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Discussion Starter #1
Hello everyone, i am new to this forum and a bit hesitating to share my experiences with TEC modules.
But hey, why the hell not!!!
It may look very crude and messy, but it was back in 2007 and had to build it from scratch, many valuable lessons learned from it, that's for sure.
Back in 2007 i built a system with a double loop cooling circuit, the idea was to integrate everything in a separate case, even that i made myself which turned out to be a big mistake, acrylic panels are not easy to work with.
What i built was based on harddrive cooling blocks with the peltier elements sandwiched in between as shown on the photo.

The copper/plex blocks i got from Caseking.de in Germany, with Eheim pumps.
The pelts were 15.4 Volt 6 Amp modules, each capable of tranferring 56 watts of heat if i remember correctly.
I used 2 peltiers on each side of the all copper block, so 4 peltiers in total, hot side chilled by the copper/plex blocks on the outsides.
Power supply i built myself, just a very crude simple one with a temperature controller of Velleman, simple on/off relay thing nothing fancy.

It was a proof of concept and it worked.
I was able to get it down to 1.2 degrees C and ofcourse got into condensation troubles.
Just wanted to share this, as i feel i was a bit of a pioneer, with many others who have the same ideas ofcourse.
Thinking now of a radical rebuild, with the aim to reduce costs.
Still thinking a lot on how to improve the initial concept, with technology that improved so much in those 10 years.

The processor back then was a Pentium 4 at 2.6GHz and chilled down it was overclocked to 3.4GHz and running stable.
As you can see in the photo i was using a toroidal transformer rated at 2x12V/12.5Amps, because i supplied the pelts with only 12 volts instead of 15.4 it ran at about 80% capacity, giving about 160 watts of cooling capacity.
It was crude i know, but for me it was just a proof of concept.
Now i would build it much simpler, more powerful.
Currently thinking of something in the order of 450 or 600 watt cooling capacity.
Who knows, maybe in the near future.

Cheers and keep it up.

Johannes
 

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cool, nice job with the build, don't worry about the looks of it. this is extreme cooling, it's about performance, not looks. all of my builds look awful, it does not prevent me from building them at all.
thumb.gif
 

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Discussion Starter #5
Thank you Master Chicken, i build it 10 years ago....
Now thinking of a setup in which i use 15, 16 peltiers in series supplying it with 230 VDC with a PWM motor controller and a fat capacitor to straighten out the ripples/pulses.
But here on this forum i read that such a solution is less desirable.
Maybe some of you guys can explain the reason why this is not such a good idea.
The heat exchangers will be similar to what i used previously, only slightly larger in size, probably custom made on a metal mill to fit 15 (5x3) 30x30mm peltier elements.
Just thinking things over at the moment.
 

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Quote:
Originally Posted by JohannesS View Post

Thank you Master Chicken, i build it 10 years ago....
Now thinking of a setup in which i use 15, 16 peltiers in series supplying it with 230 VDC with a PWM motor controller and a fat capacitor to straighten out the ripples/pulses.
But here on this forum i read that such a solution is less desirable.
Maybe some of you guys can explain the reason why this is not such a good idea.
.
I don't really get it myself??? I think it may be because of the added amount of electricity needed to power the PWM circuit???? regardless that is how I am controlling my TEC's (minus the Caps) I would be interested in seeing what type of caps will work, as TEC's use a lot of amps.
tongue.gif


simple PWM motor controllers, or small ones, seem to burn up rather quick, at least mine did. I had a 15amp PWM motor controller that lasted 3 days at 10amps, my 25 amp PWM motor controller lasted about 3 months at 18amps. now I use 100amp PWM motor controllers at 30amps, and have not had a issue as of yet. (just over 3 months of use so far)
 

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Discussion Starter #7
Mmm i am thinking of ordering a chinese controller.
Not sure if it is allowed to paste a link here, but let's find out...

https://www.aliexpress.com/item/1-5kw-220v-DC-motor-speed-regulator-governor-High-power-treadmill-or-110v-motor-controller-Infinitely/32709410363.html

It can handle up to 10 amps, i use only 1/3 of that capacity.

Peltiers are TES1-12703 rated at 3,2 amps and 30 watts at 15,4 volts, 15 of those suckers in series kicks up the voltage to around 230 VDC and the amp rate remains the same.

http://www.peltiermodules.com/?p=product

Total combined cooling power is 450 watts and option to kick it up to 600 watts using the 40 watt types TES1-12704.

What i understood is that the pelts dont seem to like the pulses from a PWM power supply, things about degrading them etc... thats why i would add a caps to straighten the ripple current.

Thing i like about peltiers is that they suck out the heat and dump it into the watercooling circuit
 

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that is a big build.

yes, 15 TEC's in series at about 15 volts each, is 230volts DC. that will also be at 3 amps for each TEC so 45 amps total for that circuit .
wink.gif

it's the amps that are the hard part to deal with electronically, I have upgraded the electronics on my own build 3 times now, so that the circuit could handle the amperage.

here is the simple circuit I am using to control my TEC's.

https://imgur.com/a/L9Ky3



it is not a cheap circuit, but it is functional. power supply to the relay, the relay is controlled by the switch, relay goes to the PWM controller, and then from the PWM controller to the two TEC's.

power supply for two TEC's, will run about $100, the relay is $75, the switch is $10, the PWM controller is $70, and two TEC's are $120. so, for me, just to power two TEC's, cost me about $375.
 

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Discussion Starter #9
Toolmaker,

With Ohm's law in mind (P=UxI), you only multiply the voltage 15x, the current for the circuit remains at 3.2 amps.
If you put them in parallel you are right, but then the voltage remains at 15.4 volts and the amps get multiplied by 15.
The power output is key, the watts consumed are equal in series or parallel, ohm's law dictates that by P=UxI. (P is power in watts, U is Voltage, I is current in Amperes.

Now each module has 30 watts heat transfer capability, but 15.4x3.2=49,3 watts consumed by each module (you can also calculate the efficiency now).
That multiplied by the number of modules is 739.2 watts consumed power and a heat transfer of 450 watts.
In series you get U=15,4V multiplied by 15 = 231 Volts, amps (I) remain at 3.2, but 231V multiplied by 3.2A gives P=739.2 watts
In parallel the voltage remains at 15.4V but the amps get multiplied by 15 equaling to 48A, giving 739.2 watts too!!!
It's late here, i go to bed but i hope you see how it works with Ohm's law in mind.
Cheers bro, nice to meet likeminded people on here.

Talk soon
 

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you are absolutely right, I was looking at the individual component amp draw and voltage through each TEC. the total circuit would be the 3.2amps at 231volts. I have never tried anything like this, the theory is sound, and the hardware should handle it. the most I have tried is three TEC's in series on a 24volt power supply. it will be cool to see this working.

just in case that control board does not work quite as well as it says it should.

https://www.amazon.com/TekPower-TP50SW-Analog-Supply-Cigarette/dp/B00L5QU616/ref=sr_1_95?ie=UTF8&qid=1511208039&sr=8-95&keywords=adjustable+dc+power+supply

this 15volt 50amp power supply is just big enough to handle this build, I would actually suggest getting two of them.

don't misunderstand me, I would love to see this build functional for the cost of a 230volt plug wire and a $50 control board. I just think that board will pop the moment it goes active. this is just my honest opinion here.

https://www.amazon.com/Supply-Adjustable-Current-Limiting-CSI12003X/dp/B00FY3KZ7G

I did find a 120 volt 3amp power supply, for $284. I could not find any 220 volt DC power supplies.
 

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Discussion Starter #11
Currently staying in Slovakia and it is quite a daunting task to source everything, the first option you give cannot be delivered here.
But chinese motor controller is just a first step, i want it controlled by an Arduino with a digital potentiometer output which will serve as input for the motor controller.
It will take time to get it all delivered, if i plan to go ahead with it.
It is quite a costly affair.
 

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Discussion Starter #18
Here are some additional pics:
From the cooling block, consisting out of full copper block in the middle and two copper/plex blocks on the outsides.



This pic shows the other side, with the 2x240mm radiators and 4 fans, this was used to cool the peltiers hot sides.



This pic show the toroidal transformer going from 230VAC to 2x12Volts/12.5 Amps, so it had double output.
To this i had 4 peltiers, model TEC1-12706 in parallel twin setup per side on the copper block and 2 per output on the transformer.



The transformer was switched by the temperature controller, the double output was going to a set of diode bridges with capacitors behind it to take care of ripples in the current, basically i calculated R/C time for pelt load and capacitor and multiplied by 5 which is the rule of thumb for ripple currents.
From the capacitors the power was going to the peltier elements, 2 separate circuits with 2 peltiers parallel with each other, 4 peltiers in total.
The small fan under the controller was cooling the print containing the diode bridges, remember it was two circuits utilizing the double output of the transformer, 2x12V/12.5 amps.



The copper Tee is holding the temperature measuring PTC element that was connected to a small tiny PCB that was part of the temperature controller, the controller was a kit i ordered and soldered together.



On this photo you see the readout on the controller at 1.6 degrees C, all the tubes not having insulated yet.

Lastly overclocking and benchmarking pics. the top bars in the benchmarking pic was my system, it performed very well.


 

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Discussion Starter #19
The rebuild i am thinking of now, is probably going to be in a Corsair Obsidian 900 series case, plenty of space available, price around 300 euros.
The computer hardware i have no idea about yet, but the goal is to cool both the CPU and the GPU.

1500Watts motor controller from China, where the potentiometer will be replaced with an Arduino digital potentiometer, in that way i can fully automate the controls.
The ultimate goal is to have a neat TFT touchscreen to operate it and change settings etcetera.

Heat exchanger will be two blocks of aluminium or copper with cooling canals milled into it, closing it with a cover plate and a gasket to seal it ofcourse.
Dimensions of the individual peltiers is 30x30mm, in an array of 5x3 so i need to have a surface of 150x90mm at least.
Colleague of mine will have his CNC machine up and running by January, so then it is showtime i hope.

In the meantime in China i order the 15 peltier elements TES1-12703 of 30 Watts each (cooling capacity) drawing 3 amps at 15.4 Volts.
The idea is to put them in series, to get 15.4 x 15 is 231 Volts.
The whole string of peltiers are supplied from the motor controller, which has 230VAC input and up to 230VDC output, it will have a capacitor to take out the worst ripples.
In total i get 450 Watts of cooling capacity and the option to apply TES1-12704 of 40 Watts to kick up the cooling capacity to 600 Watts if wanted.
With adaption of the heat exchanger i can go up to 12708 if i want which have over 80 Watts cooling capacity each, that would deliver 1200 Watts of cooling capacity, but i dont need it.

The radiators, fans and pumps/reservoirs probably will be sourced in Germany (Caseking.de) but those are just standard items, nothing special.

Probably i order 2 sets of peltiers TES1-12703 and TES1-12704, they are less then $5 each.
The controller is $50, the Arduino i can order locally for around 50 euro.
But i am just thinking it all over at the moment.
All in all i wish to keep the budget under 1000 euro for the cooling itself, excluding the pc hardware which can be as expensive or cheap as desired ofcourse.
 

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Discussion Starter #20
One last addition i am thinking of is to deal with condensation issues.
Currently thinking of nitrogen purging, but it means i have to create an airtight box inside the pc case that holds the mainboard and the cold plate of the heatexchanger.
Any ideas on how to construct such an airtight box are very welcome.
It does not need to be completely airtight, just maintaining slight overpressure inside the box is enough.
 
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