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Peltier - DIY chiller

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Folks, I have a problem with my 12G nano tank: it's in my office and they don't have AC running over the weekends...
My temp logger shows the tank shot to 85 both days. :-(

I've been having a wild idea: stick a peltier chiller to the glass of the tank. That way, no complicated plumbing or water contamination concerns... but I am concerned the temp differential on the glass may shatter it...

Anybody wants to jump in with an opinion?

Thanks

-Fred
 
Warning! This is just a guess!!!!

Since water is such a good conductor (it's possible to boil water in a paper cup!), as long as there is always water in the tank covering the area of the cold spot, you should have no problems. As long as there is good flow over the area, I wouldn't think the glass would ever get that cold.

Have you tried using a fan to cool it? Much lower 'geek factor' but they work. :)
 
The cold temp is unlikely to be an issue. Glass/water will conduct heat in so fast, it will be fine,
and probably never even be noticeably cold.

The only real concern is the thermal expansion of the peltier itself.
Don't glue it to the glass. Suggest lots of thermal grease, and some sort of weak-pressure mount.
As it expands and contracts, you want it to be able to move.

You might want to insulate that tank as much as possible also.
Especially on the side with the peltier chiller. It will generate a fair amount of heat
that you need to keep away from the tank.
 
Most likely a fan that blows air across the surface of the water in your tank will do all you need. You'll evaporate water faster, but it's much cheaper/simpler than a peltier setup.
 
Excellent!
Regarding cost, I'm not paying for the electricity going to that tank :)
For the mount, I'm thinking about epoxying a bracket to hold the fan, peltier and radiator, so I should be able to mount it loose accounting for expansion.
Good idea to insulate the back glass from the heat generated by the hot side of the plate.
Another idea I was toying with was to use a laptop CPU heat sink to move the heat away from the surface.

-fred
 
Even if you aren't paying for the electricity, I would still go the fan route. It's a much better utilization of all the energy we share. :)
 
IMO, simply cooling one part of the glass is not going to be sufficient to bring down the thermal mass of 12g of water. Glass is a fairly good insulator, and probably won't pull heat as well as you think, plus any air gaps between the TEC and the glass is going to further compound on your cooling woes.

You really want some thermally conductive material that's in direct contact with the TEC to get it to work, unfortunately most thermally conductive material isn't exactly something you want to submerge in the tank (aluminum, copper), some stainless steel could work, or titanium, but those are expensive options.

Now if you already have the TEC and just want to play around with it, by all means go for it. But I wouldn't rush out to buy parts getting it to work just yet.
 
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