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/
