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Peltier chilling system - Page 4

post #31 of 167
Thread Starter 
Quote:
Originally Posted by LiamG6 View Post

for your setup I'd use 12715's and run them in sets of 2 wired in series so they get about 6v each, same Qc wattage at 20*c delta as you have now, but half the power usage from TEC's, half the power means half the heat dump from the tec, so hot side water is cooler, so your hot side of TEC will be cooler, which means you'll see more of your delta below ambient rather than wasting it on the hot side temps above ambient.

Once you add a heat load to your current setup you'll get about half the delta you currently are, which is why I suggested 12715's as you'll get the same or greater delta but with literally half the power usage. ie 12708's at 12v x 6amps x 4 tec's = 288watts or 12715's at 6v 6a x 4 tecs = 144watts. Each setup has approximately 160w of Qc at 20*c delta below ambient. 12708's have COP of ~.55, 12715's have COP of 1.1, twice as efficient for the same or better temp drop.


Very interesting and informative! I'll have to snag a few 12715's and give that a shot!


toolmaker -

I'm running G13.

You probably didn't test this one as you wont find it at any standard automotive store. It's a VW/Audi specific coolant and its expensive as ****! I happen to own an audi S4 so i have a bunch of the stuff laying around. It's pretty good at anti-corrosion, most of their engines are all aluminum.
post #32 of 167
if you do grab the 12715's, get 8, as it will be a very very good chiller with 8 of them at 6v when you get around to revision B of your chiller, although with 8, you may need to start looking into PWM or DC control to stop them getting too cold when your CPU or whatever you are cooling is idle.

Also with the primitive water blocks you are using, keeping the power density as low as possible is very important, ie more tecs and blocks as you plan, spreads the heat load out allowing the primitive water block to handle the heat load without rising in temp very much. The efficiency of a water block is measured in degrees celcius / watt temperature rise, ie for a given amount of watts being transferred through the water block the temperature of the copper surface that is contacting the tec will rise a certain amount above the water temperature that is being circulated through the block. Those blocks will have quite a high *c/w temp rise so it is important to keep your heat density as low as possible by using more TEC's and more water blocks and using TEC's that are as efficient as possible, thats why 12715's will be a big improvement, by halving the heat load from the TEC itself and avoiding wasting your delta t on hot side loss above ambient.

Also, you have the cold sides of 2 TEC's on 1 block, it takes longer to chill the water down to a certain temp than it does to pull the heat away above ambient, so the longer the water in the cold side spends in the block the better, so yes, keep them in series as you have, but ideally use 1 cold side block per tec, in order to keep the water circulating through the cold side chillers as long as possible per circulation. having 2 cold sides on 1 block will not lower the temperature of the block further than the delta t of each tec, so it is better to just use 1 tec per cold side block. It is totally fine as you have it, but if you have the money and the space and the blocks aren't too restrictive I would use 8 hot side blocks with maybe 4 x 2 in parallel, and 8 cold side blocks in series.

also look into some norprene tubing for your cold side loop, and get some armaflex pipe insulation too.

great project, hope you are having fun and learning a lot, TEC's are a really interesting way to cool PC's. Can be very cheap and effective.
Edited by LiamG6 - 7/5/16 at 9:31pm
post #33 of 167
Thread Starter 
Quote:
Originally Posted by LiamG6 View Post

if you do grab the 12715's, get 8, as it will be a very very good chiller with 8 of them at 6v when you get around to revision B of your chiller, although with 8, you may need to start looking into PWM or DC control to stop them getting too cold when your CPU or whatever you are cooling is idle.

Also with the primitive water blocks you are using, keeping the power density as low as possible is very important, ie more tecs and blocks as you plan, spreads the heat load out allowing the primitive water block to handle the heat load without rising in temp very much. The efficiency of a water block is measured in degrees celcius / watt temperature rise, ie for a given amount of watts being transferred through the water block the temperature of the copper surface that is contacting the tec will rise a certain amount above the water temperature that is being circulated through the block. Those blocks will have quite a high *c/w temp rise so it is important to keep your heat density as low as possible by using more TEC's and more water blocks and using TEC's that are as efficient as possible, thats why 12715's will be a big improvement, by halving the heat load from the TEC itself and avoiding wasting your delta t on hot side loss above ambient.

Also, you have the cold sides of 2 TEC's on 1 block, it takes longer to chill the water down to a certain temp than it does to pull the heat away above ambient, so the longer the water in the cold side spends in the block the better, so yes, keep them in series as you have, but ideally use 1 cold side block per tec, in order to keep the water circulating through the cold side chillers as long as possible per circulation. having 2 cold sides on 1 block will not lower the temperature of the block further than the delta t of each tec, so it is better to just use 1 tec per cold side block. It is totally fine as you have it, but if you have the money and the space and the blocks aren't too restrictive I would use 8 hot side blocks with maybe 4 x 2 in parallel, and 8 cold side blocks in series.

also look into some norprene tubing for your cold side loop, and get some armaflex pipe insulation too.

great project, hope you are having fun and learning a lot, TEC's are a really interesting way to cool PC's. Can be very cheap and effective.


Thanks again man! Super informative!


All in all what you see in my pictures is roughly half the total project. I have a total of 12 water blocks and 8 tec's currently. The LCD interface you see is a simple arduino program i wrote, driven by an arduino mega 2560. The mega has the ability to do PWM and in conjunction with my temp sensors, i could program some load configuration like you mentioned!

Good news as my 655 pump will be here today! Very eager to run that bad boy. I think i will run it on the cold side for now, as the submersible is working just fine for the hot side.

-LiamG6

I do want to try the 12715's in the config you recommended, it's just they have a 50mm footprint. So i wont be able to use the waterblocks i have. I'll need to machine my own. This is only going to delay me from trying the 12715's but i do intend to do just that. Please don't take me continuing with experimenting on this current setup as not following your recommendation... its just going to be a bit before i can get into a machine to make the blocks. So i should stop the 2 cold sides feeding a hot side? I can see how this will create more surface area for heat transfer. I drew up a water block based on the 40mm footprint since i cant seem to find anyone who really makes a decent one. Ill have to revise this design for the new 50mm footprint of the 12715's. I designed it much like how ive seen other larger tec water blocks. It would have a center feed inlet, with dual outlets on the outside. Ill attach a pic. I could use this for the cold side and the hot side.
post #34 of 167
12715's are 40x40mm

http://www.ebay.com.au/itm/5PCS-TEC1-12715-Heatsink-Thermoelectric-Cooler-Cooling-Peltier-Plate-Module-SF-/191736124880?hash=item2ca45d15d0:g:--MAAOSwNyFWg1Tm

custom water blocks will be better if you can do it. that design looks fine. make them as big as possible though, being able to use them on 40-62mm TEC's would be ideal as there are some great 62mm TEC's. But for the sake of cost you can keep using your current water blocks with 40mm 12715s without any real issues. If you want to make custom water blocks I would use higher quality 62mm TEC's, and undervolt them to about 50%, ie 199xx TEC's are 24v, use them at 12v and they are fantastic

by all means keep experimenting however you want, it is only my advice that I wanted to offer you to get the most out of it, I don't expect anyone to do as I say.

honestly I would keep going in your current direction, keep your basic water blocks, stick to 40mm tecs, and if you want a little more out of it, get the 12715's. Once you start increasing the cost of TEC set up they become less satisfactory than if you can do it cheaply, all be it they can perform much better if you are prepared to spend a lot of money.
Edited by LiamG6 - 7/6/16 at 6:43am
post #35 of 167
Thread Starter 
Quote:
Originally Posted by LiamG6 View Post

12715's are 40x40mm

http://www.ebay.com.au/itm/5PCS-TEC1-12715-Heatsink-Thermoelectric-Cooler-Cooling-Peltier-Plate-Module-SF-/191736124880?hash=item2ca45d15d0:g:--MAAOSwNyFWg1Tm

custom water blocks will be better if you can do it. that design looks fine. make them as big as possible though, being able to use them on 40-62mm TEC's would be ideal as there are some great 62mm TEC's. But for the sake of cost you can keep using your current water blocks with 40mm 12715s without any real issues. If you want to make custom water blocks I would use higher quality 62mm TEC's, and undervolt them to about 50%, ie 199xx TEC's are 24v, use them at 12v and they are fantastic

by all means keep experimenting however you want, it is only my advice that I wanted to offer you to get the most out of it, I don't expect anyone to do as I say.

honestly I would keep going in your current direction, keep your basic water blocks, stick to 40mm tecs, and if you want a little more out of it, get the 12715's. Once you start increasing the cost of TEC set up they become less satisfactory than if you can do it cheaply, all be it they can perform much better if you are prepared to spend a lot of money.



Thanks for clarifying. I took my numbers off the first spec sheet i found. But every other spec sheet supports the 40mm x 40mm like you said. 62mm is also interesting! Had any experience with any of those?

p.s. I am in way deep with this project already. The peltier system is the cheapest part of all this. The arduino controller cost has exceeded my hardware cost haha.



http://www.thermonamic.com/TEC1-12715-English.PDF
post #36 of 167
Thread Starter 
Also i did snag a few buck converters... so i can control the voltage quite specifically below 12v.
post #37 of 167
Thread Starter 
ahhh if you look here

http://www.wellentech.com/specialTe.html


You can see they offer similar modules in a few different sizes. IE the 199xx for reference can be had in both 50mm and 62mm.

Specifically the TEC1-19915
post #38 of 167
this is so true I have a set of 3 X 12730's in the 50mm X 50mm size, normally they are 62mm X 62mm TEC's. it is hard to find high amp TEC's in the smaller sizes, if you could find a set of 12726's in the 40mm X 40mm that would be a great find, as they are normally 50mm X 50mm TEC's.
post #39 of 167
Thread Starter 
Quote:
Originally Posted by toolmaker03 View Post

this is so true I have a set of 3 X 12730's in the 50mm X 50mm size, normally they are 62mm X 62mm TEC's. it is hard to find high amp TEC's in the smaller sizes, if you could find a set of 12726's in the 40mm X 40mm that would be a great find, as they are normally 50mm X 50mm TEC's.

The most amperage iv'e seen for 40mm is the 12715 (15amps). And even then the manufacturers i was looking at only went to 10amps. Not until it was mentioned here in this post did i realize they even went up to the 15 in 40mm tongue.gif

My guess is you might cook a chip that small flowing 26 amps. The wiring alone wouldn't support that amperage, so its likely the couples can't either. With 4 tec's @ 12v i'm running around 24-amps and i'm powering it off 12ga wiring. That wiring gets pretty damn warm. Any warmer and i'd look at running parallel wiring to increase capacity.
post #40 of 167
Quote:
Originally Posted by mrkubanftw View Post

The most amperage iv'e seen for 40mm is the 12715 (15amps). And even then the manufacturers i was looking at only went to 10amps. Not until it was mentioned here in this post did i realize they even went up to the 15 in 40mm tongue.gif

My guess is you might cook a chip that small flowing 26 amps. The wiring alone wouldn't support that amperage, so its likely the couples can't either. With 4 tec's @ 12v i'm running around 24-amps and i'm powering it off 12ga wiring. That wiring gets pretty damn warm. Any warmer and i'd look at running parallel wiring to increase capacity.
Quote:
Originally Posted by mrkubanftw View Post

The most amperage iv'e seen for 40mm is the 12715 (15amps). And even then the manufacturers i was looking at only went to 10amps. Not until it was mentioned here in this post did i realize they even went up to the 15 in 40mm tongue.gif

My guess is you might cook a chip that small flowing 26 amps. The wiring alone wouldn't support that amperage, so its likely the couples can't either. With 4 tec's @ 12v i'm running around 24-amps and i'm powering it off 12ga wiring. That wiring gets pretty damn warm. Any warmer and i'd look at running parallel wiring to increase capacity.

yea, I can see that as being a definite issue, seeing as I am using 10AWG wire to power, my 12726's, and I had to shorten the 16AWG wires that are on the TEC's, down to 1", so that they would stop getting real hot.
but I am also running the TEC's at 13.57V and 23.1A steady, at start up there at 14.8V and 25.9A but they drop after a few min.
Edited by toolmaker03 - 7/6/16 at 12:06pm
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