Voltage Regulator 12v 20amp based on temperature

Thread Starter

agres

Joined Aug 14, 2019
4
Hi everyone!

I hope I'm not repeating another thread (I searched) and that my idea is not too exotic.

I want to install a thermoelectric element in my water cooled pc with 2 processors. My power supply is powerful enough to handle 2 x TEC1 12706 12V 6A.

The problem is that if I will run them at full power I will encounter following problems:
1. The TEC will start to heat up itself if run at full power.
2. At optimal power of 50% it will cool the processors below ~15 degrees (might easily reach minus) which will create condensate.
3. Power consumption is unnecessary and it is too much cooling.

So I have the following goal:
The controller should operate the voltage in a such a way to keep the temperature ~20 degrees. When temperature goes up - the voltage goes slightly up so to keep the temperature within limits.

The idea with relay its not sexy due to constant ticking of the relay which will be annoying.

I'm not much advanced in electronics, but to pick up components and assemble I will manage!

Big thanks in advance to anybody involved in solving my problem!
 

AnalogKid

Joined Aug 1, 2013
8,101
The obvious solution is to use smaller TECs.

Beyond that, there are four ways to go:

1. A switching regulator to step down the operating voltage without generating a ton of extra heat, varying the output voltage inversely with temperature.

2. A pulse-width modulation (PWM) circuit to vary the total energy to the TEC while producing even less excess heat than a switching regulator.

3. A bpulse-position (PPM) controller that switches the TEC from full on to full off at a very slow rate, such as on for 5 sec and off a variable amount of time depending on the temperature.

4. An all-electronic thermostat like the relay system you describe but with a transistor as the power switch for silent operation.

ak
 

Thread Starter

agres

Joined Aug 14, 2019
4
I believe option 2, a PWM will work best for me. Can you help me with that please?
 

AnalogKid

Joined Aug 1, 2013
8,101
Before getting into circuits. seriously consider a mechanical thermostat, such as a klixon or snap disc. It is a mechanical switch, but very silent. No adjustments, you buy one with the trip point and hysteresis you need. Very simple, with excellent long-term reliability.

ak
 

Thread Starter

agres

Joined Aug 14, 2019
4
Thank you very much! You are genius! This should do the job. One tiny thing remained. I would like to limit the max power to the TEC so it would work on 50%. Do you know an elegant solution like this one? :)
 

dendad

Joined Feb 20, 2016
2,986
PWM is the easiest way to go to limit the max power. An Arduino driving a good sized logic level FET is what I would use. Then you can have a thermistor or some other temperature sensor read by the Arduino, and add an LCD to tell you what is the status.
This could be a good starter project if you have not played with Arduinos before.

Here is just one example to modify from a quick search...
https://www.nutsvolts.com/magazine/article/arduino-pid-temperature-control
 

MisterBill2

Joined Jan 23, 2018
3,861
Another really simple option that will also avoid any condensation issues is to allow some temperature rise, and then select a TE cooling device rated to remove the heat based on the wattage spent in the dual processors. The result would be no on/off control needed, since the system can run all the time.
 

Thread Starter

agres

Joined Aug 14, 2019
4
Another really simple option that will also avoid any condensation issues is to allow some temperature rise, and then select a TE cooling device rated to remove the heat based on the wattage spent in the dual processors. The result would be no on/off control needed, since the system can run all the time.
In this case I just don't need the TEC at all. The water cooling can handle the heat and not allow my processors go over 80 degrees celsius.

So far the snap disc option is the best. I will prepare the setup and maybe will share the progress and some pics here.
 

MrChips

Joined Oct 2, 2009
19,270
Maybe all you need is a cooling fan.
If you wish to go below ambient temperature then a TEC will work but you still need the cooling fan to cool the TEC.
To control the TEC temperature you can read up about PID controller.
P (proportional) control alone will do the trick.
 

Wolframore

Joined Jan 21, 2019
1,251
We like new tech and explored TEC but the amount of power consumed (heat) and having to run cooling to cool the TEC didn’t make sense in terms of efficiency. The one we looked at was a 40 watt version. Am I missing something? Is the cooling on the chip worth this expenditure?
 

MisterBill2

Joined Jan 23, 2018
3,861
We like new tech and explored TEC but the amount of power consumed (heat) and having to run cooling to cool the TEC didn’t make sense in terms of efficiency. The one we looked at was a 40 watt version. Am I missing something? Is the cooling on the chip worth this expenditure?
This is true, ALL of the electrical power fed to the TE cooler must also be rejected as heat. Thus the cost of such a heat moving device is not small.That same TE device must have power provided by a supply that also produces heat. Thus it may be that the very best investment is in a better heat sink and a fan. Of course those are not nearly as sexy as a water cooling system, but a good heat sink is a very reliable thing.
 
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