A Flashlight Of Fire And Ice

[Daniel Salião Ferreira] may or may not be a Game of Thrones fan, but he does have a fun demo of the Seebeck effect in the form of a flashlight powered by fire and ice. The basic idea is to use a thermocouple, but — in this case — he uses a Peltier effect cooler.

The Peltier and Seebeck effects are two sides of the same coin: the Peltier effect creates heating and cooling when current flows through a thermoelectric material. In contrast, the Seebeck effect generates a voltage when there is a temperature gradient. While thermocouples do produce voltage this way, they usually have much lower power output and are useless as heat pumps.

Thermoelectric heat pumps — Peltier devices — use semiconductors, which allow them to reach higher temperature differences when used as a heat pump, and also perform better than a conventional metal thermocouple in reverse operation.

Generating power from waste heat is nothing new. Is it harder to do this with thermocouples? Yes. Yes, it is.

15 thoughts on “A Flashlight Of Fire And Ice

      1. ‘couples are made with wires. Petier devices are sort of thermocouples made with semiconductors. So yeah, they work OK-ish for the car fridges. But a iron thermocouple, not so much ;-)

  1. The waves of energy are complex in the sheet, it don’t matter how you drive it. The suspensions should be longer. I really enjoyed the Moody’s reference, Darth’s voice wouldn’t do. MEMS mics would be most up to date. Those solid state pickups have two sides neither are ground, a little epoxy would insulate it balanced out. Ground the sheet! I’d use tiny electret mics in the contact mode myself though, yeah two. Mono is so regressive, my surround sound didn’t register any space at all. There are mass drivers “my china cabinet makes beautiful sound”, TV ad for such decades ago. Search invisible speakers.

  2. If you search for a “Luminizer” lantern, these are Seebeck LED lanterns powered by a candle/oil-lamp flame and are available for ~US$20 or so. Good for classroom demonstrations (and late-night picnics).

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