It's been 13 years I've never seen one

At just 14 years old, Ann Makosinski harnessed the warmth of her own hand to create a flashlight that needs no batteries. 💡

Her inspiration came from a friend in the Philippines who told her she couldn't study at night and was failing in school because her family had no electricity for light.

Ann wanted to find a way to help. She knew she could capture energy from many sources, including the heat from a human body.

She looked into Peltier tiles, which produce an electric charge when one side of the tile is heated and the other is cooled.

Ann realized that the heat from a person's hand on one side, and the ambient air cooling the other, could generate enough power for an LED light.

Using this principle, she designed the Hollow Flashlight. The design allows air to flow through the device, keeping the outside cool while the inside is warmed by the user's hand.

In 2013, at age 15, her invention won her top prize for her age group at the Google Science Fair.

Her simple, yet brilliant, device showed a new path for sustainable, off-grid energy solutions. 👋 #InnovativeYouth #SustainableEnergy #InventionSpotlight #fblifestyle

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Gibbon · 70-79, M

Hmm? I wonder where this went. It's not unbelievable. Thermal differences are currently used for energy generation. Iceland and Greenland both make use of this.

ninalanyon · 61-69, T

@Gibbon On the contrary, it is quite unbelievable! It didn't go anywhere because it is ludicrously ineffective and expensive.

The thermal differences in the Icelandic power systems are huge in comparison and the available power is also huge. The geothermal source are mostly used directly to heat houses, pavements, swimming pools etc. not to generate electricity in ridiculously inefficient Seebeck effect devices.

ArishMell · 70-79, M

@Gibbon What is used in Iceland and Greenland is totally different in both form and scale from this dubious hand-powered torch claim.

They use vast quantities of water at high source temperatures, therefore vast quantities of heat energy, to drive steam-turbines connected to alternators, or in large-scale central-heating systems.

The Peltier effect is reversible but very inefficient. One everyday example is the picnic-foods cool-box with a Peltier-junction array, heatsink and fan in its lid; driven from the car battery via the dashboard's 12V socket. It works to a point, and I use one; but its low efficiency means it requires a large quantity of electricity to transfer only a small quantity of heat across a modest temperature difference. It is hardly a refrigerator and would flatten the battery in a few hours if left running in a car with the engine turned off.

There is nothing new in curious claims of "inventions" supposedly revolutionising engineering, from "perpetual motion machines" to internal-combustion engines fuelled by water*; but no-one can defeat Physics. Indeed, such claims show simple scientific and engineering ignorance, including of the difference between heat and temperature, and the basic nature of energy.

.....

*The usual excuse for the disappearance of some of these outlandish "inventions" was suppression by the oil-companies. No: they disappeared simply by failure!