Post Rad Chiller Concept

[zipdogso]

If you read the first few pages of the thread, this model here is EXACTLY what this thread was originally about.

Ohhh....so I did comprehend you correctly originally then......when I said any theory placing a rad in the same loop as a TEC is flawed....it is, really.

Right, I am planning to have a fan on it. The heatsink is actually fairly large... It's a Swiftech MCX462... Over 450g of copper/aluminum pins. Their site rates it at .29c/W with a 20dBA fan. I had originally thought that I would take a 80W 16v Peltier and just plug it directly into my PSU's 12v rail, to get some better efficiency... But you guys seem to indicate I would be better off taking like a 226W 16v and running it at 7v(12v/5v rail molex thing)?

As it happens your plan of an 80w at 12v would get you a highish Dt for 60w cooling .... A voltage drop from 16v (actually 15.6v) to 12v is standard fare because that gets you the best cooling/high input voltage ratio but don't confuse this with efficiency even at this point TEC's are damned inefficient. Efficiency comes at the other end of the voltage scale but it's not a given right and can be difficult to achieve.

If you only want cooling by a few degrees it is not easy (with a high Dt.) but it is more achievable if you use a large TEC undervolted quite a lot - this will give you a low Dt and hence your low temp reduction requirement it will also give you better efficiency (so long as your under 50% - but the actual Dt is critical for efficiency.). BUT to get it all to work you must have very good cooling on the hotside.

What I don't understand, is that people used this particular heatsink with 226W 16v pelts undervolted to 12v right on top of CPU's at sub zero temps... This is the EXACT heatsink I have, just it doesn't have the pelt or coldplate.
http://www.swiftnets.com/products/mcx462plusT.asp
Which they rate at:
# Heat dissipation capacity: 70 Watts continuous thermal load to ambient temperature with 80CFM fan.
# Maximum continuous thermal load: 100 Watts

Hmm yeah well I think most decent heatsinks with a big fan on will go 100-150w. Probably they count on people not realizing what you have.....they want people to buy the whole unit not just the heatsink...go figure...
Actually in reality undervolting to 12v knocks a chunk off the 226w cooling then there are the inevitable thermal transfer inefficiencies You might be surprised at the amount of cooling some people are getting from 226's....certainly nothing like 226w. I will hanker that those 226w units are not exactly that in the first place, anyway.

Anyway, I wasn't looking for a huge amount of cooling. Just a little more at high loads.

The whole point of using a TEC is to get things COLD not just knock off a few degrees - TEC's arent really designed to run like that - If your ambients not too high you could find it easier/cheaper to use a dedicated CPU only water loop.