Super Soaker Inventor Hopes to Double Solar Efficiency 288
mattnyc99 writes "With top geeks saying photovoltaic cells are still four years away from costing as much as the grid, and the first U.S. thermal power plant just getting into production, there's plenty of solar hype without any practical solution that's efficient enough. Until Lonnie Johnson came along. The man who invented the Super Soaker water gun turns out to be a nuclear engineer who's developed a solid-state heat engine that converts the sun's heat to electricity at 60-percent efficiency—double the rate of the next most successful solar process. And his innovation, called the Johnson Thermoelectric Energy Conversion (JTEC) system, is getting funding from the National Science Foundation, so this is no toy. From the article: 'If it proves feasible, drastically reducing the cost of solar power would only be a start. JTEC could potentially harvest waste heat from internal combustion engines and combustion turbines, perhaps even the human body. And no moving parts means no friction and fewer mechanical failures.'"
probably meant in a more narrow technical sense (Score:5, Informative)
(I haven't RTFA to figure out for sure, but if they're talking "hydrogen" on one side of a reaction and "proton/electron" on the other, it seems plausible on first blush.)
Another misleading summary (Score:4, Informative)
I didn't see any details on how this is any better than century-old heat engine ideas, unless the solid state design allows dirt cheap mass production, in which case he might be onto something...
Re:Hmmm.... (Score:4, Informative)
He's not saying he found a more efficient solar cell (a doubling of that would be high on the BS scale). He is stating that he has created a new evolution of the Stirling Engine http://en.wikipedia.org/wiki/Stirling_engine [wikipedia.org].
From what I've read he looks to be on the up and up but again IANAP. Obviously since he has yet to have a production model we need to take it with a grain of salt but it looks very promising. *Crosses fingers*
Re:Not sure about this... (Score:3, Informative)
The engine does not require oxygen or a continuous fuel supply, only heat.
This might just mean that oxygen is not consumed, while it could also mean the system contains no oxygen.
But also...
On the high-pressure side of the MEA, hydrogen gas is oxidized resulting in the creation of protons and electrons... On the low-pressure side, the protons are reduced with the electrons to reform hydrogen gas.
Here it looks like the article describes the reaction: H => e- P+ => H
So I think you might be right: oxidize is equivalent to ionize
Re:Second Law of Thermodynamics (Score:5, Informative)
As I understand it, there's only a violation if that someone claims they can use ALL of the heat to do work (thermal efficiency of 1). If some heat is still being dispersed into a cooler temperature environment, it's still perfectly doable. After all, are you going to tell me you can't use waste heat from the ICE to heat up some water?
I'm not an expert in the subject (I'm an electrical engineer, so I've only gotten very basic freshman-level introductions to the laws of thermodynamics), but I think there's a well-known upper bound to how efficient recovery of heat to do work can be. Some googling led to wikipedia which tells me that upper bound is the efficiency of the Carnot Cycle [wikipedia.org]. Apparently it's not quite possible to reach it, but you're not violating thermodynamics if you're below it.
Re:Ohh yeah, he's qualified... (Score:3, Informative)
IOW, you still need a constant heat source. TFA mentions that they're working on a 200 degree C version, and managed to get their prototype going w/ 60% efficiency if the temp is at 600 degrees C... TFA also mentions that current solar furnaces can jack out around 800 degree C heat when you have a shitload of parabolic mirrors pointing at your boiler.
Overall, you're still taking in heat (read: energy) from an external source, so there's (from the looks of it) no cheating going on here.
First? (Score:3, Informative)
Way to mis-quote. According to TFA, that's the first solar thermal MANUFACTURING plant... As in, they make the equipment. There are several U.S. solar thermal power plants, dating back to the 70s.
Re:Ohh yeah, he's qualified... (Score:3, Informative)
Re:Anyone spot the danger? (Score:2, Informative)
Food production is an energy-intensive process. Even if it is some slop that is pumped into your bloodstream, there must be potential energy in the chemical bonds within the food, which of course, requires energy. The human body also doesn't metabolize all the food it consumes as energy and the metabolic process itself requires caloric input. Even if you collected 95% of the heat produced, you'd have an inefficient system that would not be close to producing enough energy to heat 1 kilogram of water 600C within a day. It would be more efficient to burn the food and collect the energy from that. Even better, skip the entire nutrition thing and just directly use the energy that would have been wasted in the yeast vats that maintain the useless humans.
Fortunately, the Matrix is more of an allegory on the philosophy of Idealism than a forum for discussing alternative energy.
Re:Not sure about this... (Score:3, Informative)
Re:And... (Score:4, Informative)
There is a limit to how much water is naturally evaporated from the ocean each year (far, far less than we're dumping into it) and rained down onto solid ground. There is a limit to how quickly water absorbed by the soil will leech down into the aquifers it was drawn from (it takes centuries) and that's where most of our water supplies comes from.
And as for location, there's no place on earth where the rainfall would possibly exceed the needs of a densely packed urban population, without conservation. The troubles Atlanta is having are just a start. Being located in the desert merely brings the problem to the forefront more quickly.
Look at the farm-packed interior of the US, and you'll find ridiculous quantities of water being used, all drawn from a gigantic aquifer, which is now being dramatically drawn down, with no sign of replenishment. You're welcome to go tell them they're just imagining it, when they run out of water supplies.
I'd gamble that, over the next decade, cities all across the US will have to begin copying the water conservation measures that have long been in-use in the southwest. And if they don't, the cost of water is going to go through the roof, as the expense for finding new supplies, and building new recycling facilities, goes through the roof.
Re:Oxidization (Score:1, Informative)
They overlap incompletely.
You can obtain ions by oxidation. You can also obtain ions by reduction.
However, many reactions involve pairs of oxidations and reductions, leading to no change in charge, and thus no ions.
HTH.
Also, mod parent up, just because they both start with "Ox" doesn't mean they have much to do with each other beyond the fact that Oxygen is a decent oxidizer.
not exactly :) (Score:5, Informative)
Re:sterling engine? (Score:5, Informative)
According to TFA, their first prototype is limited to 200*c because of material concerns. If they were to draw ice-cold water from the deep ocean as the cold side, it could theoretically acheive 473 / (473 + 273) or 63% efficiency. They talk about future materials allowing a hot side of 600*c, which despite being nearly twice the absolute temperature would only raise theoretical efficiency to 76%. Some sort of exotic oxide ceramic that could run at 1500 or 2000K would only add another 10% or so.
What fraction of that efficiency this or other engines acheive depends on the design. I believe the most efficient toy stirling engines can reach 90-96% of Carnot efficiency.
Re:Not sure about this... (Score:2, Informative)
Re:Second Law of Thermodynamics (Score:4, Informative)
This is why turbochargers are often used on high performance engines - it extracts extra energy from the exhaust flow and thereby raises the thermodynamic efficiency of the whole package. Typical exhaust gas temperatures (at the exhaust manifold) are on the order of 1500 degrees F, which is hot enough to do lots of work.
Re:Not sure about this... (Score:3, Informative)
Re:sterling engine? (Score:3, Informative)
Your math is slightly off. Carnot's theorem [wikipedia.org] gives the max efficiency as (Th - Tc) / (Th), or (200 / 473) = 42%. That is, the fraction of the energy you can remove is exactly equal to the fraction of the temperature you can remove. Plugging in 873 for Th (aka 600C) and 300K Tc (a very good radiator), I get 65%, which is on par with TFA's 60% number.
The interesting question is how close to theoretical they can get...
Patent 7,160,639 (Score:5, Informative)
Leapfrogging! (Score:5, Informative)
An example are cell phones. They've brought connectivity to folks in even isolated villages who could not dream of getting a land line.
Or the "life straw," a simple, cheap, but high-tech gadget that filters the filth and germs from streams. It's literally a straw.
Or a simple solar-charged LED light. Hang it outside your hut in the day, bring it in at night so the kids can study or mom can make extra money doing piecework.
A sturdy, self-contained solar electrical generator could act as an adjunct for a decentralized high-tech low-budget infrastructure. You'd use it to charge cell phones, XO Laptops (and their adult equivalent), and so on.
Re:And... (Score:3, Informative)
Kalina cycle (Score:3, Informative)
They are, with what's called a "bottoming cycle" that uses the steam that exits the low pressure turbine to heat a mixture of ammonia and water that boils below the boiling point of water alone, thus raising the working pressure enough to turn an additional turbine. This bottoming cycle is also known as the Kalina cycle, and is in use at combined cycle gas turbine plants (where the hot exhaust from a gas turbine is used to make steam to run another turbine).
Re:You cycle it (Score:3, Informative)
Another problem with hydrogen gas is that it tends to corrode and embrittle metals and other materials that are used to contain it (i.e. metal tanks, piping, etc) to the point where containment may eventually be compromised, particularly if high pressures and heat are involved.