Thermoelectric control

Projects Discussion and Showcase Product Design
1

Here’s my idea....while I realize that peltier modules are hot on one side and cold on the other, I want to be able to do it without contacting the module. I know a dpdt relay can flip the polarity of the unit and thus flip from hot to cold... my question is how to regulate temp once the flip is made. A single temp control (usually cold is how they come) but even if I have one for hot, then it’s two temp controllers battling each other. Any ideas????

2

bstebens:
Here’s my idea....while I realize that peltier modules are hot on one side and cold on the other, I want to be able to do it without contacting the module. I know a dpdt relay can flip the polarity of the unit and thus flip from hot to cold... my question is how to regulate temp once the flip is made. A single temp control (usually cold is how they come) but even if I have one for hot, then it’s two temp controllers battling each other. Any ideas????

My personal experience coincides with the product recommendations and that is to wait at least 15 minutes with power off when switching from cold to hot and the other way around, as well. There is MORE heat generated in the internal diodes that is transferred from one side to the other and you must wait for that heat to stabilize.

Please think about regulating temperature without knowing what the temperature is? How does that work?

My project used two DPDT relays to switch from hot to cold. With only one relay switched, the circuit is open for temperature stabilizing. After 15 minutes, switch the second relay. And I did not care about stabilizing either cold or hot.

Paul

Paul

3

Consider a H bridge, you only need one and it is does not make noise. You can control with a PWM signal and control direction with a Dual BTS7960 B BTS7960B DC 43A H-Bridge PWM Stepper Motor Driver Module Board For Arduino MCU Smart Car Robot available from many sources for just a few dollars. The Arduino will do a good job for you and you get the fun of designing and building it. All of your concerns can be resolved with the Arduino Software.
Good Luck & Have Fun!
Gil