Re: [Biofuel] H2 Fuel Cell Efficiencies (was Water Powered Engine / Electrolysis)
Quoting robert and benita rabello [EMAIL PROTECTED]: Darryl McMahon wrote: Kirk, those efficiency numbers look like the DOE short term targets from when I was researching my book. I see they are still counting waste heat as part of the efficiency (CHP). Sorry to butt in Darryl, but that seems to be part of the sales presentation, right? Efficiency depends on what we're counting. The numbers for the PEM cells (of which I am most familiar) might be a bit high, but don't seem unreasonable. Robert, you're always welcome to join an on-list conversation (as is anyone else). I agree that pumping up the numbers is an accepted sales technique (if regrettable), however, these figures are coming from the U.S. Department of Energy, who, IMHO, should not be selling the technology. As for being a bit high on efficiency, that's a key issue. As a taxpayer-funded entity, they should be impartial and as accurate as possible. Would it be OK for me to promote an electric resistance heater as being 105% efficient? It's just a bit high. Seriously, the efficiency numbers are important. The hydrogen energy cycle efficiency is not attractive, and we can't afford the multiple conversion losses no matter what the original primary energy source is. Perhaps more so in light of the David Hughes interview I posted last night. (U.S. is already importing coal and past peak coal. World is past peak oil. North America is past peak natural gas and shortages may be closer than the 7-9 years I had been expecting until now.) Do you know of someone actually selling units with these efficiencies (validated by third parties and guaranteed to clients by vendors) in the commercial market? Even if a company WAS selling one of these things, they certainly wouldn't sell one to you or me!!! (The same is true of commercial electrolyzers.) Actually, there have been companies that were selling home electrolyzers in the past (Billings comes to mind), the the hydrogen herd certainly has been promoting home scale fuel cells as part of the H2/distributed generation vision (although I'm not aware of any targeted at this segment and on the market today). Stuart Energy/Electrolyzer Corp. did have some small electrolyzers advertised a few years ago, probably a bit large for a single house, but perhaps appropriate to the rowhouse / small apartment building scale. IIRC, there is (was?) a demonstration house in Thailand that has a household scale fuel cell (sorry, I don't have a reference handy), but I think the solar PV and vanadium flow battery demonstration was considered the greater success. As for not selling to you and me, I think pricing just might be a factor in that. Darryl -- Darryl McMahon The Emperor's New Hydrogen Economy http://www.econogics.com/TENHE/ ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
Re: [Biofuel] H2 Fuel Cell Efficiencies (was Water Powered Engine / Electrolysis)
I saw a Canadian outfit but didnt bookmark it. They were selling to industrial users. Home use means unskilled in maintenance so I am not sure how they will cross that bridge. Kirk Darryl McMahon [EMAIL PROTECTED] wrote: Kirk, those efficiency numbers look like the DOE short term targets from when I was researching my book. I see they are still counting waste heat as part of the efficiency (CHP). Do you know of someone actually selling units with these efficiencies (validated by third parties and guaranteed to clients by vendors) in the commercial market? The disadvantages make interesting reading though, don't they? Darryl __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
[Biofuel] H2 Fuel Cell Efficiencies (was Water Powered Engine / Electrolysis)
Kirk, those efficiency numbers look like the DOE short term targets from when I was researching my book. I see they are still counting waste heat as part of the efficiency (CHP). Do you know of someone actually selling units with these efficiencies (validated by third parties and guaranteed to clients by vendors) in the commercial market? The disadvantages make interesting reading though, don't they? Darryl Kirk McLoren wrote: * Comparison of Fuel Cell Technologies * * Fuel Cell Type * * * * Common * * * * Electrolyte * * * * Operating Temperature * * * * System Output * * * * Efficiency * * * * Applications * * * * Advantages * * * * Disadvantages * Polymer Electrolyte Membrane (PEM)* Solid organic polymer poly-perfluorosulfonic acid 50 - 100°C 122 - 212°F 1kW – 250kW 50-60% electric • Back-up power • Portable power • Small distributed generation • Transportation • Solid electrolyte reduces corrosion electrolyte management problems • Low temperature • Quick start-up • Requires expensive catalysts • High sensitivity to fuel impurities • Low temperature waste heat Alkaline (AFC) Aqueous solution of potassium hydroxide soaked in a matrix 90 - 100°C 194 - 212°F 10kW – 100kW 60-70% electric • Military • Space • Cathode reaction faster in alkaline electrolyte so high performance • Expensive removal of CO_2 from fuel and air streams required Phosphoric Acid (PAFC) Liquid phosphoric acid soaked in a matrix 150 - 200°C 302 - 392°F 50kW – 1MW (250kW module typical) 80 to 85% overall with combined heat and power (CHP (36-42% electric) • Distributed generation • High efficiency • Increased tolerance to impurities in hydrogen • Suitable for CHP • Requires platinum catalysts • Low current and power • Large size/weight Molten Carbonate (MCFC) Liquid solution of lithium, sodium, and/or potassium carbonates, soaked in a matrix 600 - 700°C 1112 - 1292°F 1kW – 1MW (250kW module typical) 85% overall with CHP (60% electric) • Electric utility • Large distributed generation • High efficiency • Fuel flexibility • Can use a variety of catalysts • Suitable for CHP • High temperature speeds corrosion and breakdown of cell components • Complex electrolyte management • Slow start-up Solid Oxide (SOFC) Solid zirconium oxide to which a small amount of yttira is added 650 - 1000°C 1202 - 1832°F 5kW – 3MW 85% overall with CHP (60% electric) • Auxiliary power • Electric utility • Large distributed generation • High efficiency • Fuel flexibility • Can use a variety of catalysts • Solid electrolyte reduces electrolyte management problems • Suitable for CHP • High temperature enhances corrosion and breakdown of cell components • Slow start-up */http://www.eere.energy.gov/hydrogenandfuelcells/fuelcells/fc_types.html/* *//* */pdf link at bottom of page/* *//* */Kirk/* *//* *//* *//* */Chip Mefford [EMAIL PROTECTED]/* wrote: Kirk McLoren wrote: Fuel cells of 50% efficiency can be purchased now. Really? Where? -- Darryl McMahon It's your planet. If you won't look after it, who will? The Emperor's New Hydrogen Economy (now in print and eBook) http://www.econogics.com/TENHE/ ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
Re: [Biofuel] H2 Fuel Cell Efficiencies (was Water Powered Engine / Electrolysis)
Darryl McMahon wrote: Kirk, those efficiency numbers look like the DOE short term targets from when I was researching my book. I see they are still counting waste heat as part of the efficiency (CHP). Sorry to butt in Darryl, but that seems to be part of the sales presentation, right? Efficiency depends on what we're counting. The numbers for the PEM cells (of which I am most familiar) might be a bit high, but don't seem unreasonable. Do you know of someone actually selling units with these efficiencies (validated by third parties and guaranteed to clients by vendors) in the commercial market? Even if a company WAS selling one of these things, they certainly wouldn't sell one to you or me!!! (The same is true of commercial electrolyzers.) robert luis rabello The Edge of Justice The Long Journey New Adventure for Your Mind http://www.newadventure.ca Ranger Supercharger Project Page http://www.members.shaw.ca/rabello/ ___ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
