Evolving fuel cell

[tvodrd]

Stumbled on this at NASA Tech Briefs. They are getting the operating temp way down:

http://science.nasa.gov/headlines/y2003/18mar_fuelcell.htm?list911586

 

[Lux Luthor]

Thanks.

Interesting article. I didn't know there was even a single hydrogen fueling station anywhere.

 

[Darell]

We have three H2 fueling stations here in Northern CA. Don't know about others. They're all private, and nobody will say how much they cost, or how much the fuel costs.

Right here is the statement the tickes me off the most in that article: "Key among these advantages is the ability to run on readily available fuels, such as methanol or even gasoline..."

Yup - step right up and run your electric car on gasoline! Ug. /ubbthreads/images/graemlins/frown.gif The story makes some good points and even mentions the chicken-and-egg problem that has plagued all types of EVs.

 

[binky]

Wow. That article's so full of ... well, a lot of marketing. I guess I can't blame them since they're just trying to do business in a crowded market sector, no wait, that's my tax dollars which bought that article and research. I can get annoyed!

How about this one:
[ QUOTE ]
By finding a way to build "solid oxide" fuel cells that operate at half the temperature of current designs--500°C instead of a blistering 1,000°C

[/ QUOTE ]
Doesn't that sound like all other fuel cells operate at 1,000°C? Well, they don't. I was stunned by that and others because I once did some debugging for Electrochem and their polymer fuel cells operate about 85°C. Sorta different, huh? A nice company, by the way, but I am biased.

Darell's spot on about the source of the fuel component too. It's not as though the H2 comes from trees. The most dense and least expensive way to get it is to liberate it from... oil and natural gas! And on top of that, nobody in the fuel cell industry mentions that because you've now added another step in the process, thermodynamic theory insists that there needs to be yet another loss in that conversion. Why not just burn the junk directly in your engine if you're gonna burn the junk? Dumb.

 

[zmoz]

Why do those electric and fuel cell cars allways have to look so stupid?!? /ubbthreads/images/graemlins/rolleyes.gif

 

[FreeBSDboy]

It's not dumb. Your car burning gas is only about 10% efficient at converting fuel to mechanical energy.

A PURE hydrogen fuel cell is more like 40%.

And don't confuse thermodynamics and chemistry. They chemically liberate hydrogen from hyrdocarbons (fossil fuels) using a catylist, usually platinum, which is quite efficient. I don't know the exact number, but it's a more efficient means of extracting usefull energy than burning it in an internal combustion engine.

So, your car liberating the hydrogen from the gas and combining it with the oxygen from the atmosphere to produce electricity extracts much more usefull energy from the fuel than simply burning it.

Fuel cell cars that run from reforming hydrocarbon based fuels are still more efficient that simple combustion.


It is also the first step in the evolution of the hydrogen economy. It puts fuel cells into everyday use. And eventually, when we figure out better ways to get energy than using fossil fuels (or maybe we just plain ran out--fossil fuels won't last forever), the hydrogen can be extracted from water instead.

 

[Darell]

[ QUOTE ]
zmoz said:
Why do those electric and fuel cell cars allways have to look so stupid?!? /ubbthreads/images/graemlins/rolleyes.gif

[/ QUOTE ]

Please let me know which of these Electric Cars looks stupid to you:

(...OK, I'll stop)

 

[Darell]

[ QUOTE ]
FreeBSDboy said:
It's not dumb. Your car burning gas is only about 10% efficient at converting fuel to mechanical energy.

A PURE hydrogen fuel cell is more like 40%.

[/ QUOTE ]
And a battery EV comes in at just above 90%. But that doesn't show the whole picture. We've left off the upstream inefficiencies. This is a tough one to argue, either way. But I agree that it would be cleaner to use the H2 that is extracted from gasoline than to burn it directly. But if we're going to have an electric car, why don't we work on the ones that won't require fossil fuels in the near-term?

 

[shiftd]

ehem Darell, it seems to me that the motorcycle one look a little bit out of ordinary. It just looks like as if the rider is bringing a whole box of soda cans right belom him. /ubbthreads/images/graemlins/grin.gif

 

[Steelwolf]

I remember reading about those fuel cells that run at 85degC when I was researching for a project. Most of the other fuels cells I read about for that project were all low temperature types ranging from the coolest at 85degC to the hottest at 250degC. I guess I must have missed the section with the 1000degC cell. Most of them were standard hydrogen cells, though quite a few had internal or external reformers so that natural gas, methane and other types of fuel which had carbon molecules could also be used. I believe the efficiency of those cells dropped if heavier fuel with more carbon was used. They were happiest with pure hydrogen.

It is true that upstream processes to convert hydrogen from oil and natural gas does add some losses to the overall process of converting fuel to motion. But we cannot take such a simplistic view. Fuel cells are efficient at converting fuel to electricity. This is the most important point. With an easily available supply of electricity in a compact and lightweight package, electric cars become a more viable option. Electric cars are good because you can easily convert the energy which would normally have been lost during braking back to electricity, which can be re-used when you get the car rolling again. This is probably where the greatest savings come from and why electric and hybrid cars all look so much more efficient than standard cars with internal combustion engines. Of course, electric motors are also more efficient than ICEs at converting energy to motion.

Finally, the matter of where the fuel comes from can also be tackled. There have been quite a few investigations about using sunlight to electrolyse seawater. Most of these studies show that it is an economic possibility as well as a technical possibility. Of course, the final problem of chicken and egg still remains. Who is going to do it when there is no demand? How do you build demand when there is no cheap and environmentally friendly source?

 

[FreeBSDboy]

[ QUOTE ]
Darell said:
And a battery EV comes in at just above 90%. But that doesn't show the whole picture. We've left off the upstream inefficiencies. This is a tough one to argue, either way. But I agree that it would be cleaner to use the H2 that is extracted from gasoline than to burn it directly. But if we're going to have an electric car, why don't we work on the ones that won't require fossil fuels in the near-term?

[/ QUOTE ]

In theory, yes, but in reality, no. Where do you think all the electricity comes from? Well mostly burning fossil fuels of course. Electric vehicles polute indirectly more than people realize. Although not nearly as much as conventional automobiles.

But I'm not going to argue electric vehicles versus fuel cells, because in reality they are closely related. Advancements in one technology can be applied to the other. The best outcome is a combination of the two. To quote Homer Simpson: "A little from column A, a little from column B"

Another part of the puzzle is power generation in general, but lets not get into that...

 

[Jonathan]

[ QUOTE ]
Steelwolf said:
I remember reading about those fuel cells that run at 85degC when I was researching for a project. Most of the other fuels cells I read about for that project were all low temperature types ranging from the coolest at 85degC to the hottest at 250degC. I guess I must have missed the section with the 1000degC cell.

[/ QUOTE ]

I believe the 1000degC numbers are only for the 'solid oxide electrolye' cells which are designed to run on hydrocarbon fuels _directly_, with no reformer at all.

The fuel cell need not be limited to the hydrogen-oxygen reaction. Molten carbonate fuel cells were explored which worked with carbon-oxygen, and a search on zinc-air fuel cells will turn up some interesting ideas, including a system that can be used as a battery (run current into it in order to charge it up) or as a fuel cell (replace the oxidized zinc with fresh zinc fuel).

The solid oxide fuel cells, if they can be made to run on bio-fuels, would be very interesting indeed.

-Jon

 

[binky]

[ QUOTE ]
FreeBSDboy said:
And don't confuse thermodynamics and chemistry. They chemically liberate hydrogen from hyrdocarbons (fossil fuels) using a catylist, usually platinum, which is quite efficient. I don't know the exact number, but it's a more efficient means of extracting usefull energy than burning it in an internal combustion engine.

[/ QUOTE ]

Hmmm. It's an interesting point about the chem vs burn efficiency. I don't think I was confusing chem vs. thermo, though since in both cases it's an enthalpy loss involved? I like your approach to the considerations. I wonder about the energy required to mine the catalyst too, by the way, although I recognize that platinum is already beneath me in the converter behind my Honda engine so maybe it cancels out. I'll look into it some more before I mouth off again. Probably. Maybe. Heh heh. /ubbthreads/images/graemlins/wink.gif

 

[Darell]

[ QUOTE ]
FreeBSDboy said:
[ QUOTE ]
Darell said:
And a battery EV comes in at just above 90%. But that doesn't show the whole picture. We've left off the upstream inefficiencies. This is a tough one to argue, either way. But I agree that it would be cleaner to use the H2 that is extracted from gasoline than to burn it directly. But if we're going to have an electric car, why don't we work on the ones that won't require fossil fuels in the near-term?

[/ QUOTE ]

In theory, yes, but in reality, no. Where do you think all the electricity comes from? Well mostly burning fossil fuels of course. Electric vehicles polute indirectly more than people realize. Although not nearly as much as conventional automobiles.

[/ QUOTE ]
I'm sorry, I can't let this go. Let's first compare H2 with battery. If an H2 uses 4x the electricity than does battery, then it doesn't matter how dirty the electricity is, if the source for both technologies is the same. H2 WILL be more polluting in that case.

If we compare battery to gasoline - there is NO way to get gasoline cleanly. 100% of the electricity used to charge my car is renewable or "clean." No coal or oil is burned to fuel my car. In fact, if I were using fossil-fuel-fired plants, I'd make the plants more efficient by charging off-peak on "wasted" energy when the load needs to be balanced. How then, does my EV pollute more than I realize? The secret here is how much an ICE pollutes that people don't realize. The entire upstream situation is dirty. It takes TONS of electricity even to make gasoline. Anybody count that big ugly pollution before the gasoline even gets into the car?

I've been over this lots of times in other threads, so I won't go into it deeper here.

 

[Darell]

[ QUOTE ]
Steelwolf said:
Electric cars are good because you can easily convert the energy which would normally have been lost during braking back to electricity, which can be re-used when you get the car rolling again. This is probably where the greatest savings come from and why electric and hybrid cars all look so much more efficient than standard cars with internal combustion engines. Of course, electric motors are also more efficient than ICEs at converting energy to motion.

[/ QUOTE ]
Regenerative braking can, at best, account for only about 10% gain in efficiency. Not insignificant, but also not the biggest reason that EVs are so efficient. I put over 90% of the power in my battery pack to the pavement. An ICE is lucky to put 15% there. That's BEFORE you start talking about regenerative braking. The energy losses in heat, friction and sound are giant. And you don't get to burn gas efficiently at all RPMs and loads. Can't be done... not with today's technology. An EV at peak efficiency at every speed. My car holds about the equivalent of one gallon of gasoline energy it its batteries. With that gallon of gas equivalent, I can travel about 120 miles even without using the brakes. /ubbthreads/images/graemlins/smile.gif

 

[FreeBSDboy]

Darell, I must apologise, I must not have read your post well enough. After re-reading it I think I missed the part about upstream inefficiencies, which was the point I was trying to make.

And I'm not trying to argue H2 Vs. electricity. There are strengths and weaknesses inherent in each, but they are both better than what we have now. I think the ideal vehicle would be a hybrid of the two. Batteries / off-peak charging for short trips, hydrogen for the busy days and the long hauls.

And of course climate and your environment have a lot to contribute too. What works well in California may not work well in New England. As much as I'd love to have a clean electric car, I just couldn't use it here in NH. For that matter the current crop of fuel cells is also inadequate for my needs. I frequently take long trips to northern VT in the wintertime and it regularly gets down to 20 below zero, where both technologies start to have problems.

But I digress. Solid oxide fuel cells, for which this thread was originaly started, have more of an application for infrastructure as opposed to in vehicles. I think we may have strayed a bit from that fact.

 

[Darell]

[ QUOTE ]
FreeBSDboy said:
But I digress. Solid oxide fuel cells, for which this thread was originaly started, have more of an application for infrastructure as opposed to in vehicles. I think we may have strayed a bit from that fact.

[/ QUOTE ]
Guilty as charged, as usual. I quite agree with your thinking here, and have always said so. I only have issues with FCs as mobile power sources.

I'll shut up for a bit. /ubbthreads/images/graemlins/smile.gif

 

[Brotherscrim]

[ QUOTE ]
FreeBSDboy said:
To quote Homer Simpson: "A little from column A, a little from column B"



[/ QUOTE ]

ahem. it was Abe Simpson who said that. I'm sorry, but that glaring error was simply too great for me to ignore.

 

[FreeBSDboy]

Doh!