PID Controlled Peltier Heating and Cooling

ElectricSpidey

Joined Dec 2, 2017
2,027
Thanks for posting the air flow diagram.

It looks like the hot side is a bit larger than the cold side...is this true?

If it is true the concept will work, but I would take the difference into consideration when powering it in heat mode.

Good luck, it's a pretty cool project.
 

Thread Starter

JesusLopez

Joined Jun 1, 2021
22
Thanks for posting the air flow diagram.

It looks like the hot side is a bit larger than the cold side...is this true?

If it is true the concept will work, but I would take the difference into consideration when powering it in heat mode.

Good luck, it's a pretty cool project.

Yes, that's correct. Any advice on wiring it up correctly?
 

Thread Starter

JesusLopez

Joined Jun 1, 2021
22
So after nearly giving up. I finally figured out the most important step. The rest should be mostly simple.

I was able to reverse the TEC modules polarity proving I can in fact make this unit cool and heat. I'll be updating here as I make progress.

I've attached an updated diagram for my full build.

So far so good!
 

Attachments

I played with TEC modules at work in various modes. Surface and air in a chamber.

One was a Cambion linea controller with a ground water sink. Temperature controlled by a bridge/thermister.

others were fan cooled on the other side.

Then there was the home made "cabinet cooler" Fan on outside, fan on inside.

remember delta T (about 60C) melts the TEC.

Never used PWM, but it works, but it's not the best way. Current controlled is best.
Did the power supply only method.

I don;t know exactly how your controller will behave, but some of the cheap ones don;t have 0-10V or 0-20 mA output which is 0-100% or how it does heat and cool. Usually, you have a heat output and a cool output and sometimes a mode available.
Mode is what you would like. An analog deviation output can be converted to mode.

You would neeed to convert the 0-10V signals to PWM and select the mode.

e.g.
if out1> 0.1% then cool
if out1> 0.1% then heat
if out1 < 0.1% and out2 <0.1% stay in last mode.

Or use the deviation output to select the mode.


Usually we had a large lamp load 1200 W shining from 3' or so with some frosted glass and alignment method. Lamp had dichroic reflectors, so the IR went out the back of the lamp.

The largest one was 12V, a plate with a fan and heatsink on the other side.

The H-bridge should work. PID will probably be tough to get working because of the really high thermal mass.

The one that had the most temperature control was a microscope stage. Ground water sink. Usually 25C control. There was an independent thermometer (thermister) and a thermister to the controller.
The controller was linear and had a turns-counting dial for the setpoint.

Watch the dew point. Water may end up in places unintended.
 
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Thread Starter

JesusLopez

Joined Jun 1, 2021
22
So this is where i am so far. i have just about everything working all off of one power supply.

The TEC modules are fully controlled by the PID to heat and to cool. Its pretty exciting to finally see it come together. And work the way i knew it would.

All that's really left to do is clean it all up and do the final wiring. then pack it all nicely in a metal housing.



PXL_20210615_000435643.MP.jpgPXL_20210615_000430007.MP.jpgPXL_20210615_000444983.MP.jpgPXL_20210615_000452998.MP.jpgPXL_20210618_184042196.MP.jpgPXL_20210618_200428061.MP.jpg
 

Thread Starter

JesusLopez

Joined Jun 1, 2021
22
Well I'm finally done with the electrical part of this project. Check it out!
About as custom made as it gets.

Humidor control system:
Humidifier
Germicidal Light
LEDs remote controlled and dimmable
Heating and cooling reversible all in one with TEC modules
Fan speed controller for all internal fans
Custom CNC'ed brass controls board
All ran off of one power supply with one switch on/off

Video Walk-through Link:
https://photos.app.goo.gl/EpnaGCjwnpc4N3KG9



PXL_20210722_193027295.MP.jpg
 

jiggermole

Joined Jul 29, 2016
50
Almost looks like you know what you're doing :)

Looks great for all the stuff you had to shoehorn in there. The cable management ocd monkey is having a bit of a fit but thats about all.
 

Thread Starter

JesusLopez

Joined Jun 1, 2021
22
Almost looks like you know what you're doing :)

Looks great for all the stuff you had to shoehorn in there. The cable management ocd monkey is having a bit of a fit but thats about all.
Lol, yeah I could of easily spent another 2 months on this part of the project but I had to eventually move on.

I can finally work on the woodworking part, which I'm most excited about.
 

RobNevada

Joined Jul 29, 2019
66
I would use a reversing relay to control power to control whether you have heat or cooling An example would be no power to the relay coil would be cooling and power the coil and heat would be the output. You would use a Dpdt relay
 

Thread Starter

JesusLopez

Joined Jun 1, 2021
22
I would use a reversing relay to control power to control whether you have heat or cooling An example would be no power to the relay coil would be cooling and power the coil and heat would be the output. You would use a Dpdt relay
I appreciate it, I tried that with my second attempt but I wanted something more automated. I've been able to successfully control the heating and cooling by controlling the TEC Modules DC polarity with a PID connected to SSR's, works beautifully.
 

Thread Starter

JesusLopez

Joined Jun 1, 2021
22
That front panel is very nice looking, did you make that?
Thanks! Yeah I designed it in illustrator and made the CNC tool paths in vectric then milled it out of a brass plate with a shapeoko CNC. Then aged it, then polished it. Bought the knobs and switches online.
 

strantor

Joined Oct 3, 2010
5,752
Wish I would have seen this thread back in June...

What's the application? Maybe I skimmed past it but all I saw was "a cabinet" but this seems something more.

I did a bit of research into these Peltier coolers for electrical enclosures (that's what this was originally, right?) and decided that they suck compared to conventional refrigerant cycle air conditioners for electrical enclosures, for the application of cooling an electrical enclosure. A big part of that is because they don't do anything to dry the air or handle condensate. You know all that water that drips out of a window unit? Well that water would be dripping inside the electrical enclosure (assuming the Peltier could even manage to appreciably cool the enclosure, which it couldn't without installing several of them).

So I'm curious what kind of application this is, and what kind of results you get. Is condensation a problem? I would like to know if I made a bad first judgment.
 

Thread Starter

JesusLopez

Joined Jun 1, 2021
22
Wish I would have seen this thread back in June...

What's the application? Maybe I skimmed past it but all I saw was "a cabinet" but this seems something more.

I did a bit of research into these Peltier coolers for electrical enclosures (that's what this was originally, right?) and decided that they suck compared to conventional refrigerant cycle air conditioners for electrical enclosures, for the application of cooling an electrical enclosure. A big part of that is because they don't do anything to dry the air or handle condensate. You know all that water that drips out of a window unit? Well that water would be dripping inside the electrical enclosure (assuming the Peltier could even manage to appreciably cool the enclosure, which it couldn't without installing several of them).

So I'm curious what kind of application this is, and what kind of results you get. Is condensation a problem? I would like to know if I made a bad first judgment.

Here is a very rough 3d mock up of what the cabinet will be. Its a cigar humidor that will require high humidity and mild temperature control +-10 degrees since it will be indoors but in a poorly insulated part of the home. Made out of solid Spanish cedar.

The control board will be placed high at the top of the cabinet and the heating /cooling unit mounted to the center back of the cabinet. And the PSU will be mounted to the bottom on the outside of the cabinet.

I don't expect the heating and cooling unit to really even be needed until the harshest days of mid winter and mid summer. just to assist in leveling out the temperature.

Also i will be installing drip pans on both sides of the cooling/ heating unit to prevent any drippings from dropping down.

Video:. https://photos.app.goo.gl/HZ99RQc3KeinxFF1A

there will be integrated.
Cigar Humidifier
Germicidal Light
LEDs remote controlled and dimmable
Heating and cooling reversible all in one with TEC modules
Fan speed controller for all internal fans


Capture1.JPGCapture2.JPGCapture3.JPG
 
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