| RE:Hydrogen again |
Subject: RE:Hydrogen again by Slalom4me on 2008/2/12 21:41:39 Quote:
Ok, - 700 Watts - per - 52.8 gal. - Or 75.43 gal H2O - per - kW. According to my dictionary, an SI Watt is a unit of electrical power, not a rate. Watts = Amps x Volts. The non-SI unit known as a Watt-hour is a unit of energy. A thousand Watt-hours (kW) is the amount of energy equivalent to a power of 1000 Watts running for 1 hour. Going back to the Toshiba Fuel Cell. It seems to be that the rate is 52.8 US gal (200 L) per 700 W. Regardless of whether 700 W is produced in a minute, an hour, a day or whatever - for 700 W, 52.8 gal is expelled by the process. Consider the chemical reaction (reverse electrolysis of water). In this reaction, H combines with O, releasing H ions, creating H2O and heat. I interpret from this that a given input of H results in a fixed output of H2O. The output of Watts is dependent on the efficiency of the reaction and efficiency determines the ratio of water per Watts produced but my vote is that time is not a factor in the relationship. Regarding efficiency of the Toshiba Fuel Cell. Your approximation of 30% is in the zone. The Toshiba FC is cited as having improved to 38% in 2004 from 28% in 2000. 38% is quite a distance from the optimum efficiency of 83% claimed for fuel cell technology in ideal conditions, but progress is being made. A claim is made that real fuel cells "are still much more efficient than any electric power plant that burns a fuel." The foundation for this is that unlike a heat engine, the FC is not constrained by the Second Law of Thermodynamics. Thanks for the link to the Q&A about water produced by burning gasoline. Darrin Wagner's response advises to consider the effect of incomplete combustion and the lessening of H2O as a result of the by-products, CO in particular. 94z07 - While the fuel cell's only by-products are water and heat, auto exhaust has the following in various ratios. From Wagner's comments, these all contribute to reducing the amount of water generated by an internal combustion engine. - Carbon monoxide CO - Nitrogen dioxide NO2 - Nitrogen monoxide NO - Sulfur dioxide SO2 - Suspended particles - Benzene C6H6 - Formaldehyde COH2 - Polycyclic hydrocarbons Thanks to everyone who is contributing toward helping me understand whether there really is any issue regarding substantially more water being output from a hydrogen fuel cell-powered vehicle in winter driving conditions, compared to a conventional IC engine. . |
