Micro Fuel Cells

[don c.]

ALBANY, N.Y., Sept. 21 — Cell phones free from nightly recharges. Laptop computers that run and run without needing an outlet. Pocket TVs with enough power to show a Ken Burns documentary. Portable gadgets are demanding more and more juice. A viable alternative to rechargeable batteries isn’t here yet, but when it comes, it might work like the device about the size and weight of a deck of cards in William Acker’s hand. It’s a micro fuel cell.

Micro fuel cells are expected to get smaller. In the long run, just about anywhere where high-end batteries are the right answer, these devices should be a better answer (my emphasis), Acker said. Micro fuel cells are supposed to have several advantages over rechargeable batteries. Once fully developed, micro fuel cells should last 10 times as long as the current generation of batteries, Acker said. And no more recharges. When a fuel cell runs out of methanol, just snap on a replacement fuel cartridge. Also, fuel cells can provide more power. The potential for a lucrative market has drawn a mix of start-ups and big names. Nash cites Motorola, Toshiba and Casio, which has developed a fuel cell it intends to sell commercially in 2004.

Smart Fuel Cell, a German company, recently introduced a device fueled by a 2.5 liter methanol cartridge that can be used with outdoor equipment.

more at: http://www.msnbc.com/news/810641.asp

[Seeker]

I'm sure 'micro' fuel cells , will catch on in a 'big way' !

As with all developing technologies, they have some issues to work through, and it sounds like heat removal is one of them.

"The challenges facing micro fuel cells in order for commercialisation to take place - Heat removal, system power requirements, efficiency, miniaturization, methanol cross over."

http://www.eyeforfuelcells.com/events/boston2002/


If you don't mind lugging around a briefcase sized stirling, this might help with the heat removal :

" Kamen hopes that his family of Stirlings, five years in development, will soon bring portable electricity to nations without a reliable power grid - or any grid at all. He envisions briefcase-sized Stirlings powering cell phones and cell towers, as well as purifying water. He aims to have them on the market in the next two years, and is currently working on the marketing issues "

http://www.wired.com/wired/archive/8.09/kamen_pr.html

Seeker

[ftropea]

Ok, but the question is...

Would a micro-Stirling be more/less efficient in terms of power production -vs- fuel consumption than a micro-fuel cell?

Regards,

Frank A. Tropea

EDIT: Clarified my poorly worded question.

[Seeker]

quote:Originally posted by ftropea

Ok, but the question is...

Would a micro-Stirling be more/less efficient in terms of power consumption than a micro-fuel cell?

Regards,

Frank A. Tropea


Hi Frank,

Since excess heat production is one of the problems to overcome with micro fuel cells, I was thinking you could couple the fuel cell & stirling together. So you would use the excess heat from the fuel cell, to power the Stirling.

But then again this would add to the weight,and size of the power generation system, and also to the cost of it.

Seeker

[ftropea]

This is one thing I've always wondered about... The idea of just plugging Stirlings wherever you have excess heat. I once proposed a sort of nanotechnological approach to utilizing the Stirling engine. Imagine tiny Stirling engines.. the cylinder a ring of atoms.. the piston made of some magnetic material. The outside of the cylinder is wrapped in a coil of copper atoms... as the working gas/atoms is being displaced, the magnetic piston moves up and down... The magnetic field interacts with the copper coil, producing electricity.

Now imagine millions of these nano-stirlings mixed with another conductive subtance - in the form of a "paint" and that this paint is applied to a surface.. This surface is conductive on one side and insulated on the other. The non-conductive side is bonded to a heat producing source, say the exterior of your car engine.. the conductive surface is connected to "leads" which pull the electrons away into a battery/capacitor...

The conductive surface is layered in an protective laminate.. protection from water.. scratches.. etc...

Just an idea floating in my mind...

Regards,

Frank A. Tropea

EDIT: The cylinder itself could be the copper coil... capped at either end. That might be simpler...

[ftropea]

The idea of using the magnetic piston and copper coil is to simplify the electric production aspect of the Stirling.. no external generator needed.. or flywheel... don't know if it works theoretically, but I'm thinking nano-tech.. so maybe it could work. Trying to keep it simple..

Regards,

Frank A. Tropea

[Seeker]

################

[yop]

Efficiency:
The theoretical efficiency of a Stirling is 50%; the theoretical efficiency of a fuel cell is close to 100%. So once they manage to build a "good" fuel cell, I would expect it to be more efficient than a Stirling at converting the energy in its fuel to electrical power.

The Stirling does have a big advantage in its choice of fuel, however. Fuel cells need extremely pure, high grade fuel: hydrogen and methanol are the two that I've heard the most about. The Stirling, on the other hand, just needs a source of heat; from burning wood, coal or oil, from concentrated solar energy, from anything. There's never going to be a wood-powered fuel cell. You could take the wood, convert it to methanol, and use that to power your fuel cell. It could potentially still be more efficient than the Stirling, but you'd need to spend a lot to buy the refining and distribution equipment.

Micro Stirling engines:
A Stirling engine requires a temperature differential. I think it would be difficult to maintain this temperature difference across a really short distance. Heat insulation isn't good enough.

[Seeker]

quote:Originally posted by ftropea

This is one thing I've always wondered about... The idea of just plugging Stirlings wherever you have excess heat. I once proposed a sort of nanotechnological approach to utilizing the Stirling engine. Imagine tiny Stirling engines.. the cylinder a ring of atoms.. the piston made of some magnetic material. The outside of the cylinder is wrapped in a coil of copper atoms... as the working gas/atoms is being displaced, the magnetic piston moves up and down... The magnetic field interacts with the copper coil, producing electricity.

Now imagine millions of these nano-stirlings mixed with another conductive subtance - in the form of a "paint" and that this paint is applied to a surface.. This surface is conductive on one side and insulated on the other. The non-conductive side is bonded to a heat producing source, say the exterior of your car engine.. the conductive surface is connected to "leads" which pull the electrons away into a battery/capacitor...

The conductive surface is layered in an protective laminate.. protection from water.. scratches.. etc...

Just an idea floating in my mind...

Regards,

Frank A. Tropea


Hi Frank,

That idea sounds fasinating. Myself, I don’t know a whole lot about nanotechnology. The only thing I would wonder about is the heat loss effects you would experience at small sizes. You know like,as the size gets smaller, the surface area becomes larger, relative to the volume, and heat loss is proportional to surface area. But then this may be really only a factor if you’re comparing the heat loss of a large object to that of a smaller one. So it seems to me that if this kind of thing could be done cost effectively then it could be promising.

Another thing I wonder about is thermcouples. Don’t they have the ability to change heat into electricity ? Couldn’t they be used to convert the waste heat energy produced by devices such as computers etc, into electrical energy ? I’m thinking there must be some energy storage issues and cost issues that would come into play.

Seeker

[Seeker]

Relating to the idea of using the ‘thermocouple effect’ to change waste heat energy into electrical energy, I’ve posted some info and a link below :

Ya know... it seems like everyone is always working on valuable research projects , but it takes a long time to get a new technology to the point where it becomes useful. Don’t get me wrong, I know they’re trying their best, and probably making new advances all the time.

I guess that’s why 2 summers of research was enough for me.... :-)

Seeker



http://www.globaltechnoscan.com/31jan-6feb/generators.htm

quote:
The School of Engineering at Cardiff University has been conducting research into the conversion of heat energy into electrical power by means of the Seebeck effect. In principle, this involves utilising the properties of the thermocouple, which consists of two electrical conductors of different materials joined together at both ends. If the junctions are kept at different temperatures, an electric current is generated and flows through the conductors.


quote:
By linking together a large number of modern semi-conductor thermocouples in series, a sizeable current can be generated without any moving parts. For example, spacecraft like NASA’s Voyager deep- space probes rely on thermoelectric generators to provide all their on-board electrical power, and these devices were still performing to specification more than 14 years after launch and after a journey of more than a bullion miles.


quote:
Researchers have been wording on improving the efficiency of these devices, and reducing the cost of making them, to employ them over a wider range of applications. The first stage involved a detailed study of the materials used, to maximise the electricity output for a given heat source. Work was also done on the design and construction of thermoelectric generators to maximise their output and on the long-term behaviour of the materials, to predict their reliability.
Attention has also been turned to cheaper ways of making the materials used in thermoelectric generators, with the investigation of techniques like hot pressing, mechanical alloying and the deposition of materials from aqueous solutions. The overall objective is to develop devices which can produce useful amounts of electrical energy from low-temperature waste heat, which is otherwise very difficult to exploit as common by-product of many industrial processes.

[Seeker]

Frank,

I thought this technology had some similarities to the idea you were advancing :

quote:
The new material is a superlattice - a stack of very thin films of two alternating alloys. Each layer is a few millionths of a millimetre thick, and so contains just several dozen layers of atoms. The thermoelectric effect arises here because of the many heat-absorbing or heat-radiating interfaces - it is easier for a current to flow across an interface than for heat to pass across it.



quote:
The superlattices are also effective thermal scavengers. Their large thermoelectric effect means that a significant electrical current can be induced by very small temperature differences between one side of the sandwich and the other.


http://www.nature.com/nsu/011011/011011-12.html

Seeker

[don c.]

Micro heat engine cools hot processors

By Chappell Brown

ATHENS, Ohio -- Engineers at Sun Power Inc. are engaged in an ambitious micromachine research effort that aims to shrink cooling technology to the chip level.

If the project achieves its goal, a standard CMOS IC process could be used to fabricate a Stirling cycle heat engine on a microprocessor, promising a novel cooling method for electronics. The techniques could also be used to build high-temperature superconductor chips that could be packaged in the same way as any other room-temperature circuit.

"This has the potential to explode the number of applications for cold electronics," said project originator Lyn Bowman.

more: http://www.eetimes.com/news/97/973news/micro.html

[don c.]

http://www.cea.wsu.edu/P3_PRESSRELEASE/P3PRESSRELEASE.htm

The Very Little Engine that Could

Researchers at Washington State University have built the world’s smallest engine. It would fit inside the hole of a lifesaver and is thinner than a piece of paper. This tiny engine could replace batteries in many portable electronics. The researchers in the School of Mechanical and Materials Engineering and the Center for Materials Research have received a more than $7 million contract from the Army Space & Missile Defense Command (SMDC) together with sponsorship by the Defense Advanced Research Projects Agency (DARPA) to build the engine and to produce a portable micro-power generation system for military applications. With people’s increasing dependence on portable electronics, batteries have become increasingly problematic because they weigh a lot for the power they produce. The military has struggled with this problem, so that light infantrymen are required to carry an approximately 80-pound pack in the field, with 10 pounds of that load being batteries to power their electronics. Remote-controlled airplanes and robots are limited, too, by the heavy battery packs they have to carry. The logistics of re-charging batteries can also be difficult.

The engine, dubbed the P3, for Palouse Piezoelectric Power, is radically different in design, fabrication, and operation from any existing engine. Other researchers have tried to shrink large-scale internal combustion engines down to smaller sizes. The P3 is the result of a focused effort by the WSU team to entirely rethink the concept of an engine on the micro-scale. Instead of a machine shop this engine is manufactured in a cleanroom. The engine is fabricated from silicon using the same techniques developed by the microelectronics industry. And like the integrated circuit, thousands of identical copies of the same engine may be made in a single batch fabrication process.

Each engine can stand alone or be combined with other engines providing great flexibility in choosing the power output. From the low power, long duration missions of unattended sensors, to the high power short duration missions of micro air vehicles and robots, the P3 micro engine can be reconfigured on demand to meet the needs of many applications. Effectively the P3 is the integrated circuit of engines. Just as Intel puts thousands of circuits on a chip, the WSU team aims to build multitudes of engines together to offer users power by design.

The P3 micro-heat engine also provides great flexibility in the choice of fuel or energy source. The engine could run off a variety of sources, from diesel fuel to solar energy or even waste heat. So, for example, the P3 micro engine could produce electricity from the hot surface of a computer case or an exhaust pipe.

This new type of heat engine converts thermal power to mechanical power through the use of a novel thermodynamic cycle that approaches the Carnot cycle, which gives the potential for very high efficiencies. Mechanical power is converted to electrical power through the use of a thin-film piezoelectric generator.
The engine consists of a cylinder filled with a bubble and fluid sealed at the top and bottom by thin membranes. One membrane is a thin film piezoelectric membrane generator. As heat moves into and then out of the cylinder, the size of the bubble grows and shrinks, pushing on the piezoelectric generator. The piezoelectric membrane generates electrical charge as it flexes. By combining advanced materials, engineering, and design, the WSU team has developed a totally unique engine. Because of the potential for this device, the Washington State University Research Foundation has filed for patent protection for the device developed by the researchers, David Bahr, Bob Richards, and Cecilia Richards. The researchers are continuing with testing the first prototypes.

[ftropea]

Don - just when I thought I had an original idea ;)

Great find! You know, one thing about the Sunpower Inc. micro-Stirling is that it doesn't seem to be designed to generate electricity. It's being used more like a heat pump - either moving heat away from one area - or to an area - depending on the application. If they would make the pistons out of some magnetic material... and make the "cylinders" out of copper, for example, I wonder if that would be enough to produce electricity?

PS: Had to move this thread. I love the topic - but we're trying to keep threads in the Segway-HT forum which are directly related to the HT, and this one is "loosely" related... however, it's one of my favorite subjects.

Regards,

Frank A. Tropea

[Seg-wager]

This is fascinating! Thanks for the articles and links. Go for it, Frank! :)

[don c.]

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quote:
--------------------------------------------------------------------------------
Originally posted by ftropea

Don - just when I thought I had an original idea ;)

Great find! You know, one thing about the Sunpower Inc. micro-Stirling is that it doesn't seem to be designed to generate electricity. It's being used more like a heat pump - either moving heat away from one area - or to an area - depending on the application. If they would make the pistons out of some magnetic material... and make the "cylinders" out of copper, for example, I wonder if that would be enough to produce electricity?

PS: Had to move this thread. I love the topic - but we're trying to keep threads in the Segway-HT forum which are directly related to the HT, and this one is "loosely" related... however, it's one of my favorite subjects.

Regards,

Frank A. Tropea

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Frank, sorry, I didn't realize there was a 'Science and Technology' forum when I posted the above. I'll probably spend more time here until Kamen can get the Seg to fly, either literally or as a consumer product! :)

You are right, the Sunpower stirling is not an engine or electrical generator, it is configured as a 'cyro-cooler', meaning you input energy to derive a temperature difference (most often for cooling purposes), rather than inputting a temperature differential to produce mechanical output. This is the magic of electric motors and Stirlings, they each may translate (electric or temperature differentials, depending) energy, with mechanical energy. They are 'bidirectional'.

Cooling has probably been the most important use of Stirlings to date:

"there are Stirlings that touch our daily lives. The Stirling is bidirectional, that is, if temperature difference is applied, rotation is produced. But if rotation is applied, temperature difference is produced. So the Stirling makes a refrigerator. If you go to your local welding supply company and purchase liquefied gas (such as liquefied oxygen or liquefied nitrogen), it was made in a Stirling machine. When you watch the satellite weather pictures, they are courtesy of a tiny Stirling cryocooler, used in the satellite to cool the image sensor to near absolute zero."

from: http://www.qrmc.com/stirlinginfo.html

[Casey]

I had no idea Stirlings are being used to compress gasses for bottling. I wonder what the problem is with these machines that makes them unfit as engines for generating purposes.

[don c.]

quote:Originally posted by Casey

I had no idea Stirlings are being used to compress gasses for bottling. I wonder what the problem is with these machines that makes them unfit as engines for generating purposes.


Where have you heard that they were unfit? There are a few companies producing Stirling gensets for light industrial, RV, or in-home use, and several others pursuing the technology with or without Department of Energy grants.

http://www.whispergen.com/

http://www.stmpower.com/

http://stirlingtech.com/about/index.shtml

http://www.stirlingadvantage.com/intro.htm

http://www.babcock.com/pgg/tt/pdf/E1013120.pdf

[Casey]

quote:Where have you heard that they were unfit?

It isn't anything I've heard. But if these same engines are suitable for use as heat differential engines to run generators, I fail to see what the fuss is all about concerning Kamens version of the Stirling. I have read sites concerning the use of Stirlings for various purposes, and yet there seems to be this excitement surrounding Kamens engine being a breakthrough. I deduce from that, that the Stirlings already in use are not "ready for prime time".

[ftropea]

One aspect of Kamen's Stirling that may set it aside from other Stirlings is the potential to mass produce them, inexpensively - and of course all the optimizations and design innovations that are described in his patents. One that comes to mind is that "heat transfer" array of pins or fins.. that particular part able to be cast molded for example.

Regards,

Frank A. Tropea

[Casey]

Here is a quote from DK from a tour of his facilities that gives one reason for the Stirling problem.

quote:“Nobody here planned to invent new ball bearings, but in order to make this engine practical we have to develop a bearing technology that doesn’t exist,” he adds, as Levesque readies the machine to mold another bearing piece.


It is from an interesting demo tour available on this site. Click on Deans picture to take the tour.

http://www.technologyreview.com/articles/demo1002.asp

[don c.]

I'd say the company in the below article is well on the way to prime time:

http://www.powerco.com/Power/hpu/index.html

OCEAN POWER SIGNS $38MM PURCHASE AGREEMENT FOR HOME POWER UNITS

El Dorado Hills, CA, May 2, 2002: "Ocean Power Corporation (OTC BB Symbol: PWRE), Ocean Power Corporation is pleased to announce that it has signed an agreement establishing the conditions for sale of 10,000 3-kilowatt, Home Power Units (HPU) (http://www.powerco.com/Power/hpu/index.html), with a private real estate management company currently operating a portfolio of approximately 15,000 apartments. The HPU, which utilizes a Stirling engine is designed for use in multi-family apartment complexes and will be used to generate electricity, hot water and HVAC on-site. Ocean Power's HPU will provide environmental benefits by utilizing the (waste) heat from the unit to significantly increase overall system efficiency.

The systems will be installed in apartments during the normal rehabilitation process. The systems are sized so that after fulfilling tenants' needs they will provide excess electricity that will be available for sale to the grid. Ocean Power will participate with the management company in the on-going profits generated from the power sale, thereby building a recurring revenue base.

The average sale price for the first 10,000 units will be approximately $3,800 per unit. Delivery of the units will begin upon completion by Ocean Power of performance and code compliance certification, and installation is planned for completion by the end of 2005.

In addition to this order, the management company has entered into negotiations with Ocean Power for the exclusive marketing and distribution rights for multi-family dwellings in the United States. The U.S. multi-family dwelling market totals more than 20 million units.

"Clearly, the move toward decentralized power generation is the wave of the present", said Ocean Power's President Joseph Maceda. “Our Stirling HPU will be a commercially viable distributed generation product. The introduction of this product into the marketplace is a major step for Ocean Power in particular and distributed generation in general”.

Ocean Power is currently in discussions with other firms for the sale of the HPUs into the single family home market in the US and the single and multi-family markets in Europe, Asia, Canada, and Latin America."


Don't get me wrong, I am as interested in the outcome of Dean Kamen's Stirling as anyone (well, maybe not Brent VanArsdell or Darryl Phillips). I wouldn't be here otherwise. If he along with the engineering talent at DEKA Research produces a Stirling that has greatly improved energy efficiency, ease of use, and lowered manufacturing costs, that would be great. But I hardly think that the other players in the Stirling field, with products on the market, contracts in hand, and R&D efforts continuing, rank as "unfit".

[Casey]

That's what I'm waiting to filter down to Home Depot, Lowes etc for those of us ready to get into our own power generating. This holds an excitement for me that Segway doesn't. It's a truly practical and atmosphere friendly way to get rid of those horrendous power lines with their huge losses before the electricity even reaches it's destination.

I haven't gone to their site, but am interested to see if it is multi-fueled.

[don c.]

Some interesting stuff from Ocean Power's question and anwer page:

http://www.powerco.com/Power/hpu/hpufaq.html

Question 6: Are your engines of a proprietary design?

Answer. Yes, we do have advanced proprietary designs to boost engine efficiency and we are applying for patents. But more important is to win in the power marketplace with low-cost, high efficiency systems, because our competition is NOT other Stirling systems, nor fuel cells, nor other new sources of power. Our competition is the existing power infrastructure, and we intend to be cost-competitive within the current infrastructure; hence our focus on HPUs.

Question 7: Do you have patents similar to what DEKA has announced recently about their approach to high-speed manufacturing of advanced Stirling engine designs?

Answer. Yes. Our engines are covered under a number of patents and patents pending. These relate to both the engine itself and unique "hot end" technology dealing with combustion and heat transfer devices. These particular patents pending relate to a method of integrating multiple discrete components into a single monolithic structure that can be manufactured at extremely low cost. However, our approach to this issue is different from DEKA in that he is only dealing with heat transfer while we are integrating combustion functions as well. (Note: not sure this is true any longer, I believe Kamen has patents now pertaining specifically with combustion control)

Question 8: Could we have access to your engine for other applications besides home power? We accept that your ongoing negotiations may limit accessibility to your Stirling engines for the home power market, but given the low projected capital costs of your units, could we have access to your engine for other applications besides home power?

Answer. Yes. For further information regarding other applications of our advanced Stirling designs, please contact Joe Maceda.

Question 9: Does the $3,800 price holds for a system, which provides for cooling or refrigeration? A clarification: $3,800 is a very good price for a 3 kW electricity power output device with additional useful waste heat. As HPUs, are you implying that the $3,800 price holds for a system, which provides for cooling or refrigeration?

Answer. We project that the $3,800 average price is for a system with heat and electrical outputs. Additional costs would be incurred for a system to convert the waste heat for use in cooling or refrigeration.

[kamatahri_08]

hi! I'm a college student here in the Philippines and i'm really interested in this topic. i would just like to ask some questions regarding micro fuel cells for my research paper on alcohol micro fuel cells. here are some of my questions:

1. how do micro fuel cells recharge? do we need to supply or refil the alcohol manually? or they dont need refiling?
2. how do you measure energy generation of the alcohol in a micro fuel cell?

i hope someone here could help me in my research ASAP. thanks!


>>FaLL3n_AnG3L<<

[citivolus]

quote:1. how do micro fuel cells recharge? do we need to supply or refil the alcohol manually? or they dont need refiling?
They need to be refilled. All fuel cells work the same way. The alcohol is a means of storing protons effeciently. Storing the hydrogen as a gas would require very high pressures and it is much more compact as a liquid.

quote:2. how do you measure energy generation of the alcohol in a micro fuel cell?
I'm not sure what you mean. Fuel cells don't generate energy, they transform chemical energy into electrical energy. You would measure the power output directly in watts and the energy in joules or watt-hours. This should give you an overview.
http://www.howstuffworks.com/fuel-cell.htm

--
swiftly flying

[kamatahri_08]

thanks for the reply!

how much alcohol should be put for it to last for about 20 mins? and does anyone have an idea on what statistical method is appropriate in testing which alcohol is better if i have 2 alcohols that i would want to test? does the power output decrease linearly with time?

thanks again!

>>FaLL3n_AnG3L<<

[citivolus]

quote:Originally posted by kamatahri_08
how much alcohol should be put for it to last for about 20 mins?
That would depend on the power output. Wood alcohol has an energy density of about 16 megajoules per liter (MJ/l) and a regular engine at 20% conversion effeciency would be able to extract 3.2 MJ/l. If the liter is consumed in 20 min the best possible power output would be 2.67 kW or 3.6 horsepower. Now consider the efficiency of the fuel cell and adjust accordingly. If you can double your efficiency you use half the fuel, triple it and use one third.

quote:and does anyone have an idea on what statistical method is appropriate in testing which alcohol is better if i have 2 alcohols that i would want to test? does the power output decrease linearly with time?

I'm not sure what you mean by better. It will depend on what you are most interested in. Is it fuel consumption, cost, emissions, a list of other variables as long as the Nile river? Decreasing power output will depend on the fuel cell and its failure mode. I would think it would be possible to design it so that power drop was nearly linear as it ran out of fuel.

--
swiftly flying