiment! Please let us know how it works out!