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#51
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>>I don't have the source of the picture/caption I have (probably from
something like Popular Science), but the sucker is complete with a large steering wheel (yes, a steering wheel), lots of analog gauges covering a whole wall (yes, gauges!), and a maybe 18" teletype tractor feed printer. It's also got a large TV mounted high on a wall.<< BZZZZZZT! Wrong...but thanks for playing. http://www.snopes.com/inboxer/hoaxes/computer.asp |
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#52
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Dave wrote:
> In article >, jim beam > wrote: > > Jim, overall you make some good points. And I do agree that we > should be working on the 10-20-30% improvements that can be had by > conservation, downsizing, hybridizing, etc. But that still puts out > a lot of CO2 and consumes lots of gasoline. So I think it slows > down the looming crisis (if you subscribe to the evidence), but > doesn't halt them. true, but from what i can see, a complete cessation of co2 production is unnecessary. parallel that with things like addressing deforestation and erosion, things that harm natural co2 absorbtion, and we have a more sustainable system. > > >>i'd also consider fuel cells. better conversion efficiency, and the >>fuel supply system is already in place. > > > Gasoline-based fuel cell research has been all-but abandoned. I > could go into the issues, but they are numerous. when federal tax benefits & grants stopped, yes. what are the technical problems? you're probably going to have a butane fuel cell in your laptop before long. > Hydrogen fuel > cells are what all the auto companies are spending their R&D > effort on, to the tune of over $1B. because that's where the federal tax credits are. doesn't mean the decision to subsidize hydrogen research is based on good science. > Note that is corporate > money, not tax payer (though the DOE budget over the next 5 > years is slated at a combined $1.7B or so). but again, that is eligible for 100% write-off is it not? whether the subsidy comes from a direct payout or from 100% write-off, doesn't it amount to the same thing? > Direct methanol may > have small portable application. Large stationary may be natural > gas based. > > Link: > http://www.eere.energy. > gov/hydrogenandfuelcells/pdfs/committee_report.pdf sure, hydrogen fuel cells work, and the by-product is water, but let's address the practical reality: hydrogen is, per kilogram, not as energy dense as gasoline, and somewhat more hazardous in both transportation & storage. what use is hydrogen if you can't safely transport or store it? the space shuttle, which uses liquid hydrogen, has to be fueled as closely as possible before launch to reduce risk & losses. |
#53
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#54
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#55
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#56
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jim beam wrote:
> commute traffic affording known recharge schedules. the current > electric car model [such as it is] is not so great because burning > fossil fuels to generate electricity that charges batteries is only > marginally more efficient than burning the fuel in the car. youd think burning the fuel directly in the car would be the most efficient |
#57
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SoCalMike wrote:
> jim beam wrote: > >> commute traffic affording known recharge schedules. the current >> electric car model [such as it is] is not so great because burning >> fossil fuels to generate electricity that charges batteries is only >> marginally more efficient than burning the fuel in the car. > > > youd think burning the fuel directly in the car would be the most efficient not thermodynamically. or at least, not currently. formula 1 engines are pretty good because they run at real high combustion temps, the key to best yield, but to do that reliably for the mileage of the average family sedan requires expensive and/or different materials. i recall reading some stuff on ceramics in diesel engines, and they allowed both higher combustion temperature [with accompanying increase in efficiency] and a significant increase in service life. but as you may imagine, manufacturers did not show any interest in the last of these two. and to be fair, production cost at that time was very high. but if they had production runs in the millions, that situation would change pretty quick... |
#58
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#59
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#60
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In article >, jim beam > wrote:
>true, but from what i can see, a complete cessation of co2 production is >unnecessary. parallel that with things like addressing deforestation >and erosion, things that harm natural co2 absorbtion, and we have a more >sustainable system. I agree we won't fully cease serious CO2 production, and do not need to. But consider that the number of car owners is going to radically escalate as China, India, and pretty much the rest of the world continues to grow economically. Say we have 2x the miles driven in 2030... [gasoline FC's] >when federal tax benefits & grants stopped, yes. what are the technical >problems? you're probably going to have a butane fuel cell in your >laptop before long. Gasoline FC's require a fuel processor to break the HC into H2 + CO2 and CO, then the CO gets "water gas shifted" to H2+CO2. The first process req's about 700-800C temperature. The latter about 200-300C and is a big reactor. Getting these up to T requires a lot of time and fuel energy (efficiency hit), not practical for room T starting a car in seconds. Any sulfur poisons these reactors, so likely require a sulfur trap (another invention). You'll always have breakthrough impurities that poison the delicate FC catalyst. Can mitigate that at extra cost with a performance hit. You have a very dilute (~40%) H2 stream going to the FC which impacts performance and requires extremely careful flow control to maintain efficiency. Controlling this whole process through typical driving transients is seriously difficult. A big hybrid battery is required. But batteries also aren't very good from freeze conditions, nor cost and weight. Doing a durable, cost-effect FC vehicle working with the ideal fuel H2, is hard enough. The above complicates it so much that this solution, once considered an interim, would probably take many more years to solve than the H2 FC. It isn't impossible, just extremely challenging. >> Hydrogen fuel >because that's where the federal tax credits are. doesn't mean the >decision to subsidize hydrogen research is based on good science. I'm unsure what you mean by "tax credits". I do not think the auto makers are getting any tax credits. And the recently enacted one for end-users is really just a show of support which will not ever amount to any real $ (in the 5 years at least). >> Note that is corporate >> money, not tax payer (though the DOE budget over the next 5 >> years is slated at a combined $1.7B or so). > >but again, that is eligible for 100% write-off is it not? whether the >subsidy comes from a direct payout or from 100% write-off, doesn't it >amount to the same thing? Again, I do not know to what you refer. I do not think the automakers get to write-off any of this R&D. Most of the above $1.7B goes to Nat'l Labs, universities, and specific company research proposals. This doesn't include the huge budgets that the auto companies are expending on their proprietary R&D. >sure, hydrogen fuel cells work, and the by-product is water, but let's >address the practical reality: hydrogen is, per kilogram, not as energy >dense as gasoline, and somewhat more hazardous in both transportation & >storage. what use is hydrogen if you can't safely transport or store >it? the space shuttle, which uses liquid hydrogen, has to be fueled as >closely as possible before launch to reduce risk & losses. Per kg, it is actually the best. It's the per volume where it, uh, has issues :-) As to safety, many safety certifying agencies (German TUV, both US and Japan DOT, etc) have certified the new 10Kpsi tanks. Liq H2 has a boil-off issue which is more about loss of the fuel (which quickly dissipates) than about safety. I'd be more afraid of the Shuttles liq O2! Yes, H2 has a low ignition E, wide flammability limits, and permeates through most anything. Actually its high diffusivity can help as it dissipates very quickly as opposed to gasoline vapors which can collect making a very dangerous situation. I'm confident we can engineer safe H2 systems. The real Q is can we store enough, *cheaply* to satisfy customer range req't. I think H2 concerns are more myth ("Hindenburg") and the devil we don't know. Not to say there aren't issues. But if one proposed gasoline today, it would never happen. Just 100 years of engineering, and user experience (thus comfort), makes it palatable. |
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