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MIT Unveils Sun-Free Photovoltaics
An anonymous reader writes "Researchers at MIT just unveiled a new solar power generator that doesn't need sunlight to function. The button-sized power generator can tap energy from heat, the sun's rays, a hydrocarbon fuel, or a decaying radioisotope, and it can run three times longer than a lithium-ion battery of the same weight. It is hoped that the technology may one day be used to generate power for spacecraft on long-term missions where sunlight may not be available."
We use this thing to run a space heater, which in turn heats up the generator and provides even more energy. Bingo, we've got an endless energy supply. String a bunch of these puppies together and goodbye fossil fuels!
You're welcome, world.
SJW: Someone who has run out of real oppression, and has to fake it.
The button-sized power generator can tap energy from heat, the sun's rays, a hydrocarbon fuel, or a decaying radioisotope.
Looking at TFA, it looks like it takes heat, converts it to light in very specific frequencies, and then uses that to generate electricity. So, any source of heat whatsoever should theoretically be able to power these. We already possess thermoelectric generators, but they tend to be effective only at very specific and fairly low temperatures. Potentially, this kind of technology could replace conventional turbines in most power plants (nuclear, coal, et al. Basically, any that directly generate heat). Anyone know what kind of efficiencies these could operate at vs. steam turbines? I know turbines are fairly efficient (but large, hence this new tech), but it seems like these could (maybe) exceed those.
Also, if these things could be designed to require fairly low heat, then I imagine they could be used in basically any everyday device, generating low power from room-temperature heat. They don't seem to require the heat-differential of thermo-electric generators, so I wonder if they could supplement/ replace batteries in many daily electronic devices (pacemakers and hearing-aids come to mind, cell phones likely require way to much power). Anyone know if that kind of thing is at all practical?
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
So, Can I combine it with a battery and then use it as a heat sink for the CPU in my phone?
I only need juice until it gets hot, right?
/me sips his coffee and ponders a new sig...
Good point... The summary left off an important bit of information from TFA:
"Based on that technology, MIT researchers have made a button-sized power generator fueled by butane that can run three times longer than a lithium-ion battery of the same weight; the device can then be recharged instantly, just by snapping in a tiny cartridge of fresh fuel"
So... using this to convert butane to electrical energy it lasts three times longer than a lithium-ion battery of the same weight.
But if you look at energy density of the two fuel sources: http://en.wikipedia.org/wiki/Energy_density
You find that butane/propane/gas/diesel is about 45 megajoules / kg and Li-ion batteries store about 0.75 megajoule / kg. Converted energy 2.25 megajoules (3x Li-Ion) out of stored energy 45 megajoules = 5% efficiency rate converting butane heat to electrical energy using this device.
--David
did you punch the monkey? I think you need to punch the monkey to see the specs.
It breaks my pluginses, my precious!
And you've neglected to account for the actual mass of the butane/Li-Ion reactants vs the mass of the reaction chamber and TPV. The Li-ion battery needs only a casing, all the other mass is the anode and cathode. The TPV needs a container for the butane, a reaction chamber, ducting for air to enter the reaction chamber, and the separate TPV cell.
Then, we need to look at volumetric energy density comparisons too, as devising a container strong enough to hold a mass of butane with comparable energy in a similar volume to a Li-ion cell might be too heavy for a portable device. Both volumetric and gravimetric energy density are important in portable devices.
When we see actual efficiency ratings for these TPV devices, then we can evaluate their usefulness.
make imaginary.friends COUNT=100 VISIBLE=false
How old are thermocouples? Seriously folks, that someone took heat energy and created a current flow is no reason to go ga ga. Look at efficiency. Carnot heat engine is quite abstract and no matter what, there is an absolute maximum efficiency given the temperature of the source and the sink. Unless you have a bottomless pit of of sink at absolute zero degree kelvin, this sucker too would look very much like a thermocouple. Curious, interesting, might find some application in some weird situations. But in general, if ain't gonna replace either the IC engine or the battery any time soon.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
How low are the power demands of a pacemaker in terms of the Library of Congress?
i'd hit it so hard, if you pulled me out you'd be the king of britain [bash.org]