What happens to Tec 172W 24V if 12V?

[Since87]

Originally posted by bigben2k
Les' graphs seriously contradict your statement, where you say that 2 * 176 might be 2 deg cooler than a single 220, where Les' graphs show a difference of 0 to 20 deg C, depending on who's rig is observed. (voltages being different though).

It's not clear to me that Les's data contradicts my guess at all. The pelt operating voltages used in the systems compared are not listed. I was specifically talking about running two 172 Watt pelts at 12V (49% of Vmax) as compared to one 226 Watt pelt at 12V (79% of Vmax). I don't see any indication that the dual pelt systems shown on Les's graph were running at 12V.

If you want to understand the basis for my guesstimate, study this document. (Be warned, it is a long download at 56kb.)

[Les]

Originally posted by Since87
Les,

1) Thanks for the data. Can you point me to the thread where this is discussed. I looked around the site. A lot of interesting stuff being discussed there.

2) I'm not following everything you wrote. I haven't been able to find a reference to "Waterloo calculations". Is the graphed data arrived at by running the processors at different frequencies to get different "radiate" Watts?

Having seen you mention it somewhere, I have been using 0.1C/W as a single pelt/die Rc. I had written a crude pelt calculator spreadsheet before I learned of the Kryotherm calculator. With it, I was able to match JoeC's test results for the Swifttech air cooled pelt fairly accurately using 0.1C/W for Rc, and 0.22C/W for Rh. (Compare to 0.26C/W for JoeC's die simulator measurement of the MCX462+ alone.)

Apologise for tardy response but................ and Xmas.
1)Perhaps the most pertinent threads are shown below.In the "bigforum" threads the links do not work directly - due to forum name/coding/"something else" change but links to my jpgs are still live.
http://www.bigforums.co.uk:81/viewto...ghlight=#66733
http://www.bigforums.co.uk:81/viewto...ghlight=#76620
http://forums.overclockers.com.au/sh...5&pagenumber=2.
2) No link to any "Waterloo calculations" was given - the 0.09-0.16c/w are the "isothermal Waterloo calculations" for a 40x40x6mm cold plate.Processors were run at different frequencies and v-cores to get the different wattages .

[Since87]

Les,

Thanks for the info. The stuff about localized coolant boiling was interesting.

I'm curious. Whether instead of "boiling" it might be localized cavitation. Cavitation should be easier to achieve at higher temperatures. Did you see erosion of the copper in the water channels?

I'm far from an expert on this stuff, but I would expect such cavitation to occur particularly at sharp bends in the channel. With the newer Maze2 channel design, locations near the "center of the TEC's" would seem to be prime candidates.

[Les]

Originally posted by Since87
Les,

Thanks for the info. The stuff about localized coolant boiling was interesting.

I'm curious. Whether instead of "boiling" it might be localized cavitation. Cavitation should be easier to achieve at higher temperatures. Did you see erosion of the copper in the water channels?

I'm far from an expert on this stuff, but I would expect such cavitation to occur particularly at sharp bends in the channel. With the newer Maze2 channel design, locations near the "center of the TEC's" would seem to be prime candidates.

It was possibly a bit of a flight of fancy to envoke "flow boiling" or "cavitation" (possibly only a terminology difference). It was early days in my on-going Krytherm education and was envisaging much higher hot-side temps than now would .
Maybe conditions are optimised in one of Volenti's many creation :-
http://forums.procooling.com/vbb/sho...k&pagenumber=1