Does that sound like a question where the answer is a definite no? Perhaps ‘maybe’ might be the better answer. Because you might actually enjoy wearing a thermoelectric generator, if you knew what it was or unless you already do.
The Principles of Thermoelectric Generation
The word ‘thermo’ refers to warmth or heat. A temperature difference could generate electrical energy if we knew how. That piece of ‘heavy lifting’ has already been done. Thermoelectric generation is alive and well!
We have a natural phenomenon, the Seebeck Effect, to thank for this. This phenomenon occurs when there is a temperature variation between two joined, different metals. This difference creates a small electric current, without a battery or moving parts required.
Practical examples include thermocouples in gas ovens and industrial furnaces, that measure temperature. As well as devices that convert heat from car exhausts (or space probes) into electricity. But would it be safe to wear a thermoelectric generator on your arm?
How Wearable Thermoelectric Generation Works
Wearable thermogenerators convert body heat into electricity, using the same Seebeck Effect. Temperature differences across materials drive an electron flow between them. This produces small electrical power for sensors, or low-energy wearables, safely.
However, this time the temperature difference does not come directly from different metals at different temperatures. It comes from the temperature difference between the environment and your body:
Your skin is naturally between 32 and 37°C (90 and 97°F). While the air, and our clothing are cooler. Here’s how a wearable ‘sandwich’ thermogenerator works:
- One side presses against your warmer skin. The other side is the cooler air (or a heat-dissipating layer).
- The two different conductive materials are inside that ‘sandwich’. When one side is warmer, the electrons can flow.
- One material gains more energy than the other. This imbalance drives a small electric voltage, through the Seebeck Effect.
So would you wear a thermoelectric generator now you know how it works? If you are using a wearable device without a battery, you most likely are!
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