Has anyone made a flashlight that uses the Seebeck effect to recycle the waste heat generated in a high powered flashlight and recycle it into electricity that can charge the battery.
This would serve two useful purposes:
From what I read Seebeck generators are not very efficient, but it’s still a net positive.
There is no way that I know of to have a flashlight behave like a Toyota Prius witht its regenerative braking.
With some light weight googling I found a story of a young woman who made a flashlight that used body heat converted to electricity to power a flashlight.
So there is a project out there that has some elements of what I’m suggesting.
It may be possible but if it weighed 25 lbs and cost $10,000. It would not be practical.
The body heat thing is only when there is a substantial temperature differential. Also, the current it generates is kind of low, probably enough to power a few 5mm LEDs. Good for an emergency light, or a side-of-a-house outdoor lighting where it can take the differential of outside and inside to convert it to power so the lights are essentially always on low.
You could probably coat a house in the stuff plus piezoelectric components to be always supplying low currents to a small battery array.
Heat is almost the worst kind of energy to recycle. Whatever you do, it would be so inefficient that it’s not even worth to try.
Heat is just another wavelength of light. I wonder if an infrared specific photoelectric/piezoelectric panel could maximize energy capture?
There seems to be some ambiguity in the discussion over what heat is: infrared radiation or the kinetic energy of particles.
As a sidenote, I find it strange that many sources identify infrared light with heat–it’s just light that we can’t see, yet nobody refers to UV as heat. Heat, defined as “high temperature”, is the result of energy conversion when infrared light hits an absorbent target–it is an effect of infrared light, but not infrared light itself.
Of course, hot objects also emit infrared (and other) radiation, which is consistent with their being separate entities.
I guess the same argument could be made for microwaves…any non-zero frequency of light/em waves will impart some form of energy to an absorbant material. That said, I don’t know of a single hot object that DOESN’t emit infrared…maybe vantablack?
That raises a very interesting point! The blackbody spectrum at any temperature, in theory, covers the entire EM spectrum. It’s just that we don’t detect the entire EM spectrum in practice because of (1) how fast the probability density drops off, and (2) how little power is emitted by low-temp objects.
In the range of temperatures we encounter on a daily basis, the peak of the emission happens to fall within infrared. This should not be particularly surprising, since the IR spectrum spans more than 3 orders of magnitude, while the visible spectrum spans only 1/4 of an order of magnitude.
At temperatures that are relevant at cosmic scales, the peak of the emission often falls within other bands of the EM spectrum. The “cosmic microwave background” at ~2.7K is called so because at this temperature, almost all emission is in microwave territory.
On the other hand, above 8000K or so–not at all uncommon for stars–most of the emission is much more energetic than visible light, with a peak firmly in UV territory. Yet we still see bright visible emission from them. If we could see room-temp EM radiation at this power, we would probably see visible light.
Here’s a great blackbody plotter to play around with: Spectral Calculator-Hi-resolution gas spectra
Wow this thread went off on a tangent. Gotta love BLF.
Looking at my original thought, many lights have extra material from the reflector down to the driver area. Oft times with fins for improved heat sinking.
Why not have this extra material instead include some thermoelectric generator material instead. Maybe clad it with aluminum for protection and aesthetics.
Then you can feed back the electricity made to the battery or to the driver.
Was confused by this as I’m familiar with Thermoelectric generators (TEGs) and the general inverse concept the Peltier cooler only to discover this is yet another name for the same concept.
I recall the yield was milliwatts - enough power to dimly light a few 5mm LEDs.
I fear the concept has some pitfalls. While a hot LED will generate higher-quality waste heat than the hand, it’s still apt to be quite low; factoring in additional electronics to feed back into the driver to reduce battery load may be a wash at best. Your collector also likely also won’t remove heat to the LEDs’ satisfaction, causing thermal issues.
I tried with a peltier plate, extremely inefficient.
Alright, this is way, way beyond my knowledge base, but for our resident computer/IT experts, what about unlocking the potential of the MSI Afterburner software in the further development of driver firmware?