just curious... why would the AC unit be a bad idea? you can make a thermostat that can connect directly to the radiator to detect rad temps and chill to a certain temp. i just don't understand why this is a bad idea. excuse my ignorance... but whats wrong with it?

Couldn't a TEC controller just be made with a t-balancer driving a relay or a power resistor?

Or just a simple curcuit with a thermistor and a variable resistor switching the TEC on above a certain temp.

Ofcourse precision might be a bit off, a digital thermometer and a PIC controller could make it much more accurate (as accurate as the digital thermometer) and easier to vary between different temperatures. No complex circuit would be needed for that, just a bit of knowledge with programming PICs. Add a 16x1 lcd display and there might just be a small market.

@Nugit and moonlightcheese
yes, but you'd get something like these:
http://www.omega.com/ppt/pptsc.asp?ref=CN132
http://www.ttiglobal.com/Product.aspx?ProductID=3411
examples.
which there is a vast product range, and prices.
but, again, expensive for the private buyer.

Aqua Medic Titan 150 model use tecs to cool the water and have controllers on them. It seems these saves on time and hassle of build your own setup or repairing one. I can't comment on quality since i never used it. CoolWorks IceProbe uses the same idea but it seems more of a hassle than aqua medic. Most of the chillers use condensor type/phase change smiliar setups.



http://cgi.ebay.com/Aqua-Medic-Titan...QQcmdZViewItem
2nd one has two chillers for one auction.
http://cgi.ebay.com/Aqua-Medic-Titan...QQcmdZViewItem

INFO
http://www.marinedepot.com/aquarium_...an.asp?CartId=
http://www.aqua-medic.de/cgi-bin/php...lang=en&pos=35

That only cools 150w though, a dual 320 watt setup would have considerably better performance (if constructed correctly).

Agreed on 320 watt setup being more powerful and cheaper, but is 150 Watts not enough to keep water temps stable for testing purposes?

If you put the max watts through the TEC then you will get 0c temp drop.

I don't like standing next to a AC all day long. Way to much noise.

I will need at least 300watts to keep things were I want them. Thats why I figured 2 tecs over 300watts and then half the power to each of them. Should work out. I plan on making my heat die variable from 50watts to 150watts. And then the pump it self is like 55watts. I figure 300watts should be enough to drop the temps below room temp if room temp goes above 25C.

I think that will work.

I assume you are going to insulate the system, this should improove efficency by allot if you do a good job :)

Edit - there is a thread on the PSU / controll system here - http://forums.procooling.com/vbb/showthread.php?t=12147

I was able to start moving into my new place and I think I might not have to worry about chilling the water. THe new place not only has an A/C already in the room but the whole place is cool all day long as it is shaded. :) I was in there at prime heat time today and it was about 70F. As were my old place is about 85F this time of day and thats with A/C. I will get the test bench setup and do my first round of testing without the chiller and see what happens.

I am still going to build this chiller though. Just might not do it as soon as I was planning.