Interesting engine?

Ben Hallert wrote:

...

That said, I don't understand what the bourke engine is supposed to do
different to get the numbers it describes, like another poster
mentioned, it looks like a two cylinder rotary.


ITYM 'radial'. I make the same mistake in conversation all the time.

--

FF

Just wanted to make sure.

I got your post mixed up w/ Marc's. Sorry.

Note to self: Don't try to post when you didn't have enough rest.

Someone said

By coincidence, the energy in a gallon of liquid H2 is in the same
ball park as a gallon of gasoline, so figure a 50 gallon tank. But a
gallon of liquid H2 is just over 1/2 pound -1/12th the density of
gasoline. That - and the need to keep it at minus 423 degrees F-
makes for some interesting design tradeoffs. ;^)


Can someone post a cite? Everything I can find suggests a gallon of liquid hydrogen has much less energy than a gallon of even automotive gasoline. I'm not quibbling, I'm really just interested in knowing the specifics. Thanks.

On Tue, 6 Dec 2005 12:31:29 +0000, Chris Wells
wrote:


Someone said

By coincidence, the energy in a gallon of liquid H2 is in the same
ball park as a gallon of gasoline, so figure a 50 gallon tank. But a
gallon of liquid H2 is just over 1/2 pound -1/12th the density of
gasoline. That - and the need to keep it at minus 423 degrees F-
makes for some interesting design tradeoffs. ;^)


Can someone post a cite? Everything I can find suggests a gallon of
liquid hydrogen has much less energy than a gallon of even automotive
gasoline. I'm not quibbling, I'm really just interested in knowing the
specifics. Thanks.

You hit a topic that I've just been researching and I have never seen
so many *different* results from comparisons or such bias in studies.
The only thing with more conflicting results and promises was Alcohol.

But I can give you a few specifics which should be undisputed.
First, to directly answer your question: A gallon of gasoline has
about 120,000 BTUs, A gallon of liquid hydrogen has about 30,000 BTU,
so it takes 4 gallons of liquid hydrogen to equal the energy in a
gallon of gas. So the weight savings although substantial is not
nearly as much as it appears.

*OTOH* I believe (I'm trying to relocate the source of that one) an
engine running on straight H2 can be about twice as efficient as one
burning gas. (this is not quite as straight forward as it sounds),
but that means we only need half as much fuel to go the same distance.

"In general" the industry thinks of Hydrogen like a battery, rather
than a fuel. It is an intermediary where you put in energy to make H2
and then you get the energy back out.

Like charging a battery it takes more energy to make Hydrogen than you
can get back out of it. It is difficult to make and costly depending
on the method used.

Proponents like to cite esoteric ways of making hydrogen that cost
little, such as wind and solar energy, but those are only dependable
in a few geographic areas. They forget that the installation of a
suitable solar array is quite expensive and depending on location the
maintenance can also be expensive. Wind generators are not cheap
either.

So in reality it's expensive and it's difficult to store in quantity,
but there is some promise in using metal hydrides as metal sponges.
Unfortunately you just lost the weight advantage when using metal
sponges for storage.

Like electricity, the energy to create the Hydrogen has to come from
some where and there just aren't that many places where solar and wind
are dependable and/or predictable.


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

On Sun, 04 Dec 2005 22:24:55 -0800, Richard Riley
wrote:

On Mon, 05 Dec 2005 02:30:09 GMT, "Capt.Doug"
wrote:

:"Richard Riley" wrote in message
: OTOH, I'm doing some work now with a V6 that's getting an SFC of .05.
: But that's on pure hydrogen, so the fuel system ends up a little
: involved.
:
:How big would the hydrogen tank be for a C-172?
:
.

By coincidence, the energy in a gallon of liquid H2 is in the same
ball park as a gallon of gasoline, so figure a 50 gallon tank. But a

No, the energy in a gallon of Hydrogen is no where near the energy in
a gallon of gas. A gallon of gasoline has
about 120,000 BTUs, A gallon of liquid hydrogen has about 30,000 BTU,

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
gallon of liquid H2 is just over 1/2 pound -1/12th the density of
gasoline. That - and the need to keep it at minus 423 degrees F-
makes for some interesting design tradeoffs. ;^)

On Tue, 06 Dec 2005 22:46:28 -0500, Roger
wrote:

On Tue, 6 Dec 2005 12:31:29 +0000, Chris Wells
wrote:


Someone said

By coincidence, the energy in a gallon of liquid H2 is in the same
ball park as a gallon of gasoline, so figure a 50 gallon tank. But a
gallon of liquid H2 is just over 1/2 pound -1/12th the density of
gasoline. That - and the need to keep it at minus 423 degrees F-
makes for some interesting design tradeoffs. ;^)

Remember fuel prices change rapidly and over a wide range so many of
these articles may be a tad out of date already.

http://www.switch2hydrogen.com/h2.htm for a fresh if not realistic
approach for most of us. Note the car uses tanks of metal hydride to
hold/store the Hydrogen safely.

Can someone post a cite? Everything I can find suggests a gallon of
liquid hydrogen has much less energy than a gallon of even automotive
gasoline. I'm not quibbling, I'm really just interested in knowing the
specifics. Thanks.

See the above link and http://en.wikipedia.org/wiki/Hydrogen_car
where they are using metal hydride sponges to hold the Hydrogen
safely. Note they talk about free fuel, but not the cost of
installing the system which is a long way from being cheap.

I think some confusion comes from the way the energy is stated.
Hydrogen does have the highest energy per unit weight, but not volume
and Hydrogen is far lighter even in liquid form than other fuels. It
appears to depend on what image a company wishes to convey whether
they rate the energy in unit volume of weight.

I should have included these in the original post.
As far as range the car "claims" a range of about 250 miles on the
Hydrogen it carries. I'm not sure how many tanks or how much weight
that would add up to. The engine is a dual fuel in that when it runs
out of hydrogen it switches to conventional gas.

Hydrogen and high compression do not mix well either in gas type
engines, but works great in diesel as pre ignition is no longer a
problem. However with high compression come nitrides as pollution.

In general, Hydrogen is considered expensive and would be in most
cases.


BTW, I've always been under the impression that Alcohol had a low
octane rating, but it's about 115 measured in the same manner as car
gas. You see all kinds of claims, but the true cost is about $2.40
something a gallon.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
You hit a topic that I've just been researching and I have never seen
so many *different* results from comparisons or such bias in studies.
The only thing with more conflicting results and promises was Alcohol.

But I can give you a few specifics which should be undisputed.
First, to directly answer your question: A gallon of gasoline has
about 120,000 BTUs, A gallon of liquid hydrogen has about 30,000 BTU,
so it takes 4 gallons of liquid hydrogen to equal the energy in a
gallon of gas. So the weight savings although substantial is not
nearly as much as it appears.

*OTOH* I believe (I'm trying to relocate the source of that one) an
engine running on straight H2 can be about twice as efficient as one
burning gas. (this is not quite as straight forward as it sounds),
but that means we only need half as much fuel to go the same distance.

"In general" the industry thinks of Hydrogen like a battery, rather
than a fuel. It is an intermediary where you put in energy to make H2
and then you get the energy back out.

Like charging a battery it takes more energy to make Hydrogen than you
can get back out of it. It is difficult to make and costly depending
on the method used.

Proponents like to cite esoteric ways of making hydrogen that cost
little, such as wind and solar energy, but those are only dependable
in a few geographic areas. They forget that the installation of a
suitable solar array is quite expensive and depending on location the
maintenance can also be expensive. Wind generators are not cheap
either.

So in reality it's expensive and it's difficult to store in quantity,
but there is some promise in using metal hydrides as metal sponges.
Unfortunately you just lost the weight advantage when using metal
sponges for storage.

Like electricity, the energy to create the Hydrogen has to come from
some where and there just aren't that many places where solar and wind
are dependable and/or predictable.


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

But I can give you a few specifics which should be undisputed.
First, to directly answer your question: A gallon of gasoline has
about 120,000 BTUs, A gallon of liquid hydrogen has about 30,000 BTU,
so it takes 4 gallons of liquid hydrogen to equal the energy in a
gallon of gas. So the weight savings although substantial is not
nearly as much as it appears.

Except a gallon of liquid H2 weighs much less than a gallon of gas.


Proponents like to cite esoteric ways of making hydrogen that cost
little, such as wind and solar energy, but those are only dependable
in a few geographic areas. They forget that the installation of a
suitable solar array is quite expensive and depending on location the
maintenance can also be expensive. Wind generators are not cheap
either.


A few geographic areas? That's hardly an accurate statement. Not only has there been an explosion in the growth of solar & wind energy, there are vast areas of the earth, far from human habitaion, where both forms could be used to produce hydrogen which could be shipped in hydride or some other form by robots in the near future. Also, wind energy is one of the cheapest forms of energy at the moment, and it's getting cheaper. There are other forms of renewable energy, and energy storage technologies, that though relatively unknown, have vast potential - such as wave energy and air compression.

No energy technology will single-handedly save us from our problems, but a combination of conservation and resource management can enable us to provide all of our energy needs with renewables, not that it would be necessary (or possible) to stop all fossil fuel use.

Chris Wells wrote:

...

Proponents like to cite esoteric ways of making hydrogen that cost
little, such as wind and solar energy, but those are only dependable
in a few geographic areas. They forget that the installation of a
suitable solar array is quite expensive and depending on location the
maintenance can also be expensive. Wind generators are not cheap
either.


A few geographic areas? That's hardly an accurate statement.

True. The actual statement was "...but those are
only dependable in a few geographic areas. "

And it is quite true because over most of the Earth
winds and clouds are highly variable.

Not only
has there been an explosion in the growth of solar & wind energy, there
are vast areas of the earth, far from human habitaion, where both
forms could be used to produce hydrogen which could be shipped in
hydride or some other form by robots in the near future. ...

Which also provides a buffering effect compensating for that
variablity.

--

FF

On Thu, 8 Dec 2005 15:57:46 +0000, Chris Wells
wrote:


But I can give you a few specifics which should be undisputed.
First, to directly answer your question: A gallon of gasoline has
about 120,000 BTUs, A gallon of liquid hydrogen has about 30,000 BTU,
so it takes 4 gallons of liquid hydrogen to equal the energy in a
gallon of gas. So the weight savings although substantial is not
nearly as much as it appears.

Except a gallon of liquid H2 weighs much less than a gallon of gas.

I already said that. I also mentioned that an engine running on
Hydrogen can be almost twice as efficient as an internal combustion
engine running on gas.


Proponents like to cite esoteric ways of making hydrogen that cost
little, such as wind and solar energy, but those are only dependable
in a few geographic areas. They forget that the installation of a
suitable solar array is quite expensive and depending on location the
maintenance can also be expensive. Wind generators are not cheap
either.


A few geographic areas? That's hardly an accurate statement. Not only

I stand by the statement as fairly accurate, but I will change it to
say a few handily accessible areas.

has there been an explosion in the growth of solar & wind energy, there
are vast areas of the earth, far from human habitaion, where both

The explosion in growth still leaves it as only a token in size.

Far from human habitation makes them expensive due to the added
requirements of storage and shipment. However as I understand it you
can get more hydrogen into a given volume of hydrides than you can
liquid hydrogen into the same volume. I have a bit of trouble
understanding the physics of that one, but I read it on the net so it
must be true. :-)) However when you scale up the generation and
shipment you bring a whole new set of problems and costs into the
equation.

If you use the electricity directly from the wind generators it would
have to be a very large scale operation to justify the power
transmission lines if it is very far from populated areas which again
would make it expensive. At least the Hydrogen could be done on a
smaller scale and would be easier to scale up in smaller steps.

Take for instance Alcohol. The best places for growing crops/bio mass
to produce Alcohol in the US are in the southern states. However the
ability to produce biomass is limited by both geography and economic
conditions. How much productive land can be taken out of regular
production to produce biomass before it impacts the cost of other
crops and the availability of food? Brazil has already run into this
problem and they produce Alcohol from sugar cane. They have the ideal
climate and the ideal crop and they have an Alcohol economy.
Unfortunately it has already caused some severe economic problems.

forms could be used to produce hydrogen which could be shipped in
hydride or some other form by robots in the near future. Also, wind

They aren't going to be shipped by robots in the near future. Local
labor would howl like mad were the equipment available, but the
technology (both wind and solar) is expensive to implement and you are
talking Hydrogen in *quantity* which becomes a whole different animal.
You really need to live in an area where solar or wind is viable and
close to produce Hydrogen on a small scale.

energy is one of the cheapest forms of energy at the moment, and it's
getting cheaper. There are other forms of renewable energy, and energy

That is true, but there are so many places where it is not a viable
source. Take Michigan for example. Although there are a few working
wind generators and we have the ideal average wind of 8 mph, we have
long periods of little or no wind and periods of high winds to get
that average. Neither the high winds or calm are of much use in power
generation. At least the newer generators are not nearly as noisy as
the old two bladed ones. Those things were loud!

storage technologies, that though relatively unknown, have vast
potential - such as wave energy and air compression.


So far, air compression is not viable on a large scale and it's a very
lossy (large negative net power gain), but water being pumped to a
higher elevation (potential energy) is much more efficient. It's also
being used as a storage medium here in Michigan by at least one power
plant on Lake Michigan. The problems with these storage methods is
they take more power then they give back so they are used during slack
times to store excess energy. All forms of energy storage have a
negative, net power gain. Hydrides, and Hydrogen storage are probably
the most efficient, but they are not exactly light weight or cheap
Wave energy is a method of power generation rather than storage unless
we are talking about two different things.

Even if you could produce the Hydrogen for free the equipment for
transportation and storage would make it an expensive fuel.
*Eventually* the prices would probably come down when Hydrides are
available on a large scale, but again it most likely would take
decades. I say hydrides as they are currently about the only safe way
of storing large amounts of Hydrogen in a hostile environment (the
highway) They are actually much safer than cars using gas.


No energy technology will single-handedly save us from our problems,
but a combination of conservation and resource management can enable us
to provide all of our energy needs with renewables, not that it would be
necessary (or possible) to stop all fossil fuel use.

Here we are in agreement, but I see the adoption of alternative fuels
on large scale as being quite a ways off and "on the average" they are
still well above the cost of regular gas. From what I've read in the
last few weeks puts the cost of gas, on average at roughly $2.50 to
$3.00 a gallon before the alternative fuels can become a viable
alternative. When subsidies are figured in that is just about the cost
of a gallon of Alcohol ($2.46).

I think the adoption of alternative fuels and energy sources on
anything other than a token scale or localized such as the wind farms
in California and Japan is more than a decade off and most likely even
a couple of decades or more. I wish it were sooner, but the more I
study it the farther off it seems.

As to conservation: If every car and truck on the road could cut
their consumption by a third (33%) by what ever means, we'd probably
no longer have to import oil.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com