Trying Out the Peltier Heating / Cooling

A project log for Tactile Tactical Interface

Heat/Cold/Vibration interface for situational awareness for firefighters, police, military, transportation, gaming, etc.

disasterarchydisasterarchy 08/22/2018 at 18:030 Comments

So now that I have all the parts, I have begun to experiment with them to see how they work by themselves.  First I am going to have a look at the Peltier module.  Peltier modules use the thermoelectric effect to produce a temperature gradient when given an applied voltage and can also produce a voltage when given a temperature gradient.  For more info on how they work and a description of what their naming convention is, you can read this.

My module is a TEC1-12705 which is 40mm x 40mm.  I first tried powering it with a Li-Ion cell, giving it about 4V.  Later I tried using a 5V power supply that I have.   All of the following results are with a 5V power source and drawing about 1 to 2 amps.  For more details see the datasheet

When holding the peltier, you can feel one side getting hot and the other side getting cold just few seconds after turning it on.  However to really make it work, you need to install a heatsink so that the hot side doesn't become really hot and let heat back into the cold side.  For my first heat sink I used a giant aluminum piece of scrap that we have sitting around the lab. 

I originally just placed the module on the aluminum, but this didn't work very well.  Then I applied a small amount of thermal paste and that didn't work much better.  I applied a generous portion to coat the whole hot side of the module and that worked really really well.  Here you can see that the hot side is 29 C and the cold side is -4.5 C.  The cold side is below freezing while the hot side is only slightly warm!  The aluminum block is doing a great job pulling away all the heat. 

I also realized that you can just reverse the voltage to cause the peltier to switch which side is hot and which is cold.  This is really great for my application and it means that I don't need to build in a separate heater (the conductive fabric) anymore.  I can use the same peltier modules to produce hot and cold.