how to vary the cooling temperature in the peltier module.?

Discussion in 'The Projects Forum' started by muthuaiyan, Aug 8, 2014.

1. muthuaiyan Thread Starter New Member

Aug 4, 2014
19
0
Dear friends,

how to vary the cooling temperature in the peltier module.?

can any current control circuit (or) voltage control circuit is used to vary the cooling temperature of the peltier module.

PELTIER module- TECH1-12706 Rating is Imax=6A,Vmax=15.4v

i have tried using the potentiometer(1kohm,1w) in parallel with peltier module and the input is 12v4.5Ah,what happen is when i vary the potentiometer the current decreases .83A the cooling temperature increases again i varied the potentiometer in opposite direction the current increases 1.5A the cooling temperature decreases.

I DON'T KNOW WHAT IS REASON..IF ANY ONE KNOW THE ACCURATE ANSWER
AND ALSO CIRCUIT FOR CONTROLLING THE TEMPERATURE ,REPLY ME FRIENDS..

--------I HAVE BEEN STUCK FOR PAST 1 WEEK----------------

If any circuit is available for controlling the temperature..suggest me if so

2. muthuaiyan Thread Starter New Member

Aug 4, 2014
19
0
Dear friends,

how to vary the cooling temperature in the peltier module.?

can any current control circuit (or) voltage control circuit is used to vary the cooling temperature of the peltier module.

PELTIER module- TECH1-12706 Rating is Imax=6A,Vmax=15.4v

i have tried using the potentiometer(1kohm,1w) in parallel with peltier module and the input is 12v4.5Ah,what happen is when i vary the potentiometer the current decreases .83A the cooling temperature increases again i varied the potentiometer in opposite direction the current increases 1.5A the cooling temperature decreases.

I DON'T KNOW WHAT IS REASON..IF ANY ONE KNOW THE ACCURATE ANSWER
AND ALSO CIRCUIT FOR CONTROLLING THE TEMPERATURE ,REPLY ME FRIENDS..

--------I HAVE BEEN STUCK FOR PAST 1 WEEK----------------

If any circuit is available for controlling the temperature..suggest me if so

3. MrChips Moderator

Oct 2, 2009
14,519
4,282
You cannot regulate a TEC with a potentiometer in parallel with the TEC.

A potentiometer in series will reduce the current but still will not regulate the temperature.

You need to google PID controller.

Apr 5, 2008
17,150
3,014
Hello,

I have moved the thread, as it is neither a feedback nor a suggestion.

Bertus

5. muthuaiyan Thread Starter New Member

Aug 4, 2014
19
0
hii chips,
PID controller is the only solution for controlling the cooling the temperature??

how about the LED intensity is varied by using the POT?

Apr 5, 2008
17,150
3,014
Hello,

A low power led will have a max current of about 20 mA.
A potentiometer might handle that amount of current.

A peltier element may take a current of several amperes, wich a potentiometer can not handle.
You can regulate the current in a peltier using PWM.
This PWM can be regulated with the information from the PID circuit.

Bertus

7. MrChips Moderator

Oct 2, 2009
14,519
4,282
You need a temperature sensor to measure the temperature.

A PID controller using analog or digital proportional control is the preferred method.

You can also use bang-bang control using a thermostat as a simpler controller.

8. muthuaiyan Thread Starter New Member

Aug 4, 2014
19
0
hai bretus.,

PWM signal generated through the PID controllers,but how can we vary the PWM input signal to vary the cooling temperature?

9. MrChips Moderator

Oct 2, 2009
14,519
4,282

Apr 5, 2008
17,150
3,014
Hello,

Have a look at the links of the following page of the EDUCYPEDIA:
PID Control Systems

Bertus

11. muthuaiyan Thread Starter New Member

Aug 4, 2014
19
0
hii chip,

by using only input supply i would like to control the temperature of the peltier not by using the temperature sensor LM35

12. alfacliff Well-Known Member

Dec 13, 2013
2,449
429
you can vary the temprature by varying the voltage to the module, but that will not regulate the temprature. we use peltier modules to cool machine cabinets, and they use a simple bimetal strip thermostat to control the temprature. on, off control. works better than compressed freon coolers, no ice, no big inductive surge when they cycle.

13. MrChips Moderator

Oct 2, 2009
14,519
4,282
Also remember that you have to remove the heat from the hot side of the TEC otherwise that is a sure way to blow a TEC.

14. muthuaiyan Thread Starter New Member

Aug 4, 2014
19
0
Hii alfcliff,

you are saying that i can vary the voltage to change the temperature.how if any circuits available

15. muthuaiyan Thread Starter New Member

Aug 4, 2014
19
0
still...
anybody can give me the clear answer..??

16. MrChips Moderator

Oct 2, 2009
14,519
4,282
Geez, you're not listening, are you?

Get one of these:

Aug 4, 2014
19
0
what is it??

18. wayneh Expert

Sep 9, 2010
13,635
4,430
You need a thermostat. You can very easily get good temperature control with a simple on/off thermostat, just like your home furnace. By "good" I mean ±0.5°C or less. But you must have something to sense the temperature.

It's possible that you might get a satisfactory result with a constant current or voltage supply, once you have carefully calibrated your system. You have not told us what your system is or the precision required.

As already noted, the biggest problem with a TEC is removing heat from the hot side. You need a heat exchanger and usually forced air convection. CPU coolers are commonly used.

19. crutschow Expert

Mar 14, 2008
16,563
4,475
Do you need a controlled temperature? For a controlled temperature you need a thermostat or other temperature sensor to control the TEC current (on/off or PWM).

Alternately if you only want to vary the cooling effect without close control of the temperature you can just vary the TEC current. A PWM source is the most efficient for that.

So which do you want?

muthuaiyan likes this.
20. MrChips Moderator

Oct 2, 2009
14,519
4,282
My soldering iron has an on-off (bang-bang) thermostat. It keeps the temperature of the iron at the desired temperature. I can feel and hear it click when the switch opens and closes.