Joined: Jul 18, 2004 Posts: 198 Location: S. Yorkshire, UK
Posted: Sat Jul 02, 2005 4:25 pm Post subject:
While it is certainly true that hydrogen has the highest energy to mass ratio for any chemical fuel. This doesn't hold when the mass of the storage container is taken into account.
Storing liquid hydrogen requires moderate pressure heavily insulated tanks. Holding gaseous hydrogen requires enormous pressures and immensely strong tanks. Metal hydrides may allow a lower pressure at the cost of a the weight of the matrix metal.
With current hydrogen storage technologies, the energy to mass ratio is worse than for current petroleum based fuels (which require minimal containment). It is possible that development of improved storage techniques allows a large hydrogen powered aircarft to be lighter than an petroleum powered one. But even this will be offset by the enormous volume required for the hydrogen, and therefore increased drag.
Just saw this as well: link
Surely , in a post peak world, these will just be toys of the super uber rich.
The link you provided is to a story on building an aircraft using hydrogen fuel cells to turn propellors. This is a vastly different (and fair more expensive) approach than what Airbus is doing. The Airbus project is about burning hydrogen in a more-or-less conventional jet engine. My opinion is that it should work quite well. The major issue is how they manufacture the hydrogen. As others have pointed out, hydrogen isn't a source of energy, it's a means of storing it. You might need some nuke plants to generate the stuff.
Posted: Mon Jul 04, 2005 2:59 pm Post subject: Hydrogen Fuel Cell Vehicle = 10,000 Miles Per Gallon ?
Eco-car more efficient than light bulb
LONDON, England (CNN) -- An eco-car that can travel the world using a fraction of the electricity it takes to power a light bulb, has been unveiled by its British creators.
According to the British gas firm BOC, its hydrogen-powered BOC Ech2o needs just 25 Watts -- the equivalent of less than two gallons of petrol -- to complete the 25,000-mile global trip, while emitting nothing more hazardous than water.
But with a top speed of 30mph, the journey would take more than a month to complete, even if the car was driven flat out with no pit-stops.
On Thursday, the BOC Ech2o will be put to the test in a bid to smash the world fuel efficiency record of over 10,000 miles per gallon at the Shell Eco Marathon at the Rockingham Raceway track in the UK.
The record is currently held by the PAC-Car II, a hydrogen-fuelled Swiss vehicle, that travelled the equivalent of 5,385 km/per litre at a testing track in France.
The BOC Ech2o, which was originally designed to demonstrate fuel efficiency, is a remodelling of the BOC Gh2ost which failed to break the world record in Aberdeen last year.
Unlike most other eco-marathon vehicles that run on petrol or diesel, the BOC Ech2o's driving force comes from electricity, created in a hydrogen fuel cell.
John Carolin, BOC global director sustainable energy, told the UK's Press Association: "It sounds unbelievable how little power is used to keep the BOC Ech2o moving, but it demonstrates the impact of careful design and is a valuable lesson for carmakers in the future.
"The lessons from this and other projects will show that hydrogen fuel cell powered vehicles could be a practical, attractive and a viable economic alternative to diesel or petrol fuelled vehicles." _________________ "The Stone Age did not end for lack of stone, and the Oil Age will end long before the world runs out of oil" ............ Former Saudi Arabian oil minister Sheikh Zaki Yamani,
Another bogus article. The life-cycle efficiency of hydrogen fuel-cell cars is lower than that of biodiesel-hybrid cars. Check this MIT study.
A bogus article? You need some qualifications to call something bogus and you don’t meet the basic criteria. I suggest reading up on the subject a pinch before further comment.
BOC Hydrogen Energy Group Shell Eco-Marathon UK _________________ "The Stone Age did not end for lack of stone, and the Oil Age will end long before the world runs out of oil" ............ Former Saudi Arabian oil minister Sheikh Zaki Yamani,
Yeah, the figures on those that were being talked about were 500 and 1200 MPG, which seems slightly more realistic that the 10,000 MPG, which just seems wrong except for a feather weight thing. It’s an ultra light war go-kart - it's not really a car in the traditional sense. At 500mpg, time you add all the usual seats, luggage space, crash protection and gadgets the weight of the car would go from about (I'm guessing) 25kg to over a ton. You'll be then back down to 60-80MPG. Basic laws of physics always tends to get in the way I’m afraid.
Last edited by Wildwell on Mon Jul 04, 2005 6:14 pm; edited 1 time in total
Joined: Jun 12, 2005 Posts: 4189 Location: 1st territorial capitol of AZ
Posted: Mon Jul 04, 2005 6:14 pm Post subject:
Actually that thing is pretty cool because, a bicyclist can routinely put out 200-250 watts, so powering something like that would be no problem. With the power of the rider. Whose flabby ass needs exercise anyway.
Another bogus article. The life-cycle efficiency of hydrogen fuel-cell cars is lower than that of biodiesel-hybrid cars. Check this MIT study.
It's not really a "bogus article" if the car really gets the mentioned mileage. You are just referring to the fact that hydrogen requires more energy to harvest than oil, thus negating the benefits of using fuel efficient hydrogen cars over their less fuel efficient, gasoline powered counterparts.
You could build a battery electric out of that thing, and throw in a 50 kW drive system, and keep that efficiency at 30 mph, but also see a top speed increase to over 130 mph, outright evil acceleration, and have a well-to-wheels efficiency at least three times higher than the fuel cell car.
However, it's an ugly plastic duck. That's not somethnig that can replace what we drive today.
Electric cars that are actually cars and not plastic bubbles see a batteries to wheel energy consumption of 130 miles per gallon on the low end for trucks and SUVs and 250 on the high end for sports cars and economy cars. This is doable. When you factor in power plant efficiency, transmission losses from the power plant to the outlet, the charger efficiency, and battery efficiency, efficiencies of over 70 miles per gallon are easily doable for electric cars having similar aerodynamics and weight to the hybrids sold today. Cut the aerodynamic drag more by using the body shell from a GM Precept or such, and coal to wheels efficiency of a midsize electric car capable of seating 5 can easily exceed 100 miles per gallon. Keep in mind fuel efficiency for hybrids is calculated tank to wheels. Getting that stored oil refined into gasoline and finally to the car itself has many losses associated with it.
Hydrogen cars are like a battery electric car, only about 1/4 to 1/3 as efficient power plant to wheels due to the inefficiencies associated with creating the hydrogen from water, crude oil, or natural gas, pressurizing it for storage, storing the hydrogen, transporting it, and through the fact that the fuel cell itself isn't going to be more than 50% efficient.
For reference, one gallon of gasoline contains 33,800 Wh of energy. AC Propulsion's TZero from its batteries consumes 150 wh/mile, GM's EV1 130 wh/mile, while an electric Ford Explorer conversion consumes about 330 wh/mile. A pure electric Prius would consume about 200 wh/mile. These figures are in from energy stored in the batteries. _________________ The unnecessary felling of a tree, perhaps the old growth of centuries, seems to me a crime little short of murder. ~Thomas Jefferson
Joined: Jun 28, 2005 Posts: 352 Location: san jose CA
Posted: Tue Jul 05, 2005 8:05 pm Post subject:
Not bad at all, the lack of power and topspeed would make it impractical for any serious useage for the public but at least the technology is making progress. Something with a bit more power and size might be great for purposes for driving and commuting in a large city of for sort trips around town ect.
As it is in its current hydrogen fuel cell state, I think it would make a much better bicycle. There are so many things which incorporating laminar flow can do. www.speed101.com
Bicycles that can be pedalled to over 70 mph on human input alone on flat ground in normal weather? You damn well bet. Such a vehicle fitted with a powerful electric drive and battery pack made and marketed as a high performance motorcycle I think could sell very well. On top of that, it would be covered for bad weather, go like stink, and achieve efficiencies well in excess of 1,000 mpgs. For some people, this would be a solution to their current level of energy consumption, but again, it's not for everyone. I think if our civilization survives the PO crisis to any extent, cars are here to stay, regardless of how many people own and operate them.
Depending on how we approach the PO problem in both manner and speed along with the current progress of the crisis(which is an unknown factor at this time other than it's likely happening now or near now), cars can be sustainable along with some semblance of our current lifestyle. It's all in the economic system. Hard crash or soft landing? Electric vehicles, current status quo, or continuing fuel cell shell game? Oil wars or an end to wars and increase in cooperation? Domination or partnership? Fear or compassion?
It don't matter how PO will turn out, soft landing or hard crash, but I will be certain that if anyone poses a threat to my well-being and survival I won't hesitate to kill them. _________________ The unnecessary felling of a tree, perhaps the old growth of centuries, seems to me a crime little short of murder. ~Thomas Jefferson
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