This week’s selection is the Personal Peltier Cooler by designer Jarno V.
This is a very unusual item that leverages a peculiar thermodynamic mechanism: the Peltier effect. According to Wikipedia, The Peltier effect is:
“The Peltier effect is the presence of heating or cooling at an electrified junction of two different conductors and is named after French physicist Jean Charles Athanase Peltier, who discovered it in 1834. When a current is made to flow through a junction between two conductors, A and B, heat may be generated or removed at the junction.”
In other words, when electricity flows through a specific set of materials, one side cools and the other is heated. Heat is transferred from one side to the other, much like a heat pump would do, except that this is entirely solid state — no moving parts. It’s called “Thermoelectric cooling”.
This project uses that phenomenon to produce a personal device to cool yourself on hot days, something quite welcome in this season of climate change.
Thermoelectric Cooling And 3D Printing
Physically, it’s designed to be a wrist-worn device that cools you by indirect access to your bloodstream. By placing the cool side of the thermoelectric cooling element on the inside of your wrist, it is relatively close to your veins. By cooling this blood flow, it rapidly carries through your entire body, cooling you down as a whole.
This wrist-based approach for cooling was apparently also used by soldiers in the Gulf, who would immerse a hand in a cooling solution. This would rapidly bring down their body temperatures, even on the hottest summer days.
The Personal Peltier Cooler will not be quite so effective, but it does work. In fact, Jarno V says:
“Attach it to your wrist for optimal blood flow. Best used in my opinion between 5v to 8v. You could use up to 12v but be careful it doesn’t get too cold (or too hot on the other side of the Peltier module).”
There is a fan on the device, but don’t be fooled: that is not what is causing the cooling effect. The cooling is entirely thermoelectric. The fan’s job is to remove excess heat that collects on the heatsink that’s attached to the hot side of the Peltier unit. Your heat will be blown away by this fan.
Building the Personal Peltier Cooler
Building this project is relatively straightforward; there is a wristband and housing for the cooling unit, as well as a lid that must be 3D printed. Aside from printed parts you will need the Peltier cooling unit, a heatsink and a fan. Oh, and you’ll also need a power source to energize the Peltier unit and the fan.
Most of these components are easily found, and you may even have some on hand, but the Peltier unit might be a bit rarer. However, it’s relatively easy to find them online, like this 40X40MM 12V 60W Heatsink Thermoelectric Cooler Cooling Peltier Plate Module available on Amazon for only ten bucks.
The files for producing the Personal Peltier Cooler are all available online for free download at Thingiverse courtesy of Jarno V.