SIXTY MINUTES: Bloom Box, Projected As Cost Effective Fuel Cell
in [Basics]
|
Prev: Be ready to be killed, or take action to stop the global suicide. Scandal at CERN.
Next: OPERATIONS AND SUPPLY MANAGEMENT 12-E JACOBS Test Bank and solution manual
From: Bret Cahill on 24 Feb 2010 00:18 > Yes they have great power density because they operate at very > high temperatures (typically above 500C). Not sure what this means but it fits into one admittedly half baked theory on thermo: There is no fundamental difference between fuel cells and heat engines. Carnot and material property limits on both converge to the same sorry prime mover. > Because of high temperature > they have long warm-up time, therefore not very suitable for use > in cars etc, and not even for emergency generators, but rather for > constant load generators. They would be really great for longer range / lower speed cruise missiles. It's not like Iran could build a good 300 kW gas turbine. > Why are they not widespread despite very good efficiency? > 1) Because they are too expensive to make (as the bloom box also > clearly is with > 800 000$ price tag). Now, he has a pipe-dream that price can be > reduced by > order of 266 to 3000 in 2 years. > The entire industry working on the subject during last 50 years > were not able to reduce the cost, but this dude will just do it in 2 > years. > How? He does not say. _60 Minutes_ doesn't know how to ask the right questions. > 2) They degrade quite quickly. There is catalyst poisoning, > decomposition > of solid electrolyte and other issues. So your very expensive toy does > not last > long enough to pay for itself through higher efficiency. > Will SOFC be used more in the future? Quite possible. Lots of people > are working on their improvement. Too bad that con artists are trying > to > take all the credit and present this product of widespread R&D efforts > and thousands > of papers published on the subject every year as their "invention". > > Regards, > Yevgen- Check out what they are paying at the _Wall Street Journal_. It's 100% certain they are short a few science writers. Bret Cahill
From: pamela on 24 Feb 2010 18:53 Bret Cahill wrote: > Not sure what this means but it fits into one admittedly half baked > theory on thermo: > > There is no fundamental difference between fuel cells and heat > engines. > > Carnot and material property limits on both converge to the same sorry > prime mover. > > Bret Cahill > > > Ignoramus in Thermodynamics. The Carnot cycle limitations are entropy driven... the fundamental irreversible nature of heat dissipation. Fuel cells are basically a chemical reaction with a conducting loop for charges thrown in. More like a battery (with mass exchange) than a heat engine. Slog through "Entropy Analysius" by Norman C Craig or some of the newer more modern treatments of Thermodynamics (using basic quantum concepts). The behavior of materials at high temperatures are thermally activated processes of several types.
From: Bret Cahill on 25 Feb 2010 00:26 > > Not sure what this means but it fits into one admittedly half baked > > theory on thermo: > > > There is no fundamental difference between fuel cells and heat > > engines. > > > Carnot and material property limits on both converge to the same sorry > > prime mover. > > > Bret Cahill > > Ignoramus in Thermodynamics. > > The Carnot cycle limitations are entropy driven... Some of the limitations on fuel cells also result from the 2nd Law. There's no controversy about that. The question here is could both start to become indistinguishable from each other in cost, performance and even design? Say, for example, that a fuel cell - heat engine hybrid only had a rotating field for the output -- no solid moving parts. All you had to add was a rotor similar to those in electric motors for mechanical work. In other words, say part or all of the electric motor somehow got absorbed into the rest of the system. Would you call that a heat engine or a fuel cell? Bret Cahill
From: John Larkin on 25 Feb 2010 10:04 On Wed, 24 Feb 2010 21:26:00 -0800 (PST), Bret Cahill <BretCahill(a)peoplepc.com> wrote: >> > Not sure what this means but it fits into one admittedly half baked >> > theory on thermo: >> >> > There is no fundamental difference between fuel cells and heat >> > engines. >> >> > Carnot and material property limits on both converge to the same sorry >> > prime mover. >> >> > Bret Cahill >> >> Ignoramus in Thermodynamics. >> >> The Carnot cycle limitations are entropy driven... > >Some of the limitations on fuel cells also result from the 2nd Law. >There's no controversy about that. > >The question here is could both start to become indistinguishable from >each other in cost, performance and even design? > >Say, for example, that a fuel cell - heat engine hybrid only had a >rotating field for the output -- no solid moving parts. All you had >to add was a rotor similar to those in electric motors for mechanical >work. > >In other words, say part or all of the electric motor somehow got >absorbed into the rest of the system. > >Would you call that a heat engine or a fuel cell? > A fuel cell doesn't use heat as a power transfer mechanism, so it's not a heat engine. It's a battery with replentished chemistry; as such, it can have much higher efficiency than a heat engine. Read this: http://en.wikipedia.org/wiki/Fuel_cell#Efficiency John
From: Bret Cahill on 25 Feb 2010 12:02
> >> > Not sure what this means but it fits into one admittedly half baked > >> > theory on thermo: > >> > There is no fundamental difference between fuel cells and heat > >> > engines. > >> > Carnot and material property limits on both converge to the same sorry > >> > prime mover. > >> > Bret Cahill > >> Ignoramus in Thermodynamics. > >> The Carnot cycle limitations are entropy driven... > > >Some of the limitations on fuel cells also result from the 2nd Law. > >There's no controversy about that. > > >The question here is could both start to become indistinguishable from > >each other in cost, performance and even design? > > >Say, for example, that a fuel cell - heat engine hybrid only had a > >rotating field for the output -- no solid moving parts. All you had > >to add was a rotor similar to those in electric motors for mechanical > >work. > > >In other words, say part or all of the electric motor somehow got > >absorbed into the rest of the system. > > >Would you call that a heat engine or a fuel cell? > > A fuel cell doesn't use heat as a power transfer mechanism, so it's > not a heat engine. Going from fuel to mechanical work heat engines have the additional intermediate step of the addition of heat while fuel cells have the additional intermediate step of an electric motor. It looks like the heat step is more lossy than the electric motor. > It's a battery with replentished chemistry; as > such, it can have much higher efficiency than a heat engine. > > Read this: > > http://en.wikipedia.org/wiki/Fuel_cell#Efficiency We need more comparisons. Some fuel cells use superchargers and for the same reason as reciprocating engines. Bret Cahill |