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Hydrogen Fuel Cells!

Former Member
Former Member

Hydrogen fuel cells (in particular PEMFCs) are an exciting technology which has been around for a while now. Unfortunately, they haven't really take off (excuse the pun) due to their high cost, poor lifetime and slow transient performance.

 

1. So why are people still interested?

 

Well, firstly you have the good old "clean & green" argument. In operation, the take in oxygen (from the air) and hydrogen (the fuel), and give out heat, water and electricity. No carbon dioxide, monoxide, sulfides and other nasty things.

Secondly, they're not dependent on fossil fuels to run, and are currently the most promising energy generation technology that is independent of the elements (wind, solar, etc).

Hydrogen has a superb energy density, meaning not much weight gives you a huge endurance.

Fuel cells tend to have no moving parts, unless the have a cooling fan or air supply fan, so they are mechanically very simple.


2. So why aren't we using them?

 

They require platinum as a catalyst so make the chemical reactions work. Platinum is incredibly expensive, and more annoyingly it tends to be washed away over time which reduces the fuel cells lifespan.

They are slow to respond, so cruising along at 10% power, then suddenly demanding a full 100% may take anything from seconds, to minutes, to hours, depending on the type of fuel cell. This proves a big challenge in mechanical transport, such as planes, and cars.

Hydrogen is a pain in the rear, generally. To produce the high quantities we need, we can only do it (cost-effectively) by burning fossil fuels. Of course it can be generated using renewables (wind, solar, etc), but this is far too expensive at the moment for the industry to consider.

Hydrogen also is a pain to store. Because there are so few molecules in such a large amount of space (low density), you have to store it at tremendous pressures to get a usable quantity, which requires huge storage tanks. Not particularly practical in transport applications. There are other methods, but cost and practicality is still a huge issue.

 

3. Where do I fit in?

 

To start I am not a chemical engineer. However, I am a PhD researcher for the Hydrogen Fuel Cells & their Applications Doctoral Training Centre (DTC) in the United Kingdom, so I know a fair amount about it. By trade I am a autonomous control engineer, specialising in unmanned aerial vehicles (UAVs).

Given all the problems outlined above, even the suggestion of putting a fuel cell on a small UAV, which is essentially a modified off the shelf remote controlled hobby plane, seems crazy. But it is do-able, and has been done. The advantages for flight aren't the clean & green approach currently dominating the selling point of fuel cells, but that key word "endurance". To fly for 10 hours, a UAV would have too many batteries to float, let alone fly, but with hydrogen's energy density this may well be possible. That's what I'm going to find out.

 

4. So that's nearly 500 words with no raspberryPi?

 

Haha, hopefully I have set the scene now. Let's talk about the electronics!

The fuel cell is a dumb system. It's just a contained and continuous chemical reaction. But it can be controlled through the hydrogen supply, the load and the temperature. I can overcome the poor transient performance if I know that "soon" I will need full power; I can simply crank the fuel cell up, dump the excess power, then when the time comes, 100% is there to give. Sounds wasteful, but it turns this fuel cell into something useful. To control the logic we need a computer. On a small UAV the raspberryPi is ideal, in terms of size, power (in & out), flexibility and functionality.

Running a Real Time Operating System (RTOS) is a seriously useful tool, which I could not do on my work last year (using Arduino). I can programme in any language, use other peoples software (eg the camera) and share my code with the world (and myself for backup!) on GitHub.

So far I am using several add-ons including the MATLAB/SIMULINK support (to help the academics!), rPi Camera, delta-sigma-pi I2C ADC, piFace SPI Digital IO, TMP102 I2C temperature sensors and have the whole lot connected to an onboard UAV autopilot.

 

At risk of making this essay any longer, I'll wrap up now. I hope this is something that tickles your interest, and keep tuned for some videos, pictures tutorials and demos in the coming weeks. In the meantime, if you are interested in the plane the check out my page on diydrones.

 

Simon

_________________________________

S HOWROYD MEng (Hons) RAFVR(T)

Academic Researcher

Fuel Cells in Unmanned Vehicles

Autonomous Systems Specialist

Aeronautical & Automotive Engineering

Loughborough University

 

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Parents

  • I like the idea of hydrogen to be used as fuel but its combustible nature is too risky.

     

    Still it is a clean fuel that we need to tap into.

     

    If I am not wrong liquid hydrogen does work as fuel but again the same issue .

     

    ITS RISKY.

     

    I however think that still it can be used.

     

    The best ways of using hydrogen as fuels that I can think of is if as already provided today is cryogenic chambers.

     

    I propose minute hydrogen packets the size of gelatin pills.

    One pill can store as much compressed liquid hydrogen it can as specified.

    And all the pills will be kept together in a huge chamber instead of the whole content being put in the cryogenic chamber.

    A small auto dropping system can be made which will release one pill at a time to outside temperatures and when hydrogen pill react to regular temperatures at a fast rate we know what happens Combustion.

     

    I will try to formulate a system for this.

     

    But need to work on trapping compressed liquid hydrogen in small gelatin packets.

     

    That I leave it in your hands.

    The system however can be made according to safety standards and hydrogen explosion force and thereby viable. to all image

     

    TC till then
    image
    P. KISHORE KUMAR

Comment

  • I like the idea of hydrogen to be used as fuel but its combustible nature is too risky.

     

    Still it is a clean fuel that we need to tap into.

     

    If I am not wrong liquid hydrogen does work as fuel but again the same issue .

     

    ITS RISKY.

     

    I however think that still it can be used.

     

    The best ways of using hydrogen as fuels that I can think of is if as already provided today is cryogenic chambers.

     

    I propose minute hydrogen packets the size of gelatin pills.

    One pill can store as much compressed liquid hydrogen it can as specified.

    And all the pills will be kept together in a huge chamber instead of the whole content being put in the cryogenic chamber.

    A small auto dropping system can be made which will release one pill at a time to outside temperatures and when hydrogen pill react to regular temperatures at a fast rate we know what happens Combustion.

     

    I will try to formulate a system for this.

     

    But need to work on trapping compressed liquid hydrogen in small gelatin packets.

     

    That I leave it in your hands.

    The system however can be made according to safety standards and hydrogen explosion force and thereby viable. to all image

     

    TC till then
    image
    P. KISHORE KUMAR

Children
  • in reply to rodreig89kishore

    Hi Kishore,

     

    Hydrogen is actually much safer than current gasoline and easier to use than ethanol.

    Most of the hysteria stems from the vivid pictures of the Hindenburg, but analysis has shown that it was the cloth coating that caused the fire, not the hydrogen.

    However, you just cannot fight public perception.

    I use natural gas to heat my house and hot water.  It is very safe, inexpensive and I look forward to buying a vehicle that runs on natural gas.

    I would worry more about the Lithium Battery fires than I would hydrogen.

     

    Your gelatin solution will probably not work.  Hydrogen is very reactive with most polymers and has been known to pass through most materials except dense containers.

     

    Just a thought,

    DAB


  • Former Member
    Former Member in reply to rodreig89kishore

    Hi Kishore,


    Liquid hydrogen is a whole world of issues due to it's boil off and therefore safety due to over-pressuring. This is the "risky" nature of hydrogen you talk about. Not to get confused with hydrogen being flammable as the main risk because every fuel is flammable! Hydrogen is surprisingly safe. In terms of fires, there is a well known experiment (although I can;t find the paper it's from now) but the images are here, showing the difference between a petrol fire and a hydrogen one in a car. As I understand, they doped the fuel to ensure it produced a coloured flame, as a hydrogen flame is normally invisible. In general, and with todays techniques, hydrogen tanks are way over safe, tasted in stupid situations, not because it's needed in engineering but more to overcome this public perception that hydrogen is more dangerous than anything else.


    You mention hydrogen explosions, this will be of two forms; either an overpressurised tank (due to boil off in a liquid store), or a hydrogen + oxidiser mix in the tank (like a space rocket), which never happens in fuel cells as impurities in the hydrogen damage the cell.


    If you are interested in the storage of hydrogen, in particular for portable applications, you need to look at either 350-700bar compressed gaseous hydrogen, or a metal hydride (or metal organic framework). Keeping hydrogen a liquid would be approaching impossible, without a vent and then we'd have car parks full of hydrogen & air mixed...no smoking!


    DAM: just a word to yourself. Thanks for your comments, I can see you are also knowledgeable in the area, great to hear! My car runs on propane (autogas) at the moment. It's great, I am a big fan of natural gas, particularly in solid oxide fuel cells (SOFCs) where they can increase efficiency from burning at 20% to the fuel cell method of 50-60%, even higher if you use the waste heat in a combined heat and power (CHP) system. The only issue is that it isn't renewable, but a move from 20% to even 40% efficiency would double the life of the supply!


    Simon

  • in reply to Former Member

    Hi Simon,

     

    I dabble in a lot of technology areas.

    We should soon have more efficient processes for energy extraction and conversion.

    My new book. "I Killed Schrodingers Cat!," will open many new research areas into how we can manipulate atoms and charge transmissions to much higher efficiencies.

    So keep watching, we are about to enter a new era.

     

    DAB


  • in reply to Former Member

    TY image Simon for giving more insight on Hydrogen.

     

    All I used was basic stuff to formulate such notion. I am glad and humbled by your opinion.I need more info on it to learn more on it.It is good that you have the knowledge and I don't
    To learn is my ultimate goal.:D
    You mentioned about a paper.Can you mail it to me.
    I would love to study more on this subject.
    I like the environment cleaner, better, and more efficient. image
    Please keep me posted. image

    Thank You.


    P.KISHORE KUMAR

  • in reply to DAB

    True that DAB. We cannot fight public hysteria.

     

    If I am not wrong it must be the hysteria that mixed with true facts that led me to believe that hydrogen is a much dangerous gas than it is.
    Well you cleared another doubt too. Gelly wont work. image

     

    Well that is another start for me then.
    TY for your input DAB.

     

    I like to learn more.
    Now that my notion has been dispelled about hydrogen  I'd like some more info on it.

     

    Wikipedia and Google search doesn't make the cut. lol image
    I would like to find more solutions for the environment.

     

    Keep feeding me the info. Learning is what I do.

     

    To protect the environment that I love the most. image

     

    Thank You DAB again.

     

    P. KISHORE KUMAR