Pro/Forums - View Single Post - Building a 12 tec chiller to decrease power usage. Yep, decrease.

gruntledweasel · 04-13-2004, 09:57 PM

I picked up one of those thermotek chillers off ebay for cheap a while back. I'm still modding it to suit my needs (flow restrictions galore in that thing!), but one thing bugs me a bit. The darn thing's rated to draw more current than my full size fridge, and I'm going to be cooling a loop dumping 170-190 watts or so into it. I think that might put it fairly close to its peak power draw. I don't pay for electricity, but that kind of inefficiency seems a bit silly if I can do something about it, you know?

I had an idea when I saw an auction like this on ebay for a bunch of 72 watt pelts. (Don't be fooled by his numbers, qmax != max watts drawn). I got 15 for about three dollars each. I'm building a "prechiller" into the unit using some parts I've just got sitting around. I've got a few of those koolance hard drive cooling blocks sitting around, and it turns out six 40mm TECs will fit quite nicely on each side of one. Playing around with kryotherm, I can see that twelve TECs of roughly similar specs (HAIL module) running at 2-3 volts can cool a pretty hefty heatload down to below ambient without drawing much current at all (~20W at 2V, ~50W at 3V, entire pelt array), even with a crappy C/W for the coolant system and TIM joint.

So I'm going to build a prechiller out of three of those hard drive coolers and a small radiator and pump I've got sitting around (previous crappy WC setup, I've long since upgraded). The two "hotside" blocks are in their own loop, cooling one chiller block sandwiched between them. The assembly ought to fit in the thermotek box where the dehumidifier assembly used to sit. Dumping 50-100 W of heat out via this second loop should let the actual chiller unit run its pelts at a lower voltage and let me push the water temp farther below ambient.

I've done some preliminary testing to see exactly what voltage I want to run the peltiers at (the thermotek unit's still in pieces pending the purchase of some stuff, so I can't do a test with the final setup). It's looking like 3V might be the way to go. I did a quick test with two pelts stacked, but that didn't yield much of a deltaT improvement.

Just as an aside...I'm well aware of the problems involved with inline chillers. Bear in mind that I'm only augmenting a setup that's already "chiller-only" (no radiator inline). The only way this'll hurt me is if the coldside temp of the peltier is actually greater than what the equilibrium temperature of the water would be without the additional chiller inline. This would only happen if the thermotek unit were running all-out on a heatload significantly smaller (80W less or so) than what I will be putting into the loop.

I know much better could be done (koolance equipment =

), but this is a "I had it sitting around anyway" kind of mod. Thoughts? I promise I won't make scatological remarks about others' neural equipment if my idea needs improvement.

04-13-2004, 09:57 PM	#1
gruntledweasel Cooling Neophyte Join Date: Dec 2002 Location: Irvine Posts: 63	Building a 12 tec chiller to decrease power usage. Yep, decrease. I picked up one of those thermotek chillers off ebay for cheap a while back. I'm still modding it to suit my needs (flow restrictions galore in that thing!), but one thing bugs me a bit. The darn thing's rated to draw more current than my full size fridge, and I'm going to be cooling a loop dumping 170-190 watts or so into it. I think that might put it fairly close to its peak power draw. I don't pay for electricity, but that kind of inefficiency seems a bit silly if I can do something about it, you know? I had an idea when I saw an auction like this on ebay for a bunch of 72 watt pelts. (Don't be fooled by his numbers, qmax != max watts drawn). I got 15 for about three dollars each. I'm building a "prechiller" into the unit using some parts I've just got sitting around. I've got a few of those koolance hard drive cooling blocks sitting around, and it turns out six 40mm TECs will fit quite nicely on each side of one. Playing around with kryotherm, I can see that twelve TECs of roughly similar specs (HAIL module) running at 2-3 volts can cool a pretty hefty heatload down to below ambient without drawing much current at all (~20W at 2V, ~50W at 3V, entire pelt array), even with a crappy C/W for the coolant system and TIM joint. So I'm going to build a prechiller out of three of those hard drive coolers and a small radiator and pump I've got sitting around (previous crappy WC setup, I've long since upgraded). The two "hotside" blocks are in their own loop, cooling one chiller block sandwiched between them. The assembly ought to fit in the thermotek box where the dehumidifier assembly used to sit. Dumping 50-100 W of heat out via this second loop should let the actual chiller unit run its pelts at a lower voltage and let me push the water temp farther below ambient. I've done some preliminary testing to see exactly what voltage I want to run the peltiers at (the thermotek unit's still in pieces pending the purchase of some stuff, so I can't do a test with the final setup). It's looking like 3V might be the way to go. I did a quick test with two pelts stacked, but that didn't yield much of a deltaT improvement. Just as an aside...I'm well aware of the problems involved with inline chillers. Bear in mind that I'm only augmenting a setup that's already "chiller-only" (no radiator inline). The only way this'll hurt me is if the coldside temp of the peltier is actually greater than what the equilibrium temperature of the water would be without the additional chiller inline. This would only happen if the thermotek unit were running all-out on a heatload significantly smaller (80W less or so) than what I will be putting into the loop. I know much better could be done (koolance equipment = ), but this is a "I had it sitting around anyway" kind of mod. Thoughts? I promise I won't make scatological remarks about others' neural equipment if my idea needs improvement.