Post Rad Chiller Concept

[NaeKuh]

so u guys are telling me to water the hotside with half the TECs?

Or do i paralell and aircool the hotside?

That is the question im asking.

And lets assume i end up getting 5 x 226W tecs. i know im never going to run them at full blast, so what PSU should i be looking at?

The meanwell S600-12?

[Uncle Jimbo]

so u guys are telling me to water the hotside with half the TECs?

Or do i paralell and aircool the hotside?

That is the question im asking.

And lets assume i end up getting 5 x 226W tecs. i know im never going to run them at full blast, so what PSU should i be looking at?

The meanwell S600-12?

You need to be more specific about which TECs you are using. Running the 437's at 12V, you will draw about 12A per TEC. That's one big bunch of cooling - around 700W cooling power at 20C dT for all 5, at about 700W in. If you run those at 10V, you need 9A per TEC, 45A total, and get 550W cooling across 20C dT for 450W in. A Meanwell 600-12 would work for that setup.

Are you talking about the 12726 TEC offered on eBay as the '226W TEC'? If so, I would suggest running those at 5V. You will draw about 8.5A per TEC, and get about 60W cooling across 20C dT. So all 5 gives 300W cooling for about 220W in.

That would require a supply which can deliver 45A or so at 5V. Meanwell SP-320-5 has 55A so that would work.

[NaeKuh]

well im getting the stuff back from nol.

so my options are these at the moment.

1. Get 227 x 5 tec's and run them @ 5V and pray my meanwell S320-12 will hold out.

or.

2. Get my pal bei fei to make me matching base plates to those tec's, run them paralell and have 10 x 227W tecs on it.
however i think id need a second psu for the other side.

[Uncle Jimbo]

well im getting the stuff back from nol.

so my options are these at the moment.

1. Get 227 x 5 tec's and run them @ 5V and pray my meanwell S320-12 will hold out.

or.

2. Get my pal bei fei to make me matching base plates to those tec's, run them paralell and have 10 x 227W tecs on it.
however i think id need a second psu for the other side.

Here's a better option - get 4 12730 TECs (the eBay '545W' Ebay 545 HERE ) and wire them as 2 series pairs. They will draw about 10A at 6V, so your Meanwell will easily deliver the total of 20A at 12V.

At that level, each TEC will provide about 80W of cooling at 20C dT, for a total of 320W cooling. Power in is only 240W. This setup is also self-regulating to some extent - at lower heat load (say idle or normal use) the dT will not run up that much, because when below 35% Imax, the higher dT curves don't move much power. You will also have good headroom - the cooling at 10C dT is 120W per TEC, for a total of 480W. So you won't 'hit the wall' if power goes up - you will just get a little less cooling.

[NaeKuh]

okey as soon as i get my chiller back i will run those tec's.

i also intend to use 2 400mm res, for volumn.

And i am looking at getting a dweyr t-stat.

[zoson]

Hi Guys...
Why add a whole second loop?


Found this online and it seems like with the principles explained in this thread... You don't need a large element cooling your tec because the rad will be helping dissipate the heat...

[zipdogso]

The post rad theory and every other theory with a rad in the loop with a TEC is flawed.

You see a rad will only chill to ambient then it starts to heat the water up - it doesnt matter whether it's before the TEC or after - as soon as the TEC starts to take the coolant below ambient the rad will try and warm it up again.

The whole point of using TEC's is to get the temp low - why add something to the loop that will have the opposite effect ? Doesn't make sense....

EDIT - OH Lord....I have just re-read your post. The other problem theory is one of only having one loop and passing by both sides of the TEC....Is that that your refering to ? Your asking what's the point of the second loop ?

Well...TEC's aren't chillers per se they are heat pumps moving heat from one point to another - AND THAT IS ALL THEY DO - if you have the loop passing both sides you just remove the heat at one point via the coldside and plonk it back into your loop some place else via the hotside - in short you don't cool the loop at all.

For efficient TEC operation you use the coldside to remove the heat from your coolant,copper block etc. etc. and then either use a second loop to remove the heat using a rad or instead, if the heatload of the hotside will allow, you can use a fan/heatsink assembly. To use a fan/heatsink to cool the hotside you will need to be using either a low (70w) TEC at fairly high power or a heavily undervolted large TEC....The other possible solution would be to use a heatpipe to ferry the heat to a more suitable site for cooling...and those methods my friend, are the only sensible ways to do it.

[Ultrasonic2]

Oh not this single loop rubbish again.

[NaeKuh]

Oh not this single loop rubbish again.

...

Yeah this was scraped later on.. and was decided to run the tec's by themselves..

Originally it was to use the rad as a safety net on the cold side so i wouldn't dip too low into sub ambient.

Later on i changed the plans so i would just control how hot the hotside got with a controller, and by that i could control the cold side.

[zipdogso]

Naekuh...how's your 4 TEC block coming....or have I missed it somehow ?

[NaeKuh]

Naekuh...how's your 4 TEC block coming....or have I missed it somehow ?

i should hopefully get them back from skinnee soon.

After that im rebuilding my entire system into nadeshiko with a TMP-200 as the controller.

Meh... i might need another pedistol to support the TEC stuff, or i might just have bei make me a case to house the meanwell, 2 x mcr320's for the hotside + a typhoon bay res.

[zoson]

Man, you all need to work on your reading comprehension, not to mention picture comprehension.
The hot side would be cooled via heatsink(seriously, did you even look at the pictures?). Not water, so it wouldn't be dumping the pumped heat into my water loop. It would be dumping it into the air.

The idea is that my heating elements dump say 300W of heat into my loop. My radiators dissipate about 300W of heat at a delta of about 7C. So if I add a cold side of a peltier moving even 50W of heat out of my water onto a heatsink.

And the whole POINT of doing it like this is so that you _CAN NOT_ get below ambient, and insulation would be unnecessary. Efficiency be damned. I'm just trying to control my coolant temp a little more, and I've run out of space inside my case for radiators, but I *could* fit an 80mm device like this.

[flak-spammer]

Well your idea probably won't work as well as you think. Lets say you wanted a low-ish watt TEC, So I'd say maybe a 12706 so that would be a Qmax of about 50w at 12v, Only problem is that's also about 45-50w of heat dumped with no load. Okay so air cooling doesn't tend to be so effective when cooling high loads so you wanted to dissipate 50w that's about the max that TEC could handle. So you'd end up with a dt of 0 and 100w to dissipate with that heatsink. Lets say room temp was 20C and the heatsink/fan was 0.3C/w so that's 30C over room temp or a cold side temp of 50C. You arn't going to be doing any cooling with that. See the problem now?

[zoson]

Well your idea probably won't work as well as you think. Lets say you wanted a low-ish watt TEC, So I'd say maybe a 12706 so that would be a Qmax of about 50w at 12v, Only problem is that's also about 45-50w of heat dumped with no load. Okay so air cooling doesn't tend to be so effective when cooling high loads so you wanted to dissipate 50w that's about the max that TEC could handle. So you'd end up with a dt of 0 and 100w to dissipate with that heatsink. Lets say room temp was 20C and the heatsink/fan was 0.3C/w so that's 30C over room temp or a cold side temp of 50C. You arn't going to be doing any cooling with that. See the problem now?

Finally, a real answer. Thank you very much for clarifying it for me flak-spammer.
So the moral of the story is the hot side would either require a jet engine fan cooling it, or it would have to be a lot bigger than the guy used as shown for his aquarium(the mcx462 does in fact have a c/w of .29 with a reasonably quiet fan).

[zipdogso]

Man, you all need to work on your reading comprehension, not to mention picture comprehension.

2 pictures that really was not clear what it was about ( 1 showed a TEC/heatsink with 2 tubes going to it - water cooling perhaps !!! the other just showed the same unit in situ.) and 40 words which weren'nt particularly clear either...you know what you were talking about but did'nt clarify it to anyone else. A link to the thread you were referring to would of been nice...But on the face of it since your query had nothing to do with this thread you should of started a new one - and clarified yourself a bit better - we aren't flipping mind readers....

Finally, a real answer. Thank you very much for clarifying it for me flak-spammer.

Yes...now you have given up a given us a clear indication of your thoughts...

well done FLAK...

To do what you thought but it still wouldnt be great... you would need to use a large TEC undervolted - this would give you a Dt at 50w which would get you a small measure of cooling but you would still have 100w maybe a bit more coming off the hotside - roughly one can always assume the heat coming off the hotside will be 2 to 2.25 times the cooling on the coldside. It is pretty tricky to cool any TEC of a size worth using with a passive heatsink but on that point a fan will AWAYS greatly improve things.

[Ultrasonic2]

To do what you thought but it still wouldnt be great... you would need to use a large TEC undervolted - this would give you a Dt at 50w which would get you a small measure of cooling but you would still have 100w maybe a bit more coming off the hotside - roughly one can always assume the heat coming off the hotside will be 2 to 2.25 times the cooling on the coldside. It is pretty tricky to cool any TEC of a size worth using with a passive heatsink but on that point a fan will AWAYS greatly improve things.

it's a pretty small heat sink too

[zoson]

2 pictures that really was not clear what it was about ( 1 showed a TEC/heatsink with 2 tubes going to it - water cooling perhaps !!! the other just showed the same unit in situ.) and 40 words which weren'nt particularly clear either...you know what you were talking about but did'nt clarify it to anyone else. A link to the thread you were referring to would of been nice...But on the face of it since your query had nothing to do with this thread you should of started a new one - and clarified yourself a bit better - we aren't flipping mind readers....



Yes...now you have given up a given us a clear indication of your thoughts...

well done FLAK...

To do what you thought but it still wouldnt be great... you would need to use a large TEC undervolted - this would give you a Dt at 50w which would get you a small measure of cooling but you would still have 100w maybe a bit more coming off the hotside - roughly one can always assume the heat coming off the hotside will be 2 to 2.25 times the cooling on the coldside. It is pretty tricky to cool any TEC of a size worth using with a passive heatsink but on that point a fan will AWAYS greatly improve things.

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

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)?

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

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

[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.