Colin (Jul 14, 2001 02:25 a.m.):
BTW, the dual 120s were installed today. I picked up another 109 MHz to en up at 1704 MHz with 2.04 volts. Temps running Prime are 19C with at 27.4 C ambient. I have not let it idle long enough to establish an idle temp. The cold plate is at - 4.5 C.
Colin
Most interested to see that you have resumed your dual peltier experiments and thank you for reporting your initial results.
A couple of questions and muses/ramblings:-
Have you measured the peltier thickness yet?(Please)
Am I right in assuming the 120s are 24v Drift types and the -4.5C corresponds to an idling state;additionally that these preliminary results are slightly better than those for the dual 172watt set-up(ambient 26.3C, water load 36.2C, CPU load 19C, water idle 35.5C, CPU idle -3C[ I think])?
I don't know whether you have fed the data into the "Kryotherm predictor" but it give a temp of 18.5C for a 120watt load(Thunderbird@1700and 2.04v) cooled by 2x120watt (20v),ambient 27.4C,a good waterblock(Rh=0.15) ,rubber insulation(Rins=0.84),and near perfect cold junction(Rc=0.001).For a load of 25watt(Idle??) a temp of -4.4C is predicted. I chose rubber as the insulator because(1) it gives the best around fit with the results and (2) although above 0c a more realistic choice maybe polyurethane foam, below 0c the formation of ice(70X the thermal conductivity of polyurethane) may change the Rins parameter to be more akin to rubber.
Interestingly(to me) is that although using polyurethane should drop the idle(25watt??) temp by 12c there is only a predicted drop of 2c in loaded (120watt) temps.I feel this could be of particular signifance,in addition to the major role of a good waterblock, in the "large temp differential between idle and loaded temps" problem in peltier cooled systems.
Think I have rambled enough so am off to the pub where it is the norm.Hoping you continue to report your findings.
Les
