Generating energy from heat: the stove light, the hybrid charger?

degarb

Flashlight Enthusiast
Joined
Oct 27, 2007
Messages
2,036
Location
Akron, Ohio
Looking at your stove light which ledsupply posted on their facebook page, : heat is used to generate electric http://www.stovelite.com/.

Could this energy generation be applied to the automobile industry? Help charge the hybrid battery using wasted engine/muffler heat? Etc.? Could be revolutionary, or at least add a few mpg.


Probably comes down to how many watts of heat to watts of electric, cost, etc. Really would need real numbers.

I can't think of another application, unless you live in Iceland or Yellowstone. Or deep drilling for a constant supply of geothermal. Again, numbers needed.
 

StorminMatt

Flashlight Enthusiast
Joined
Oct 30, 2012
Messages
2,263
Location
Norcal
This light uses a thermoelectric module to generate electricity from the stove. Other products use the heat of a woodstove to power fans to distribute heat or even generate power for other uses. As for vehicular use, they have been proposed in conventional cars as a replacement for engine driven alternators. Thermoelectric devices would be placed on the catalytic converter in order to utilize waste heat produced there. This would, of course, eliminate the losses involved with driving an alternator. Thermoelectric devices can also be used to recover waste heat from many other sources, including industrial processes.


Of course, the nemesis of thermoelectric devices has always been low efficiency. This is probably the reason why this technology became abandoned shortly after its early-mid 19th century inception in favor of rotating generators. The main problem with thermoelectric devices is that they conduct most of the heat delivered to them straight through the device and out the heatsink. Development of better themoelectric materials could improve efficiency. But the HUGE problem is that efficient thermoelectric devices need a material with high electrical conductivity and low thermal conductivity (which are kind of mutually exclusive). A new lead-tellurium material has recently been developed that could possibly raise efficiency from the current 5-8% to around 20%. This could GREATLY increase the usefulness of thermoelectric devices. Graphene-based thermoelectric materials promise even higher efficiencies. But whether they will materialize is still uncertain.
 

RetroTechie

Flashlight Enthusiast
Joined
Oct 11, 2013
Messages
1,007
Location
Hengelo, NL
But the HUGE problem is that efficient thermoelectric devices need a material with high electrical conductivity and low thermal conductivity (which are kind of mutually exclusive).
There's no fundamental reason for that, but yes in practice thermal and electric conductivity seem related. :confused: Efficiency of these devices is usually low. Sometimes that matters, sometimes it doesn't.

Me I like the BioLite CampStove. Or on a more serious note, their HomeStove. Let's hope prices go down as numbers go up...
 

StorminMatt

Flashlight Enthusiast
Joined
Oct 30, 2012
Messages
2,263
Location
Norcal
There's no fundamental reason for that, but yes in practice thermal and electric conductivity seem related. :confused: Efficiency of these devices is usually low. Sometimes that matters, sometimes it doesn't.

Me I like the BioLite CampStove. Or on a more serious note, their HomeStove. Let's hope prices go down as numbers go up...

Generally speaking, thermal conduction of electrical conductors is predominantly electronic in nature, depending on high electron mobility. High electron mobility also leads to high electrical conductivity, thus the connection between thermal and electrical conductivity. A lot of research into better thermoelectric materials is focused on decreasing the acoustic (ie lattice vibration) thermal conductivity, since this can be decreased without reducing electrical conductivity.

As for the Biolite Stove, I have one myself. And it's pretty impressive. Being able to charge an iPhone with sticks is a pretty awesome thing! Not to mention that it's pretty good even when just used as a portable chimenea. It's not without its flaws, though. Power output is fairly low for one. Even my solar charger SERIOUSLY puts it to shame when it comes to charging speed. It can't really charge AND run the phone (unlike the solar charger). And forget trying to charge a tablet! Also, you actually need a fairly vigorous fire to keep it charging. Otherwise, it stops charging so that thermopile power can at least run the fan. What this stove REALLY needs is a larger, more powerful module (and they ARE available). But this would no doubt increase price. And regardless, this is a 'first of its kind' device which is sure to improve with later models.
 
Top