Washington Post: Autobahn Deaths Force Germans to Rethink Passion for Speed
Mar 4th 2004, 12:12 am
#76
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths ForceGermanstoRethinkPassion
On 4/03/04 13:19, in article [email protected], "Keith
Willshaw" <[email protected]> wrote:
> What you need to measure is what is the ratio between energy
> released in combustion of the fuel and the energy delivered
> at the power socket. This is termed the electrical efficiency and
> is typically in the range 14-35%. The VERY best figure I have
> seen was produced by the German Scwarze Pumpe power plant
> near Dresden which when new operated at 41% electrical efficiency
> at point of distribution
>
> For a modern gas turbine power plant the figure is typically in the
> 30-35% range at full power
>
> Diesel engines are typically around 35-45% with spark ignition
> engines 27-40%
It is the upper limit on the gasoline engines that appear strange.
What is the median value for new cars on the road? The 25% figure
is what I have in my mind. The 40% looks like some odd duck
extreme figure. I am looking for "typical".
> the thermodyanmic trap of heat engines.
>
> Not really. You need to produce, store and distribute the H2
> used by the fuel cells and that is typically done by the steam reforming
> of natural gas (a process producing LARGE amounts of CO2) or
> electrloysis.
Obviously the dream is generating the H2 from sunlight when
in fact there is no real industrial way of doing that now.
I discount the hydrogen economy if it is based on the transport
and storage of H2. I find the danger level too high.
Any of the ecological solutions has to avoid releasing more CO2
into the atmosphere to be political correct.
> This turns out to be LESS efficient than using the natural gas
> to drive closed cycle gas turbines.
>> Over all chemical to electrical energy conversions should reach the
>> practical level of 80%.
>
> No Mam. The electrical efficiency of most fuel cells is closer
> to 45% due to losses in fuel reformer, the cell stack, the inverter
> and the auxiliary equipment.
Are you saying that the H2/O2 fuel cell is 45% efficient? You used
the term "most". I thought the number of really operational fuel
cells low. The literature says efficiencies in the 40-70% range and
you chose the low range limit? If you a list with their efficiences
that might prove instructive. My figure of 80% has the caveat
"should reach".
> >> The problem is, of course "the fuel cell", what fuel cell? The hydrogen
>> economy proposition has it own set of problems, I would not like to
>> fool around with stored (in whatever form) hydrogen gas. One proposition
>> is to go over to a methanol economy, using it as the carrier, for which,
>> I understand, there exists now a good fuel cell.
>
> Methanol of course is also an excellent fuel for conventional
> spark ignition engines but you must first produce your methanol
> which has its own problems.
The goal here would be a sustainable non-fossil fuel source, which means
biological right now, like from wood. Industrially methanol is obtained from
methane which is a fossil fuel (we think!). Even now, conversation of H2 in
methanol would be better than direct use of H2, for transport reasons.
Whatever, photosynthesis is just reversed combustion, CO2 + H20 => (CH2=O)x
+ 02 and use of sunlight is the eventual key. It is where fossile fuels came
from and if man is so smart, he should be able to figure out a practical
way of doing the same thing.
Earl
Willshaw" <[email protected]> wrote:
> What you need to measure is what is the ratio between energy
> released in combustion of the fuel and the energy delivered
> at the power socket. This is termed the electrical efficiency and
> is typically in the range 14-35%. The VERY best figure I have
> seen was produced by the German Scwarze Pumpe power plant
> near Dresden which when new operated at 41% electrical efficiency
> at point of distribution
>
> For a modern gas turbine power plant the figure is typically in the
> 30-35% range at full power
>
> Diesel engines are typically around 35-45% with spark ignition
> engines 27-40%
It is the upper limit on the gasoline engines that appear strange.
What is the median value for new cars on the road? The 25% figure
is what I have in my mind. The 40% looks like some odd duck
extreme figure. I am looking for "typical".
> the thermodyanmic trap of heat engines.
>
> Not really. You need to produce, store and distribute the H2
> used by the fuel cells and that is typically done by the steam reforming
> of natural gas (a process producing LARGE amounts of CO2) or
> electrloysis.
Obviously the dream is generating the H2 from sunlight when
in fact there is no real industrial way of doing that now.
I discount the hydrogen economy if it is based on the transport
and storage of H2. I find the danger level too high.
Any of the ecological solutions has to avoid releasing more CO2
into the atmosphere to be political correct.
> This turns out to be LESS efficient than using the natural gas
> to drive closed cycle gas turbines.
>> Over all chemical to electrical energy conversions should reach the
>> practical level of 80%.
>
> No Mam. The electrical efficiency of most fuel cells is closer
> to 45% due to losses in fuel reformer, the cell stack, the inverter
> and the auxiliary equipment.
Are you saying that the H2/O2 fuel cell is 45% efficient? You used
the term "most". I thought the number of really operational fuel
cells low. The literature says efficiencies in the 40-70% range and
you chose the low range limit? If you a list with their efficiences
that might prove instructive. My figure of 80% has the caveat
"should reach".
> >> The problem is, of course "the fuel cell", what fuel cell? The hydrogen
>> economy proposition has it own set of problems, I would not like to
>> fool around with stored (in whatever form) hydrogen gas. One proposition
>> is to go over to a methanol economy, using it as the carrier, for which,
>> I understand, there exists now a good fuel cell.
>
> Methanol of course is also an excellent fuel for conventional
> spark ignition engines but you must first produce your methanol
> which has its own problems.
The goal here would be a sustainable non-fossil fuel source, which means
biological right now, like from wood. Industrially methanol is obtained from
methane which is a fossil fuel (we think!). Even now, conversation of H2 in
methanol would be better than direct use of H2, for transport reasons.
Whatever, photosynthesis is just reversed combustion, CO2 + H20 => (CH2=O)x
+ 02 and use of sunlight is the eventual key. It is where fossile fuels came
from and if man is so smart, he should be able to figure out a practical
way of doing the same thing.
Earl
Mar 4th 2004, 2:07 am
#77
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths ForceGermanstoRethinkPassion for Speed
"Earl Evleth" <[email protected]> wrote in message
news:BC6CE9C6.28B1E%[email protected]...
> On 4/03/04 13:19, in article [email protected], "Keith
> Willshaw" <[email protected]> wrote:
> >
> > No Mam. The electrical efficiency of most fuel cells is closer
> > to 45% due to losses in fuel reformer, the cell stack, the inverter
> > and the auxiliary equipment.
> Are you saying that the H2/O2 fuel cell is 45% efficient? You used
> the term "most". I thought the number of really operational fuel
> cells low. The literature says efficiencies in the 40-70% range and
> you chose the low range limit? If you a list with their efficiences
> that might prove instructive. My figure of 80% has the caveat
> "should reach".
I'm saying (or rather the DOE is saying) that when
you look at real world applications where the
fuel stream is natural gas rather than H2 which is
not available as a commercial fuel the efficiencies
including the reformer process needed to extract
the H2 is nearer 45%. If you couple this with a
micro turbine to utilise the reformer heat output
you can reach 60-65%
The only commercial manufacturer of such fuel cells
is United Technologies and they quote 40 percent of
available fuel to electricity compared with 20 percent
conversion for traditional combustion power plants.
http://www.utcfuelcells.com/
If in addition you can re-use the waste heat
output from the turbines you may reach 80% but I'll
wager few utilities will ever reach this, especially in countries
where the peak load is associated with summer A/C use
The problem is that even the simple fuel cell systems
are around 5-7 times the capital cost of similar
cnventional systems making them uneconomic
without considerable tax breaks.
> > >> The problem is, of course "the fuel cell", what fuel cell? The
hydrogen
> >> economy proposition has it own set of problems, I would not like to
> >> fool around with stored (in whatever form) hydrogen gas. One
proposition
> >> is to go over to a methanol economy, using it as the carrier, for
which,
> >> I understand, there exists now a good fuel cell.
> >
> > Methanol of course is also an excellent fuel for conventional
> > spark ignition engines but you must first produce your methanol
> > which has its own problems.
> The goal here would be a sustainable non-fossil fuel source, which means
> biological right now, like from wood. Industrially methanol is obtained
from
> methane which is a fossil fuel (we think!). Even now, conversation of H2
in
> methanol would be better than direct use of H2, for transport reasons.
> Whatever, photosynthesis is just reversed combustion, CO2 + H20 =>
(CH2=O)x
> + 02 and use of sunlight is the eventual key. It is where fossile fuels
came
> from and if man is so smart, he should be able to figure out a practical
> way of doing the same thing.
Do google search on biodiesel but do reacall that the
fossil fuels burnt in 10 years or so were laid down
over a period 1000 times as long and present yields
make it impractical to replace more than a portion of
energy usage.
Keith
news:BC6CE9C6.28B1E%[email protected]...
> On 4/03/04 13:19, in article [email protected], "Keith
> Willshaw" <[email protected]> wrote:
> >
> > No Mam. The electrical efficiency of most fuel cells is closer
> > to 45% due to losses in fuel reformer, the cell stack, the inverter
> > and the auxiliary equipment.
> Are you saying that the H2/O2 fuel cell is 45% efficient? You used
> the term "most". I thought the number of really operational fuel
> cells low. The literature says efficiencies in the 40-70% range and
> you chose the low range limit? If you a list with their efficiences
> that might prove instructive. My figure of 80% has the caveat
> "should reach".
I'm saying (or rather the DOE is saying) that when
you look at real world applications where the
fuel stream is natural gas rather than H2 which is
not available as a commercial fuel the efficiencies
including the reformer process needed to extract
the H2 is nearer 45%. If you couple this with a
micro turbine to utilise the reformer heat output
you can reach 60-65%
The only commercial manufacturer of such fuel cells
is United Technologies and they quote 40 percent of
available fuel to electricity compared with 20 percent
conversion for traditional combustion power plants.
http://www.utcfuelcells.com/
If in addition you can re-use the waste heat
output from the turbines you may reach 80% but I'll
wager few utilities will ever reach this, especially in countries
where the peak load is associated with summer A/C use
The problem is that even the simple fuel cell systems
are around 5-7 times the capital cost of similar
cnventional systems making them uneconomic
without considerable tax breaks.
> > >> The problem is, of course "the fuel cell", what fuel cell? The
hydrogen
> >> economy proposition has it own set of problems, I would not like to
> >> fool around with stored (in whatever form) hydrogen gas. One
proposition
> >> is to go over to a methanol economy, using it as the carrier, for
which,
> >> I understand, there exists now a good fuel cell.
> >
> > Methanol of course is also an excellent fuel for conventional
> > spark ignition engines but you must first produce your methanol
> > which has its own problems.
> The goal here would be a sustainable non-fossil fuel source, which means
> biological right now, like from wood. Industrially methanol is obtained
from
> methane which is a fossil fuel (we think!). Even now, conversation of H2
in
> methanol would be better than direct use of H2, for transport reasons.
> Whatever, photosynthesis is just reversed combustion, CO2 + H20 =>
(CH2=O)x
> + 02 and use of sunlight is the eventual key. It is where fossile fuels
came
> from and if man is so smart, he should be able to figure out a practical
> way of doing the same thing.
Do google search on biodiesel but do reacall that the
fossil fuels burnt in 10 years or so were laid down
over a period 1000 times as long and present yields
make it impractical to replace more than a portion of
energy usage.
Keith
Mar 4th 2004, 2:51 am
#78
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths ForceGermanstoRethinkPassion for Speed
On Thu, 04 Mar 2004 12:19:23 +0000, Keith Willshaw wrote:
>
> "Earl Evleth" <[email protected]> wrote in message
> news:BC6CD467.28B0F%[email protected]...
>> On 4/03/04 10:44, in article [email protected], "Keith
>> Willshaw" <[email protected]> wrote:
>> > The problem with electric motors is generating and storing the
>> > power to drive them. The thermal efficiency of the typical
>> > fossil fuelled power plant is around 30% which is BELOW
>> > that of an efficient 4 stroke engine.
>> First, are you sure of that figure?
>
> Yep
Still, statements like these require so many qualifications that they are
essentially useless.
I suppose if you look at the entire set of thermal plants, and/or include
distribution losses, perhaps you get something like that.
But then, either steam plants or good diesel plants get around 45%. And
heat recovery cycles get better.
And these guys work mostly at full power. While cars when idling have a
zero % efficiency.
>> 1) My memory is that the Carnot efficiency of the auto gasoline engine was
>> about 25%, Diesel higher since they run hotter.
As other folks have mentioned, this is not *Carnot* efficiency. Just the
thermal efficiency. Which is somewhat affected by Carnot efficiency. To
the extent that they cannot be higher than the Carnot efficiency based
upon the adiabatic flame temperature, and that that value has some effect.
> For a modern gas turbine power plant the figure is typically in the
> 30-35% range at full power
A contribution to a low overall average.
> Diesel engines are typically around 35-45% with spark ignition
> engines 27-40%
40% for an SI engine sounds high, but I suppose not impossible. This
figure will, however, correspond to peak efficiency, which represents as
tiny fraction of the "mission profile." I would think the average
efficiency over the life of the engine is probably more like 10-15%, if
you consider traffic and driving patterns. When stopped at a right light,
your efficiency is 0.
> Not really. You need to produce, store and distribute the H2 used by the
> fuel cells and that is typically done by the steam reforming of natural
> gas (a process producing LARGE amounts of CO2) or electrloysis.
>
> This turns out to be LESS efficient than using the natural gas to drive
> closed cycle gas turbines.
OTOH, your fuel cell powered car does not require energy when stopped at
a red light.
>
> "Earl Evleth" <[email protected]> wrote in message
> news:BC6CD467.28B0F%[email protected]...
>> On 4/03/04 10:44, in article [email protected], "Keith
>> Willshaw" <[email protected]> wrote:
>> > The problem with electric motors is generating and storing the
>> > power to drive them. The thermal efficiency of the typical
>> > fossil fuelled power plant is around 30% which is BELOW
>> > that of an efficient 4 stroke engine.
>> First, are you sure of that figure?
>
> Yep
Still, statements like these require so many qualifications that they are
essentially useless.
I suppose if you look at the entire set of thermal plants, and/or include
distribution losses, perhaps you get something like that.
But then, either steam plants or good diesel plants get around 45%. And
heat recovery cycles get better.
And these guys work mostly at full power. While cars when idling have a
zero % efficiency.
>> 1) My memory is that the Carnot efficiency of the auto gasoline engine was
>> about 25%, Diesel higher since they run hotter.
As other folks have mentioned, this is not *Carnot* efficiency. Just the
thermal efficiency. Which is somewhat affected by Carnot efficiency. To
the extent that they cannot be higher than the Carnot efficiency based
upon the adiabatic flame temperature, and that that value has some effect.
> For a modern gas turbine power plant the figure is typically in the
> 30-35% range at full power
A contribution to a low overall average.
> Diesel engines are typically around 35-45% with spark ignition
> engines 27-40%
40% for an SI engine sounds high, but I suppose not impossible. This
figure will, however, correspond to peak efficiency, which represents as
tiny fraction of the "mission profile." I would think the average
efficiency over the life of the engine is probably more like 10-15%, if
you consider traffic and driving patterns. When stopped at a right light,
your efficiency is 0.
> Not really. You need to produce, store and distribute the H2 used by the
> fuel cells and that is typically done by the steam reforming of natural
> gas (a process producing LARGE amounts of CO2) or electrloysis.
>
> This turns out to be LESS efficient than using the natural gas to drive
> closed cycle gas turbines.
OTOH, your fuel cell powered car does not require energy when stopped at
a red light.
Mar 4th 2004, 3:24 am
#79
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths ForceGermanstoRethinkPassion for Speed
"devil" <[email protected]> wrote in message
news
[email protected]...
> On Thu, 04 Mar 2004 12:19:23 +0000, Keith Willshaw wrote:
> >
> > "Earl Evleth" <[email protected]> wrote in message
> > news:BC6CD467.28B0F%[email protected]...
> >> On 4/03/04 10:44, in article [email protected], "Keith
> >> Willshaw" <[email protected]> wrote:
> >>
> >> > The problem with electric motors is generating and storing the
> >> > power to drive them. The thermal efficiency of the typical
> >> > fossil fuelled power plant is around 30% which is BELOW
> >> > that of an efficient 4 stroke engine.
> >>
> >>
> >> First, are you sure of that figure?
> >>
> >
> > Yep
> Still, statements like these require so many qualifications that they are
> essentially useless.
> I suppose if you look at the entire set of thermal plants, and/or include
> distribution losses, perhaps you get something like that.
Not really you just need to look at the heat input in the form of fuel
versus electricity out.
> But then, either steam plants or good diesel plants get around 45%. And
> heat recovery cycles get better.
The BEST steam plants can get to 45% and there are a lot of older
plants out there doing a whole lot worse. Coal fired plants are
a real problem , the soot and clinker deposition knocks efficiencies
right down by the time the boiler is due for overhaul. There are
a hell of lot of old power plants in use around the world that will
struggle to make 30% on a good day.
Consider the Sheldon 1 Station in Nebraska
The existing plant uses 1960's vintage coal fire boilers and has a
nett efficiency of 30.9% . There is a proposal under consderation
to reboiler it with high efficiency fluidised bed furnaces which would
raise the efficiency to 36.2%
> And these guys work mostly at full power. While cars when idling have a
> zero % efficiency.
As does any engine, thats what idling MEANS, note that you cant just turn
off
steam plants , they need to be warmed through before starting which
usually means turbines in power plants are kept turning with some steam
being fed in when on standby. This is a real problem in power generation
where demand has real peaks and troughs
Gas Turbines are horribly expensive at idle when they can easily
use 50% of the fuel they consume at full load
> >> 1) My memory is that the Carnot efficiency of the auto gasoline engine
was
> >> about 25%, Diesel higher since they run hotter.
> As other folks have mentioned, this is not *Carnot* efficiency. Just the
> thermal efficiency. Which is somewhat affected by Carnot efficiency. To
> the extent that they cannot be higher than the Carnot efficiency based
> upon the adiabatic flame temperature, and that that value has some effect.
> > For a modern gas turbine power plant the figure is typically in the
> > 30-35% range at full power
> A contribution to a low overall average.
> > Diesel engines are typically around 35-45% with spark ignition
> > engines 27-40%
> 40% for an SI engine sounds high, but I suppose not impossible. This
> figure will, however, correspond to peak efficiency, which represents as
> tiny fraction of the "mission profile." I would think the average
> efficiency over the life of the engine is probably more like 10-15%, if
> you consider traffic and driving patterns. When stopped at a right light,
> your efficiency is 0.
Naturally since work done is also zero
> > Not really. You need to produce, store and distribute the H2 used by the
> > fuel cells and that is typically done by the steam reforming of natural
> > gas (a process producing LARGE amounts of CO2) or electrloysis.
> >
> > This turns out to be LESS efficient than using the natural gas to drive
> > closed cycle gas turbines.
> OTOH, your fuel cell powered car does not require energy when stopped at
> a red light.
Sure but if you are using a hybrid vehicle with a small ic engine topping
off a battery charge thats true as well. Fuel cells are not currently
available in commercially produced vehicles as I recall. Hybrid
cars are starting to come to the market.
Keith
news
[email protected]...> On Thu, 04 Mar 2004 12:19:23 +0000, Keith Willshaw wrote:
> >
> > "Earl Evleth" <[email protected]> wrote in message
> > news:BC6CD467.28B0F%[email protected]...
> >> On 4/03/04 10:44, in article [email protected], "Keith
> >> Willshaw" <[email protected]> wrote:
> >>
> >> > The problem with electric motors is generating and storing the
> >> > power to drive them. The thermal efficiency of the typical
> >> > fossil fuelled power plant is around 30% which is BELOW
> >> > that of an efficient 4 stroke engine.
> >>
> >>
> >> First, are you sure of that figure?
> >>
> >
> > Yep
> Still, statements like these require so many qualifications that they are
> essentially useless.
> I suppose if you look at the entire set of thermal plants, and/or include
> distribution losses, perhaps you get something like that.
Not really you just need to look at the heat input in the form of fuel
versus electricity out.
> But then, either steam plants or good diesel plants get around 45%. And
> heat recovery cycles get better.
The BEST steam plants can get to 45% and there are a lot of older
plants out there doing a whole lot worse. Coal fired plants are
a real problem , the soot and clinker deposition knocks efficiencies
right down by the time the boiler is due for overhaul. There are
a hell of lot of old power plants in use around the world that will
struggle to make 30% on a good day.
Consider the Sheldon 1 Station in Nebraska
The existing plant uses 1960's vintage coal fire boilers and has a
nett efficiency of 30.9% . There is a proposal under consderation
to reboiler it with high efficiency fluidised bed furnaces which would
raise the efficiency to 36.2%
> And these guys work mostly at full power. While cars when idling have a
> zero % efficiency.
As does any engine, thats what idling MEANS, note that you cant just turn
off
steam plants , they need to be warmed through before starting which
usually means turbines in power plants are kept turning with some steam
being fed in when on standby. This is a real problem in power generation
where demand has real peaks and troughs
Gas Turbines are horribly expensive at idle when they can easily
use 50% of the fuel they consume at full load
> >> 1) My memory is that the Carnot efficiency of the auto gasoline engine
was
> >> about 25%, Diesel higher since they run hotter.
> As other folks have mentioned, this is not *Carnot* efficiency. Just the
> thermal efficiency. Which is somewhat affected by Carnot efficiency. To
> the extent that they cannot be higher than the Carnot efficiency based
> upon the adiabatic flame temperature, and that that value has some effect.
> > For a modern gas turbine power plant the figure is typically in the
> > 30-35% range at full power
> A contribution to a low overall average.
> > Diesel engines are typically around 35-45% with spark ignition
> > engines 27-40%
> 40% for an SI engine sounds high, but I suppose not impossible. This
> figure will, however, correspond to peak efficiency, which represents as
> tiny fraction of the "mission profile." I would think the average
> efficiency over the life of the engine is probably more like 10-15%, if
> you consider traffic and driving patterns. When stopped at a right light,
> your efficiency is 0.
Naturally since work done is also zero
> > Not really. You need to produce, store and distribute the H2 used by the
> > fuel cells and that is typically done by the steam reforming of natural
> > gas (a process producing LARGE amounts of CO2) or electrloysis.
> >
> > This turns out to be LESS efficient than using the natural gas to drive
> > closed cycle gas turbines.
> OTOH, your fuel cell powered car does not require energy when stopped at
> a red light.
Sure but if you are using a hybrid vehicle with a small ic engine topping
off a battery charge thats true as well. Fuel cells are not currently
available in commercially produced vehicles as I recall. Hybrid
cars are starting to come to the market.
Keith
Mar 4th 2004, 3:31 am
#80
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths ForceGermanstoRethinkPassion
On 4/03/04 16:07, in article [email protected], "Keith
Willshaw" <[email protected]> wrote:
> "Earl Evleth" <[email protected]> wrote in message
> news:BC6CE9C6.28B1E%[email protected]...
>> On 4/03/04 13:19, in article [email protected], "Keith
>> Willshaw" <[email protected]> wrote:
>
> I'm saying (or rather the DOE is saying)
"ouch", that is now ran by the Bush administration isn't it?
> that when you look at real world applications where the
> fuel stream is natural gas rather than H2 which is
> not available as a commercial fuel the efficiencies
> including the reformer process needed to extract
> the H2 is nearer 45%. If you couple this with a
> micro turbine to utilise the reformer heat output
> you can reach 60-65%
Yes I have seen these combinations and know those figures.
> The only commercial manufacturer of such fuel cells
> is United Technologies and they quote 40 percent of
> available fuel to electricity compared with 20 percent
> conversion for traditional combustion power plants.
I have seen this, the Wall Street Journal covers this
kind of thing fairly regularly. I also receive my professional
magazine, Chemical and Engineering News which updates me
on technology.
But the first fuel cell applications I know of where on the
Apollo missions, these were hydrogen-oxygen fuel cells which
I think are the "best" that technology has produced efficiency wise
not the most practical nor the cheapest. It still represents a target
for other systems, which I why I site that higher figure.
> Do google search on biodiesel but do recall that the
> fossil fuels burnt in 10 years or so were laid down
> over a period 1000 times as long and present yields
> make it impractical to replace more than a portion of
> energy usage.
That is true. But biomass recycling is possible.
The fossil fuels have the problem of CO2 release into the
atmosphere and that is the critical problem in the near
future, unless you are into global warming denial.
If that were not a problem we would have fossil fuels
available for the indefinite future (coal, oil sands
oil shale, and methane hydrates).
But our research in other areas is not intensive enough.
For instance, the photosynthetic efficiency of cane sugar
production is under 1%, doubling that does not seem out of line.
The material sciences could come up with progressively
more efficient ways of making H2 from photocells.
Earl
Willshaw" <[email protected]> wrote:
> "Earl Evleth" <[email protected]> wrote in message
> news:BC6CE9C6.28B1E%[email protected]...
>> On 4/03/04 13:19, in article [email protected], "Keith
>> Willshaw" <[email protected]> wrote:
>
> I'm saying (or rather the DOE is saying)
"ouch", that is now ran by the Bush administration isn't it?
> that when you look at real world applications where the
> fuel stream is natural gas rather than H2 which is
> not available as a commercial fuel the efficiencies
> including the reformer process needed to extract
> the H2 is nearer 45%. If you couple this with a
> micro turbine to utilise the reformer heat output
> you can reach 60-65%
Yes I have seen these combinations and know those figures.
> The only commercial manufacturer of such fuel cells
> is United Technologies and they quote 40 percent of
> available fuel to electricity compared with 20 percent
> conversion for traditional combustion power plants.
I have seen this, the Wall Street Journal covers this
kind of thing fairly regularly. I also receive my professional
magazine, Chemical and Engineering News which updates me
on technology.
But the first fuel cell applications I know of where on the
Apollo missions, these were hydrogen-oxygen fuel cells which
I think are the "best" that technology has produced efficiency wise
not the most practical nor the cheapest. It still represents a target
for other systems, which I why I site that higher figure.
> Do google search on biodiesel but do recall that the
> fossil fuels burnt in 10 years or so were laid down
> over a period 1000 times as long and present yields
> make it impractical to replace more than a portion of
> energy usage.
That is true. But biomass recycling is possible.
The fossil fuels have the problem of CO2 release into the
atmosphere and that is the critical problem in the near
future, unless you are into global warming denial.
If that were not a problem we would have fossil fuels
available for the indefinite future (coal, oil sands
oil shale, and methane hydrates).
But our research in other areas is not intensive enough.
For instance, the photosynthetic efficiency of cane sugar
production is under 1%, doubling that does not seem out of line.
The material sciences could come up with progressively
more efficient ways of making H2 from photocells.
Earl
Mar 4th 2004, 3:47 am
#81
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths ForceGermanstoRethinkPassion for Speed
On Thu, 04 Mar 2004 16:24:33 +0000, Keith Willshaw wrote:
>
> "devil" <[email protected]> wrote in message
> news[email protected]...
>> On Thu, 04 Mar 2004 12:19:23 +0000, Keith Willshaw wrote:
>> >
>> > "Earl Evleth" <[email protected]> wrote in message
>> > news:BC6CD467.28B0F%[email protected]...
>> >> On 4/03/04 10:44, in article [email protected], "Keith
>> >> Willshaw" <[email protected]> wrote:
>> >>
>> >> > The problem with electric motors is generating and storing the
>> >> > power to drive them. The thermal efficiency of the typical
>> >> > fossil fuelled power plant is around 30% which is BELOW
>> >> > that of an efficient 4 stroke engine.
>> >>
>> >>
>> >> First, are you sure of that figure?
>> >>
>> >
>> > Yep
>> Still, statements like these require so many qualifications that they are
>> essentially useless.
>> I suppose if you look at the entire set of thermal plants, and/or include
>> distribution losses, perhaps you get something like that.
>
> Not really you just need to look at the heat input in the form of fuel
> versus electricity out.
Obviously. My point was that there is a wide range of situations.
>> And these guys work mostly at full power. While cars when idling have a
>> zero % efficiency.
>
> As does any engine, thats what idling MEANS, note that you cant just turn
> off
> steam plants , they need to be warmed through before starting which
> usually means turbines in power plants are kept turning with some steam
> being fed in when on standby. This is a real problem in power generation
> where demand has real peaks and troughs
>
> Gas Turbines are horribly expensive at idle when they can easily
> use 50% of the fuel they consume at full load
Point remains that the way you operate these is nothing like your car.
Power plants do not normally spend a significant part of their life far
away from their optimal operating point.
>> 40% for an SI engine sounds high, but I suppose not impossible. This
>> figure will, however, correspond to peak efficiency, which represents as
>> tiny fraction of the "mission profile." I would think the average
>> efficiency over the life of the engine is probably more like 10-15%, if
>> you consider traffic and driving patterns. When stopped at a right light,
>> your efficiency is 0.
>
> Naturally since work done is also zero
Point remains that this is a significant contribution to your car fuel
economy. Peak efficiency is not terribly relvant when dealing with cars.
It is when dealing with power plants.
>> OTOH, your fuel cell powered car does not require energy when stopped at
>> a red light.
>
> Sure but if you are using a hybrid vehicle with a small ic engine topping
> off a battery charge thats true as well. Fuel cells are not currently
> available in commercially produced vehicles as I recall. Hybrid
> cars are starting to come to the market.
Sure. Hybrid cars amke sense. But a reliable and efficient fuel cell may
ultimately make more sense.
In your hybrid vehicle, you need batteries and an electric drive. Just
like with fuel cells, which are at the end of the day a close cousin of
your battery.
However, in the hybrid car, you need to add your engine, alternator,
rectifier etc. Which are not needed in your fuel cell car.
You'll argue that you still need to produce hydrogen etc. But producing
it in a large scale stationary plant should be a better situation than
having your prime thermal engine with you as part of your payload.
Anyway, the jury is still out on this one.
>
> "devil" <[email protected]> wrote in message
> news
[email protected]...>> On Thu, 04 Mar 2004 12:19:23 +0000, Keith Willshaw wrote:
>> >
>> > "Earl Evleth" <[email protected]> wrote in message
>> > news:BC6CD467.28B0F%[email protected]...
>> >> On 4/03/04 10:44, in article [email protected], "Keith
>> >> Willshaw" <[email protected]> wrote:
>> >>
>> >> > The problem with electric motors is generating and storing the
>> >> > power to drive them. The thermal efficiency of the typical
>> >> > fossil fuelled power plant is around 30% which is BELOW
>> >> > that of an efficient 4 stroke engine.
>> >>
>> >>
>> >> First, are you sure of that figure?
>> >>
>> >
>> > Yep
>> Still, statements like these require so many qualifications that they are
>> essentially useless.
>> I suppose if you look at the entire set of thermal plants, and/or include
>> distribution losses, perhaps you get something like that.
>
> Not really you just need to look at the heat input in the form of fuel
> versus electricity out.
Obviously. My point was that there is a wide range of situations.
>> And these guys work mostly at full power. While cars when idling have a
>> zero % efficiency.
>
> As does any engine, thats what idling MEANS, note that you cant just turn
> off
> steam plants , they need to be warmed through before starting which
> usually means turbines in power plants are kept turning with some steam
> being fed in when on standby. This is a real problem in power generation
> where demand has real peaks and troughs
>
> Gas Turbines are horribly expensive at idle when they can easily
> use 50% of the fuel they consume at full load
Point remains that the way you operate these is nothing like your car.
Power plants do not normally spend a significant part of their life far
away from their optimal operating point.
>> 40% for an SI engine sounds high, but I suppose not impossible. This
>> figure will, however, correspond to peak efficiency, which represents as
>> tiny fraction of the "mission profile." I would think the average
>> efficiency over the life of the engine is probably more like 10-15%, if
>> you consider traffic and driving patterns. When stopped at a right light,
>> your efficiency is 0.
>
> Naturally since work done is also zero
Point remains that this is a significant contribution to your car fuel
economy. Peak efficiency is not terribly relvant when dealing with cars.
It is when dealing with power plants.
>> OTOH, your fuel cell powered car does not require energy when stopped at
>> a red light.
>
> Sure but if you are using a hybrid vehicle with a small ic engine topping
> off a battery charge thats true as well. Fuel cells are not currently
> available in commercially produced vehicles as I recall. Hybrid
> cars are starting to come to the market.
Sure. Hybrid cars amke sense. But a reliable and efficient fuel cell may
ultimately make more sense.
In your hybrid vehicle, you need batteries and an electric drive. Just
like with fuel cells, which are at the end of the day a close cousin of
your battery.
However, in the hybrid car, you need to add your engine, alternator,
rectifier etc. Which are not needed in your fuel cell car.
You'll argue that you still need to produce hydrogen etc. But producing
it in a large scale stationary plant should be a better situation than
having your prime thermal engine with you as part of your payload.
Anyway, the jury is still out on this one.
Mar 4th 2004, 7:28 pm
#82
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths ForceGermanstoRethinkPassion
On 4/03/04 16:51, in article [email protected],
"devil" <[email protected]> wrote:
>
> OTOH, your fuel cell powered car does not require energy when stopped at
> a red light.
Or traffic jams.
An electric motor driven system, if it has also a storage cell available,
could recover some energy on breaking. Whether this is cost effective
is the problem.
I stressed the Carnot cycle angle because this does represent the
thermodynamic limit for heat => work conversion.
In teaching thermodyanmics and electrochemical cells, I found it useful
also to develop the idea of entropy driven reactions because there
are some in biochemical systems. There are actually some reactions
which have zero energy change but proceed spontaneously because
the system is going to a more disordered state. Students of
the subject have to master the difference between enthalpy
and free energy (usable energy). One could run a vehicle on
compressed air or even liquid nitrogen (and steal heat from
the environment) if one wanted. However, any heat exchanger
I can imagine would ice up (heat pumps can do this too).
In the energy panic days of the 70s, kinetic energy storage with flywheels
was proposed and I think the Swiss had some short distance urban rail
systems running on these. The only one I have seen personally was
in the form of a children's toy car.
Earl
"devil" <[email protected]> wrote:
>
> OTOH, your fuel cell powered car does not require energy when stopped at
> a red light.
Or traffic jams.
An electric motor driven system, if it has also a storage cell available,
could recover some energy on breaking. Whether this is cost effective
is the problem.
I stressed the Carnot cycle angle because this does represent the
thermodynamic limit for heat => work conversion.
In teaching thermodyanmics and electrochemical cells, I found it useful
also to develop the idea of entropy driven reactions because there
are some in biochemical systems. There are actually some reactions
which have zero energy change but proceed spontaneously because
the system is going to a more disordered state. Students of
the subject have to master the difference between enthalpy
and free energy (usable energy). One could run a vehicle on
compressed air or even liquid nitrogen (and steal heat from
the environment) if one wanted. However, any heat exchanger
I can imagine would ice up (heat pumps can do this too).
In the energy panic days of the 70s, kinetic energy storage with flywheels
was proposed and I think the Swiss had some short distance urban rail
systems running on these. The only one I have seen personally was
in the form of a children's toy car.
Earl
Mar 4th 2004, 8:34 pm
#83
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths ForceGermanstoRethinkPassion for Speed
"Earl Evleth" <[email protected]> wrote in message
news:BC6DF8C3.28C4F%[email protected]...
> On 4/03/04 16:51, in article [email protected],
> "devil" <[email protected]> wrote:
> In the energy panic days of the 70s, kinetic energy storage with flywheels
> was proposed and I think the Swiss had some short distance urban rail
> systems running on these. The only one I have seen personally was
> in the form of a children's toy car.
The problem with flywheels is that they can do immense damage
if they break loose. Their are also some issues with precession
forces in a mobile application. The WW1 Rotary engines had an
arrangement where the crankshaft was fixed and the engineblock
rotated, a side effect was that engine acted as a large gyroscope
and precession made handling rather challenging.
Keith
news:BC6DF8C3.28C4F%[email protected]...
> On 4/03/04 16:51, in article [email protected],
> "devil" <[email protected]> wrote:
> In the energy panic days of the 70s, kinetic energy storage with flywheels
> was proposed and I think the Swiss had some short distance urban rail
> systems running on these. The only one I have seen personally was
> in the form of a children's toy car.
The problem with flywheels is that they can do immense damage
if they break loose. Their are also some issues with precession
forces in a mobile application. The WW1 Rotary engines had an
arrangement where the crankshaft was fixed and the engineblock
rotated, a side effect was that engine acted as a large gyroscope
and precession made handling rather challenging.
Keith
Mar 5th 2004, 3:30 am
#84
Guest
Posts: n/a
Flywheel energy storage
Earl Evleth wrote:
> On 4/03/04 16:51, in article [email protected],
snip
> In the energy panic days of the 70s, kinetic energy storage with flywheels
> was proposed and I think the Swiss had some short distance urban rail
> systems running on these. The only one I have seen personally was
> in the form of a children's toy car.
> Earl
I have seen one massive kinetic energy storage system. It was a part of
the power protection system for the US Steel Corp. computer center in
Pittsburgh in the late 60s. It was intended to bridge the gap between
failure of the power net and the diesel generators. The thing was a
rotating granite cylinder that I remember as about a 30 to 50 cm in
thickness and 2m or so in diameter rotating quite rapidly.
I have no idea how often it was used but it was there spinning away.
FFM
> On 4/03/04 16:51, in article [email protected],
snip
> In the energy panic days of the 70s, kinetic energy storage with flywheels
> was proposed and I think the Swiss had some short distance urban rail
> systems running on these. The only one I have seen personally was
> in the form of a children's toy car.
> Earl
I have seen one massive kinetic energy storage system. It was a part of
the power protection system for the US Steel Corp. computer center in
Pittsburgh in the late 60s. It was intended to bridge the gap between
failure of the power net and the diesel generators. The thing was a
rotating granite cylinder that I remember as about a 30 to 50 cm in
thickness and 2m or so in diameter rotating quite rapidly.
I have no idea how often it was used but it was there spinning away.
FFM
Mar 7th 2004, 12:22 pm
#85
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths Force Germans to Rethink Passion for Speed
Are you guys actually serious; suggesting that traffic laws impugn
personal rights...??? HA!
How about the notion that traffic laws *protect* all from those who are
irresponsible drivers who will not act sensible on the road...
Eventually they do get their *privilege* removed through law
enforcement; this is good for all.
But feel free to be a contrary as you dare anyway libertines...<g> Just
don't impinge the rights (to live) of anyone else by being a self
centered fool on the road. Your driving 'rights' end far short of that.
Tim K
"Jesper Lauridsen" <[email protected]> wrote in message
news:[email protected]...
> On Sun, 29 Feb 2004 12:50:41 -0000, "Keith Willshaw"
<[email protected]> wrote:
> >
> >"Tim Kroesen" <[email protected]> wrote in message
> >news:[email protected]...
> >> Why would carrying any argument to the nth degree be logical for
every
> >> subject and instance?
> >>
> >
> >It isnt , but it shows that a statement that safety is the only thing
that
> >matters is patently false. Policy in this area is a compromise
between
> >safety, cost and convenience.
> Yes, the argument that "X deaths are X too many" is crap, as the only
way to
> reach zero is to force everyone too stay home. Unless one is prepared
to go
> that far, one has to accept that accidents will happen and that it's
possible
> to go too far in the pursuit of safety.
personal rights...??? HA!
How about the notion that traffic laws *protect* all from those who are
irresponsible drivers who will not act sensible on the road...
Eventually they do get their *privilege* removed through law
enforcement; this is good for all.
But feel free to be a contrary as you dare anyway libertines...<g> Just
don't impinge the rights (to live) of anyone else by being a self
centered fool on the road. Your driving 'rights' end far short of that.
Tim K
"Jesper Lauridsen" <[email protected]> wrote in message
news:[email protected]...
> On Sun, 29 Feb 2004 12:50:41 -0000, "Keith Willshaw"
<[email protected]> wrote:
> >
> >"Tim Kroesen" <[email protected]> wrote in message
> >news:[email protected]...
> >> Why would carrying any argument to the nth degree be logical for
every
> >> subject and instance?
> >>
> >
> >It isnt , but it shows that a statement that safety is the only thing
that
> >matters is patently false. Policy in this area is a compromise
between
> >safety, cost and convenience.
> Yes, the argument that "X deaths are X too many" is crap, as the only
way to
> reach zero is to force everyone too stay home. Unless one is prepared
to go
> that far, one has to accept that accidents will happen and that it's
possible
> to go too far in the pursuit of safety.
Mar 7th 2004, 8:32 pm
#86
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths Force Germans to Rethink Passion for Speed
On Mon, 8 Mar 2004 09:35:57 -0000, Keith Willshaw wrote:
>> Eventually they do get their *privilege* removed through law
>> enforcement; this is good for all.
>
> Indeed but that is usually AFTER the event.
Innocent until proven guilty ?
--
Tim.
If the human brain were simple enough that we could understand it, we would
be so simple that we couldn't.
>> Eventually they do get their *privilege* removed through law
>> enforcement; this is good for all.
>
> Indeed but that is usually AFTER the event.
Innocent until proven guilty ?
--
Tim.
If the human brain were simple enough that we could understand it, we would
be so simple that we couldn't.
Mar 7th 2004, 8:35 pm
#87
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths Force Germans to Rethink Passion for Speed
"Tim Kroesen" <[email protected]> wrote in message
news:[email protected]...
> Are you guys actually serious; suggesting that traffic laws impugn
> personal rights...??? HA!
Of course they do as do all laws by definition, the debate is about
how justified they are. Neither of use argued that the current
level of legislation was too high as I recall
> How about the notion that traffic laws *protect* all from those who are
> irresponsible drivers who will not act sensible on the road...
In fact they dont protect *all*. No law ever passed has managed
to do that. The best that can be managed is to regulate most
drivers, there have always been and will always be lawbreakers.
> Eventually they do get their *privilege* removed through law
> enforcement; this is good for all.
Indeed but that is usually AFTER the event.
> But feel free to be a contrary as you dare anyway libertines...<g> Just
> don't impinge the rights (to live) of anyone else by being a self
> centered fool on the road. Your driving 'rights' end far short of that.
Nice homily but its harly relevant to the proposition that driving
restrictions are a compromise between safety and convenience.
That principle was firmly established when they did away with
the requirement for motor vehicles to be preceded by a man
on foot waving a red flag.
Keith
news:[email protected]...
> Are you guys actually serious; suggesting that traffic laws impugn
> personal rights...??? HA!
Of course they do as do all laws by definition, the debate is about
how justified they are. Neither of use argued that the current
level of legislation was too high as I recall
> How about the notion that traffic laws *protect* all from those who are
> irresponsible drivers who will not act sensible on the road...
In fact they dont protect *all*. No law ever passed has managed
to do that. The best that can be managed is to regulate most
drivers, there have always been and will always be lawbreakers.
> Eventually they do get their *privilege* removed through law
> enforcement; this is good for all.
Indeed but that is usually AFTER the event.
> But feel free to be a contrary as you dare anyway libertines...<g> Just
> don't impinge the rights (to live) of anyone else by being a self
> centered fool on the road. Your driving 'rights' end far short of that.
Nice homily but its harly relevant to the proposition that driving
restrictions are a compromise between safety and convenience.
That principle was firmly established when they did away with
the requirement for motor vehicles to be preceded by a man
on foot waving a red flag.
Keith
Mar 7th 2004, 9:27 pm
#88
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths Force Germans to Rethink Passion for Speed
"Tim Challenger" <"timothy(dot)challenger(at)apk(dot)at"> wrote in message
news:[email protected]...
> On Mon, 8 Mar 2004 09:35:57 -0000, Keith Willshaw wrote:
> >> Eventually they do get their *privilege* removed through law
> >> enforcement; this is good for all.
> >>
> >
> > Indeed but that is usually AFTER the event.
> Innocent until proven guilty ?
Quite correct and thats the way it has to be.
Keith
news:[email protected]...
> On Mon, 8 Mar 2004 09:35:57 -0000, Keith Willshaw wrote:
> >> Eventually they do get their *privilege* removed through law
> >> enforcement; this is good for all.
> >>
> >
> > Indeed but that is usually AFTER the event.
> Innocent until proven guilty ?
Quite correct and thats the way it has to be.
Keith
Mar 11th 2004, 7:15 pm
#89
Guest
Posts: n/a
Re: Washington Post: Autobahn Deaths ForceGermanstoRethinkPassion for Speed
On Fri, 5 Mar 2004 09:34:00 -0000, Keith Willshaw wrote:
> "Earl Evleth" <[email protected]> wrote in message
> news:BC6DF8C3.28C4F%[email protected]...
>> On 4/03/04 16:51, in article [email protected],
>> "devil" <[email protected]> wrote:
>
>> In the energy panic days of the 70s, kinetic energy storage with flywheels
>> was proposed and I think the Swiss had some short distance urban rail
>> systems running on these. The only one I have seen personally was
>> in the form of a children's toy car.
>
> The problem with flywheels is that they can do immense damage
> if they break loose. Their are also some issues with precession
> forces in a mobile application. The WW1 Rotary engines had an
> arrangement where the crankshaft was fixed and the engineblock
> rotated, a side effect was that engine acted as a large gyroscope
> and precession made handling rather challenging.
>
> Keith
Ever ridden a shaft-driven motorbike ?
Espercially the older ones, accelleration and braking on bends is, er,
"disconcerting".
--
Tim.
If the human brain were simple enough that we could understand it, we would
be so simple that we couldn't.
> "Earl Evleth" <[email protected]> wrote in message
> news:BC6DF8C3.28C4F%[email protected]...
>> On 4/03/04 16:51, in article [email protected],
>> "devil" <[email protected]> wrote:
>
>> In the energy panic days of the 70s, kinetic energy storage with flywheels
>> was proposed and I think the Swiss had some short distance urban rail
>> systems running on these. The only one I have seen personally was
>> in the form of a children's toy car.
>
> The problem with flywheels is that they can do immense damage
> if they break loose. Their are also some issues with precession
> forces in a mobile application. The WW1 Rotary engines had an
> arrangement where the crankshaft was fixed and the engineblock
> rotated, a side effect was that engine acted as a large gyroscope
> and precession made handling rather challenging.
>
> Keith
Ever ridden a shaft-driven motorbike ?
Espercially the older ones, accelleration and braking on bends is, er,
"disconcerting".
--
Tim.
If the human brain were simple enough that we could understand it, we would
be so simple that we couldn't.
