New way of producing electricity...

[Rajiv]

FWIW, -- 100% Efficient Wood Stove (or gas furnace) ! ! !

Now I am not here to argue what the word efficiency means, I am simply talking about capturing 100% of whatever heat is generated through combustion such that the exhaust is cooled down below average room temperature before departing.

Here is how simple it can be.

Use a blower fan to produce a forced draft and draw your exhaust through a series of heat exchangers (could be as simple as 55 gallon steel drums filled with brick pieces or large gravel). Each “container” would be filled with smaller sized pieces and the last one or two would be filled with sand. It is even possible to use wet sand to more quickly and effectively capture the last remaining heat as long as you provide the means of moistening the sand before each burn. BTW . . . the air is cooled before it ever reaches the fan.

Of course there are many things to be considered such as:

• Burn has to be as complete as possible (technique)
• Fuel needs to be as dry(or clean) as possible
• Looping heavier smoke back to burn chamber during early moments of burn would help eliminate most of what little deposits would be generated.
• Generally speaking, the cost to run a fan is far less than the cost to generate heat.
• Since you are capturing all of your heat, a wide open clean burn will not waste heat.
• Draft can be totally controlled by fan speed rather than by opening vents.
• Design must allow for air inlet to close should power to fan go out. ( one or more ultra light weight “doors” that swing open during draft and fall closed when suction stops).

Now this may not work on every combustion heater in the world (gas, oil, wood, pellet, coal . . .) but it would work on a lot of them. If we saved the 10% to 50% of heat that is going up all of those chimneys, the impact would be tremendous. Also, the potential is here to eliminate buying/building an expensive chimney while making the combustible heater safer to operate at a fraction of the cost.

It takes masonry heaters to a whole new level . . .the final level. Cooled down exhaust can be vented almost anywhere outside or even underground. What about heating a greenhouse with a wood stove and then venting almost pure CO2 and H2O vapor back into the house???? What do you think?

[dcarrigg]

New way of producing electricity...

http://www.physorg.com/news187186888.html

What about this doesn't sit right with me? Second law of thermodynamics? Ash, do you have any input on the matter?

[Starving Steve]

Re: New way of producing electricity...

Next to nothing is almost zero is almost zero is: a big bunch of NOTHING. Got it?

ZERO. Zip. Nada. Cero. Basura. Junk.

It took the world thousands of years to discover that zero had meaning as a number, and sadly, some in this world still don't get it. 0 = 0.

You can smoke all of the pot that you want, but nothing is nothing.

Solar energy is as close to being nothing as I can think of on Earth. NOTHING. So carbon waves in nano-tubes produce only the amount of electrical energy that they have from input heat. Got it? And they might even produce less energy than they have from input heat. Things go down-hill, not up-hill. No free lunch. Got it?

No free lunch, not even in physics, nor mechanical engineering. Not at MIT, nor Berkeley, nor anywhere. Zero is zero.

And the economics profession is the same kind of thinking: a free lunch from paper money. Sorry, but it doesn't exist, and never did.

The lesson is to put your talents and energy into things that you know work well, and do more of what works well, and less of what doesn't work. So bury the solar energy crap, and get real.:rolleyes:

If we ever dig-out of the Great Recession, it will be by producing vast amounts of energy from coal, oil, natural gas, tar sands, hydro-electricity, and atomic power. Got it? We will do what works and do a lot of what works.

Now get sober.

[bw]

Re: New way of producing electricity...

Nothing in the article says it puts out more power than goes in, it just says it's a new way to generate electricity. Like a thermocouple or piezo-electric, just another mechanism. Nothing magical.

[thriftyandboringinohio]

Re: New way of producing electricity...

Next to nothing is almost zero is almost zero is: a big bunch of NOTHING. Got it?

ZERO. Zip. Nada. Cero. Basura. Junk.

It took the world thousands of years to discover that zero had meaning as a number, and sadly, some in this world still don't get it. 0 = 0.

You can smoke all of the pot that you want, but nothing is nothing.

Solar energy is as close to being nothing as I can think of on Earth. NOTHING. So carbon waves in nano-tubes produce only the amount of electrical energy that they have from input heat. Got it? And they might even produce less energy than they have from input heat. Things go down-hill, not up-hill. No free lunch. Got it?

No free lunch, not even in physics, nor mechanical engineering. Not at MIT, nor Berkeley, nor anywhere. Zero is zero.

And the economics profession is the same kind of thinking: a free lunch from paper money. Sorry, but it doesn't exist, and never did.

The lesson is to put your talents and energy into things that you know work well, and do more of what works well, and less of what doesn't work. So bury the solar energy crap, and get real.:rolleyes:

If we ever dig-out of the Great Recession, it will be by producing vast amounts of energy from coal, oil, natural gas, tar sands, hydro-electricity, and atomic power. Got it? We will do what works and do a lot of what works.

Now get sober.

Nice screed, Steve. It's always a delight to watch a master work his craft.

This research seems far too preliminary to deserve your scorn just yet. Maybe after someone builds a device and tries to sell it to someone else we can say "you saw it bashed here first". You are several years too soon to blame it on pot smoking.

The whole thing right now is a one-shot device more like a firecracker. The carbon nano-tube are coated with a "reactive fuel" ( i.e., explosive) that creates electricty as the little line charge races down the nantube. All very much still strung together on a lab bench with no practical application in sight.

I'd love to hear Ash's take on the basic phenomenon of a passing wave of heat carrying electrons along with it down a carbon fiber.

In the new experiments, each of these electrically and thermally conductive nanotubes was coated with a layer of a reactive fuel that can produce heat by decomposing. This fuel was then ignited at one end of the nanotube using either a laser beam or a high-voltage spark, and the result was a fast-moving thermal wave traveling along the length of the carbon nanotube like a flame speeding along the length of a lit fuse. Heat from the fuel goes into the nanotube, where it travels thousands of times faster than in the fuel itself. As the heat feeds back to the fuel coating, a thermal wave is created that is guided along the nanotube. With a temperature of 3,000 kelvins, this ring of heat speeds along the tube 10,000 times faster than the normal spread of this chemical reaction. The heating produced by that combustion, it turns out, also pushes electrons along the tube, creating a substantial electrical current.

Combustion waves — like this pulse of heat hurtling along a wire — “have been studied mathematically for more than 100 years,” Strano says, but he was the first to predict that such waves could be guided by a nanotube or nanowire and that this wave of heat could push an electrical current along that wire.

In the group’s initial experiments, Strano says, when they wired up the carbon nanotubes with their fuel coating in order to study the reaction, “lo and behold, we were really surprised by the size of the resulting voltage peak” that propagated along the wire.

After further development, the system now puts out energy, in proportion to its weight, about 100 times greater than an equivalent weight of lithium-ion battery.

The amount of power released, he says, is much greater than that predicted by thermoelectric calculations. While many semiconductor materials can produce an electric potential when heated, through something called the Seebeck effect, that effect is very weak in carbon. “There’s something else happening here,” he says. “We call it electron entrainment, since part of the current appears to scale with wave velocity.”

The thermal wave, he explains, appears to be entraining the electrical charge carriers (either electrons or electron holes) just as an ocean wave can pick up and carry a collection of debris along the surface. This important property is responsible for the high power produced by the system, Strano says.

one possible application would be in enabling new kinds of ultra-small electronic devices — for example, devices the size of grains of rice, perhaps with sensors or treatment devices that could be injected into the body. Or it could lead to “environmental sensors that could be scattered like dust in the air,” he says.

In theory, he says, such devices could maintain their power indefinitely until used, unlike batteries whose charges leak away gradually as they sit unused. And while the individual nanowires are tiny, Strano suggests that they could be made in large arrays to supply significant amounts of power for larger devices.

The researchers also plan to pursue another aspect of their theory: that by using different kinds of reactive materials for the coating, the wave front could oscillate, thus producing an alternating current. That would open up a variety of possibilities, Strano says, because alternating current is the basis for radio waves such as cell phone transmissions, but present energy-storage systems all produce direct current. “Our theory predicted these oscillations before we began to observe them in our data,” he says.
Also, the present versions of the system have low efficiency, because a great deal of power is being given off as heat and light. The team plans to work on improving that

http://nextbigfuture.com/2010/03/mit...ves-which.html

[dcarrigg]

Re: New way of producing electricity...

Nothing in the article says it puts out more power than goes in, it just says it's a new way to generate electricity. Like a thermocouple or piezo-electric, just another mechanism. Nothing magical.

I understand that it's nothing magical, but there are no piezoelectric batteries for a reason, and the article (maybe just the article's fault) compares the technology to Li-ion batteries - I don't see how this mechanism could be utilized as a battery - that's all.

[ASH]

Re: New way of producing electricity...

http://www.physorg.com/news187186888.html

What about this doesn't sit right with me? Second law of thermodynamics? Ash, do you have any input on the matter?

Nothing in the article says it puts out more power than goes in, it just says it's a new way to generate electricity. Like a thermocouple or piezo-electric, just another mechanism. Nothing magical.

The whole thing right now is a one-shot device more like a firecracker. The carbon nano-tube are coated with a "reactive fuel" ( i.e., explosive) that creates electricty as the little line charge races down the nantube. All very much still strung together on a lab bench with no practical application in sight.

I'd love to hear Ash's take on the basic phenomenon of a passing wave of heat carrying electrons along with it down a carbon fiber.

I agree with BW and Thrifty. What the researchers describe sounds physically plausible to me, but it doesn't sound like this effect will find any broad application as an alternative energy source. This isn't a new primary source of energy so much as a new process for converting stored chemical energy directly into electrical current, embodied in a very compact physical form. To my mind, this might become a sort of compact "super-battery" for applications that require a very brief burst of high current, but is unlikely to be relevant to applications requiring (a) the ability to recharge the battery, or (b) sustain power output. We're not talking about transportation or power grid here.

As Thrifty notes, the article describes a one-shot chemically-fueled generator. The article itself remarks that "the present versions of the system have low efficiency, because a great deal of power is being given off as heat and light." Any application would be capitalizing on the high energy storage density of the material, the ability to convert chemical energy into electrical current without any moving parts, and the long-term stability of the energy storage. I can see this eventually being useful for all sorts of military applications (stored power source for a chemically-driven EMP bomb, one-use burst transmitter for a chem/bio or intrusion microsensor, etc.).

I notice the article mentions this isn't due to the Seebeck effect, which is why the researchers are describing the phenomenon as 'new'. I assume that the thermal wave that is referred to in the article as traveling 10,000 times faster than the chemical combustion front is vibrational motion (essentially a mechanical shock wave, I'd guess), and I know that you get momentum coupling between lattice vibrations and electrons all the time in solids, so the 'entrainment' mechanism they invoke to explain the current seems reasonable.

[ASH]

Re: New way of producing electricity...

I understand that it's nothing magical, but there are no piezoelectric batteries for a reason, and the article (maybe just the article's fault) compares the technology to Li-ion batteries - I don't see how this mechanism could be utilized as a battery - that's all.

I agree that it couldn't be used in most of the same applications as a Li-ion battery. The comparison probably makes sense if you start by assuming that you've got a specialized application where you want a jolt of current, rather than a sustained draw. So, option #1 is to use a Li-ion battery plus maybe a big capacitor to build up a good jolt, and now option #2 is to use a physically smaller amount of this material instead of the Li-ion battery, and omit the capacitor, too. But this isn't going to power an RC car or a cell phone.

[cmalbatros]

Re: New way of producing electricity...

Second law of thermodynamics? I am no expert but this law does not seem to be broken when all one is doing is to capture the energy coming to us from the sun. Scientists at San Diego University have designs for nano silicon wafer generators, a cubic meter of them will produce the same power as a nuclear power plant.

[thriftyandboringinohio]

Re: New way of producing electricity...

I agree that it couldn't be used in most of the same applications as a Li-ion battery. The comparison probably makes sense if you start by assuming that you've got a specialized application where you want a jolt of current, rather than a sustained draw. So, option #1 is to use a Li-ion battery plus maybe a big capacitor to build up a good jolt, and now option #2 is to use a physically smaller amount of this material instead of the Li-ion battery, and omit the capacitor, too. But this isn't going to power an RC car or a cell phone.

There is a kind of battery commonly used in guided missles called a "thermal battery". Advantages are huge power output and very long shelf life. The electrolyte is solid at room temp. At time of use, a pyrotechnic pellet is lighted inside the battery that burns very hot and melts the electrolyte. Typically a half minute or so of very strong output, but of course is a one-shot device. The electrolyte in thermal batteries includes lithium in the chemistry. Such disposable-but-hazardous thermal batteries are much more powerful than rechargeable lithium-ion batteries like the one in your phone. A beautiful way to power the seeker head on a hellfire or sidewinder.

[Glenn Black]

Re: New way of producing electricity...

http://www.physorg.com/news187186888.html

What about this doesn't sit right with me? Second law of thermodynamics? Ash, do you have any input on the matter?

Graphene sheets are now being used in computer chip manufacturing, 1 atom thick lattice of carbon, very high speed, low cost compared to rare earth doping.

Having a heat wave faster than the fuel's flame front??? That means a runaway reaction, or flame-out as all the heat is dissapated before the next amount of fuel is ignited. This would require a new ignition source with each flame front. A highly dynamic situation.

But, then again real life at quantum level can do strange things.

[Starving Steve]

Re: New way of producing electricity...

Second law of thermodynamics? I am no expert but this law does not seem to be broken when all one is doing is to capture the energy coming to us from the sun. Scientists at San Diego University have designs for nano silicon wafer generators, a cubic meter of them will produce the same power as a nuclear power plant.

Get off of the pot and sober-up. :rolleyes:

[Starving Steve]

Re: New way of producing electricity...

I agree that it couldn't be used in most of the same applications as a Li-ion battery. The comparison probably makes sense if you start by assuming that you've got a specialized application where you want a jolt of current, rather than a sustained draw. So, option #1 is to use a Li-ion battery plus maybe a big capacitor to build up a good jolt, and now option #2 is to use a physically smaller amount of this material instead of the Li-ion battery, and omit the capacitor, too. But this isn't going to power an RC car or a cell phone.

Spending the afternoon swinging a giant mallet over my head and splitting stumps--- whilst cursing every pot-heat eco-nut that lives by me in East Sooke, British Columbia--- the way I figure things is like this: The day that MIT or Berkeley develops a method to electrically power a house using the waste heat that goes up the smoke stack from a wood stove, then I would be all ears. Until that day, I am not interested in new pot-head discoveries about lithium-ion batteries, nor about energy waves being burst-forth from carbon fibers, nor about cubic meters of new super-conducting solar cells.... All of it is B.S.:rolleyes:

[sunskyfan]

Re: New way of producing electricity...

I would hesitate to guess at the lack of importance of the article. The new phenomena being observed as folks figure out how to form specific structures at atom dimensions continues to surprise. Whether someone finally actualizes room temperature superconductors or some "palladium" like matrix that enables the holy grail (if taboo idea) of cold fusion is possible (not probable) will probably come from this type of research. Remember, the basic physics of the Laser was started by Einstein in 1917 but a functional laser didn't really happen in the 1960s.

[ASH]

Re: New way of producing electricity...

Having a heat wave faster than the fuel's flame front?

The article describes this as a chemical fuel burning rather than an explosive detonating, so it is a good bet that the flame front is sub-sonic (lets say less than 0.343 km/s). On the other hand, the average phonon velocity in a nanotube at room temperature is estimated to be about 8 km/s (see Fig. 1 of the link). At one level, this just amounts to the observation that sound travels faster in most solids than it does through the air. The heat in the nanotube is carried by lattice vibrations which can outpace the progress of the flame front.