Generalizing Carnot To Include Fuel Cells
in [Math]
|
Prev: THE MYSTERY OF THE CARROT. OH PARSNIP, WHEREFORE ART THOU?
Next: limit((sum(exp((-1)^k*(Sum(ln(k0-1)/(-1)^k0, k0 = 2 .. k))), k= 2 .. n))/s
From: Bret Cahill on 26 Feb 2010 22:27 > > Carnot is almost two centuries old and only covers heat engines. > > > With the increasing interest in fuel cells it would be nice to have > > something that covers fuel cells as well as heat engines. > > > The similarities in processes as well as results between low pressure > > ratio highly recuperated gas turbines and fuel cells suggests that > > this may be possible: > > > LPR Gas Turbine: theoretical efficiency over 80% > > > Fuel cell: theoretical efficiency over 80% > > > LPRGT: even higher efficiency with ceramics that rapidly degrade > > > FC: even higher efficiency with materials that rapidly degrade > > > LPRGT: heat transfer > > > FC: mass transfer > > > LPRGT: big expensive heat exchanger area for heat transfer > > > FC: expensive contact area for mass transfer > > Do you have a point It's a request: We need something more powerful than Carnot to eliminate fuel-to- mechanical energy devices that will never work or never work as hoped. Bret Cahill
From: jmfbahciv on 27 Feb 2010 08:22 pamela wrote: > J. Clarke wrote: >> On 2/26/2010 10:36 AM, Bret Cahill wrote: >>> Carnot is almost two centuries old and only covers heat engines. >>> >>> With the increasing interest in fuel cells it would be nice to have >>> something that covers fuel cells as well as heat engines. >>> >>> The similarities in processes as well as results between low pressure >>> ratio highly recuperated gas turbines and fuel cells suggests that >>> this may be possible: >>> >>> LPR Gas Turbine: theoretical efficiency over 80% >>> >>> Fuel cell: theoretical efficiency over 80% >>> >>> LPRGT: even higher efficiency with ceramics that rapidly degrade >>> >>> FC: even higher efficiency with materials that rapidly degrade >>> >>> LPRGT: heat transfer >>> >>> FC: mass transfer >>> >>> LPRGT: big expensive heat exchanger area for heat transfer >>> >>> FC: expensive contact area for mass transfer >> >> Do you have a point or are you just rambling? > > > He's trying to "make new science" because he is having trouble with "old > science" because it doesn't say what he wants it to say. I don't understand this attitude. Ignoring reality is boring; nature is full of surprises. /BAH
From: Bret Cahill on 27 Feb 2010 11:27 > > > Carnot is almost two centuries old and only covers heat engines. > > > > With the increasing interest in fuel cells it would be nice to have > > > something that covers fuel cells as well as heat engines. > > > > The similarities in processes as well as results between low pressure > > > ratio highly recuperated gas turbines and fuel cells suggests that > > > this may be possible: > > > > LPR Gas Turbine: theoretical efficiency over 80% > > > > Fuel cell: theoretical efficiency over 80% > > > > LPRGT: even higher efficiency with ceramics that rapidly degrade > > > > FC: even higher efficiency with materials that rapidly degrade > > > > LPRGT: heat transfer > > > > FC: mass transfer > > > > LPRGT: big expensive heat exchanger area for heat transfer > > > > FC: expensive contact area for mass transfer > > > Do you have a point > > It's a request: > > We need something more powerful than Carnot to eliminate fuel-to- > mechanical energy devices that will never work or never work as hoped. Obviously it's going to be longer than Carnot and will probably include generalized material properties. Here's an opportunity to get a dimensionless number named after you. Bret Cahill
From: eric gisse on 27 Feb 2010 16:44 Bret Cahill wrote: > Carnot is almost two centuries old and only covers heat engines. Is a fuel cell a heat engine? There you go. [snip rest]
From: Bret Cahill on 27 Feb 2010 21:36
> > Carnot is almost two centuries old and only covers heat engines. The Pythagorean Theorem is over two millennia old and only covers right triangles. > Is a fuel cell a heat engine? Is a 4 - 5 - 6 triangle a right triangle? Someone came up with the law of cosines to cover _any_ triangle. Similarly someone needs to come up with a maximum limit formula/law/ equation that will cover _any_ mechanism that oxidizes fuel to ultimately produce mechanical work. Bret Cahill |