LS7Corvette's passive peltier setup

[Long Haired Git]

In the end, the Peltier is an active-heatspreader.
In this case, its also being used to heat the water so that the radiator works more effectively as it will with a large difference between the coolant temperature and ambient air. Then, with the radiator reducing the temperature of the water, the passive-pump kicks in and we get flow.
BTW, you say above 150W for the heatsink, but in the OC article, you state 5v @ 10AMP = 50W for the TEC, which would mean the CPU is probably like 40W????

I'd really like to know, to a couple of decimal places, the inlet and outlet temps either side of the radiator. Yes, I know, not going to happen. From this and the watts going in, though, you can calculate the flow rate.

I love heatpipes - so very clever and powerful and maintenance free and quiet. The solution of using an array of heatpipes is clever. The issue of heatpipes on CPUs was always the size of the contact area for the evaporator, which the "active heat spreader" neatly solves.

What you ideally want is something the size and shape of a 120.2 heatercore, but instead of several parallel rectangular brass tubes carrying a liquid coolant, you want a series of heatpipes coming out of the copper block bolted to the hot side of the peltier.

Which then gets complicated due to the fixed nature of heatpipes (unless they make flexible ones now) and the sizes being discussed.

[JWFokker]

I don't know about using that Scythe with a peltier. It could barely cool a CPU running at stock speed in the reviews I read. Forget any overclocking. Adding a peltier would just make it worse. Why not try something like a Thermaltake Sonic Tower or Big Typhoon? They're both usable passively, with the option to use a 120mm fan, which can be very nearly silent. They're a bit more practical than the Scythe.

[Ls7corvete]

Max: WIth just one rad one block and little tubbing we dont need much coolant. So fluorinert can be done cheaply. Also can be done with alcohol as well.

LHG: I can pump up to 180w of heat with this TEC at 5v. That is the advantage of running a big TEC at low voltage. 150w was a bit high to be on the safe side. Coolant temps just isnt gonna happen, not with this setup, All I have is a coolermaster bay temp reader and I have taken enough critcism, hehe.

http://www.benchtest.com/heat_pipe1.html

[Ls7corvete]

Just thought you guys would be interested in a setop with a pump. My friend(RC64 on ocforums) was "inspired" by my setup and put this together.

DD maze4
320w @5v
csp mag
BIP w/M1A @7v shrouded

Prime temps:23c
Burnk7: 28-29

Venice core 3000+ running at 2700 1.55v

I will probably be going back to a pumped setup after I test the flourinert setup, something cheap maybe even a bilge pump as reliability is not a concern.

[jedi226]

So, has anyone tried this setup on the prescott yet? I would be willing to try but I don't really know much about these peltier systems so I'll need some help. But I really am interested in building a custom peltier and/or water cooling for my comp. I also won't be able to do anything until i buy a new hard drive or get a new one from seagate cuz it failed 2 days ago, still waiting for rma #.
Anyways I'm running a P4 3.0E S478. I've been doing a little research and from what I gather the TDP is ~90-100W. Am I right? So I need a TEC that will give me at least that at 75% capacity? I've been looking on e-bay for a TEC and i've found a 170W and the dimensions are 50mmX50mm which is bigger than my cpu chip so how does that affect this peltier design? that's all the questions i'll ask for now, i'll ask some more after these are answered. thanks

[Ls7corvete]

Originally Posted by jedi226

So, has anyone tried this setup on the prescott yet? I would be willing to try but I don't really know much about these peltier systems so I'll need some help. But I really am interested in building a custom peltier and/or water cooling for my comp. I also won't be able to do anything until i buy a new hard drive or get a new one from seagate cuz it failed 2 days ago, still waiting for rma #.
Anyways I'm running a P4 3.0E S478. I've been doing a little research and from what I gather the TDP is ~90-100W. Am I right? So I need a TEC that will give me at least that at 75% capacity? I've been looking on e-bay for a TEC and i've found a 170W and the dimensions are 50mmX50mm which is bigger than my cpu chip so how does that affect this peltier design? that's all the questions i'll ask for now, i'll ask some more after these are answered. thanks

Search around all these are simple TEC Qs that you can find, try different forums though there isnt anything along the lines of a tutorial sticky around these parts.

My design used an undervolted TEC so you will need one much bigger than a 170w, your system will also have to be adapted to the heat load you are planning as well(437w at 7-9v seems about right to me). Keep looking and LMK what you come up with, I am waiting for someone to get back to me on some P4 results with this setup.

[bobkoure]

If you're going to run without a pump (so using water heat differential to "drive" the water around the loop) IMHO you'd want the radiator "inlet" higher than the "outlet".
Try putting the rad on its side, so one pipe is higher than the other and see if there's any change. If there is, maybe think about something long-ish and single pass, so you can have the inlet 'way higher than the outlet. Like maybe the fedco 2-766 (14.188x3.25x1.625) single pass. Or if you don't want to figure out how to move air through something that odd a shape (I'd just cut a vertical slot in my case to fit and block all other inlets so whatever exhaust fannage you've got will pull air through the rad, the case, then out), then maybe a more square fedco 2-149 (7.75x6.125x2) - also single pass and lots easier to fit - although I'd guess you'd want the inlet higher than your heat source, so maybe the long, narrow one would actually be easier...
Oh - I have a little experience with using "no pump" cooling systems - tried cooling 2-stroke cylinder heads on a race bike long ago - worked fine so long as the "rad" (was a car heater core) inlet and outlet were at top and bottom - well enough that we could run leaner (2-strokes are also somewhat gas-evaporation-cooled) which meant fewer pit stops. Airflow through the rad was, as you might imagine, not an issue...

BTW, anyone who missed Cathar's Experiments in TEC based water chilling - go read that. Great stuff - got me interested in TECs again - thanks Cathar!

[Ls7corvete]

Just a lil FYI from messing around with the new PSU I got. The TEC @5v seems to be pulling about 7-8amps instead of the 10a that I predicted earlier.

more testing to follow...

[bobo5195]

for all those people who recommend gallium and liquid metals, it will never work.

Natural convection velocity is a function of 1/viscosity^2.

A big heatsink with the fins hanging vertically would work too but it is no where near as fun

[Ls7corvete]

Originally Posted by bobo5195

for all those people who recommend gallium and liquid metals, it will never work.

Natural convection velocity is a function of 1/viscosity^2.

Good advice, I saw this first hand messing with flourinert. I will have to try messing with fluids again after I get done testing the TECs.

Any ideas for a natural convection fluid?

[bobo5195]

water oddly enough is near as good as it gets.

I would suggest that for your loop the correlation with fluids goes something like

h is directly proportional to (beta/ viscosity^2)^n * k

maybe

h is directly proportional to (beta/ (viscosity*alpha))^n * k

where symbols are for fluids being their normal things
0.25<n<0.333

EDIT - had so many questions on natural convection of late that i may have to write an artical with a program for it. Had to do a beasty paper (Reached 8500, still could of added more) on it so i've read up.

So if you have a fluid plug the numbers and that is how it will perform relative to water. Should be easy to do for something like FC77 (flourinert). There are other realtions that i could post if your interested.

You could get hard number if you wish by pluging the numbers for your setup with a known liquid (near pure water) and then seeing what changing the numbers does.

[Ls7corvete]

Originally Posted by bobo5195

water oddly enough is near as good as it gets.

I would suggest that for your loop the correlation with fluids goes something like

h is directly proportional to (beta/ viscosity^2)^n * k

maybe

h is directly proportional to (beta/ (viscosity*alpha))^n * k

where symbols are for fluids being their normal things
0.25<n<0.333

EDIT - had so many questions on natural convection of late that i may have to write an artical with a program for it. Had to do a beasty paper (Reached 8500, still could of added more) on it so i've read up.

So if you have a fluid plug the numbers and that is how it will perform relative to water. Should be easy to do for something like FC77 (flourinert). There are other realtions that i could post if your interested.

You could get hard number if you wish by pluging the numbers for your setup with a known liquid (near pure water) and then seeing what changing the numbers does.

Would be interesting to see what comes out of the equations, I have wondered if other fluids might work better in this setup.

[bobo5195]

doubt there is anything. something lower viscosity maybe an it s abit hit or miss that this is how your system is working.

I'm fairly sure water (maye with some special additives is your best bet unless there is some superuper fluid on the web.