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Old 05-08-2009, 10:07 PM   #73
Bimmerman
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Join Date: Dec 2004
Location: Bouncing off the Rev Limiter
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Quote:
Originally Posted by Darth_Yuthura View Post
Since some have complained about my nonsense, I'm going to complain about someone else's nonsense to show that I can and do evaluate the OPPOSITE side of the argument before I make a judgment. So I'm going to attempt to advocate FOR something I don't believe to show just how much my convictions are really 'nonsense.'
If this is in regards to the split-cycle engine thing, that actually looks to have some serious development time put into it, and may actually happen. It's interesting enough that it's getting talked about quite frequently here....it just needs to be cost effective and make good on its claims. Neither have been met yet. Anyway, on to your 'nonsense.'

Quote:
Originally Posted by Darth_Yuthura View Post
Hydrogen fuel cells for automobiles:

This is a potentially everlasting fuel source for automobiles, but it depends upon another energy source to be produced. Nuclear, coal, wind, solar... all could be used for vehicles using hydrogen as a catalyst. Electricity is dependent upon either expensive batteries, or upon a physical connection to a power grid. In addition is that batteries take a long time to charge, but gasoline and liquid hydrogen take only about 5 minutes to replenish.
First, hydrogen as a fuel cell source is decades in the future for a nationally viable infrastructure. I am fully aware of the Honda FCX and such, but there is no infrastructure to make them accepted, and they cost far too much. We need a dual-fuel, a "flex fuel" if you will, hydrogen and gasoline vehicle to create the demand for the infrastructure (i.e. BMW's Hydrogen 7). Only then will fuel cells take off.

My proselytizing aside, the concept of hydrogen as a fuel is sound....generally. People have latched onto the idea of pouring water into your tank, and using it to create hydrogen to create fuel. There are several things wrong with that.

1) it takes more energy to break the OH bonds in water than you get by using the hydrogen in fuel cells. Without a catalyst, you will never break even.
2) you need some kind of liquified hydrogen (extremely cold) or highly pressurized hydrogen. Both have advantages and disadvantages.

Quote:
Originally Posted by Darth_Yuthura
No emissions other than water vapor:

There are actually emissions that come from this fuel, but they originate from locations other than where the cars operate. A nuclear plant can be built in a public location, but coal could be 1000 miles away and the electricity could be transmitted via power lines. Hydrogen fuel is produced using that electricity and then transported via pipeline to fuel station. Cars powered by gasoline produce emissions on sight where hydrogen's emissions can be placed elsewhere.
There are more emissions than you know of, both of fuel cell car, network, gasoline car, and fueling. If you want to be completely correct, look at the wheel to wheel cost of emissions. It's higher than you think.

Quote:
Originally Posted by Darth_Yuthura View Post
Gasoline is only 30% efficient:

Internal combustion engines are only 30% efficient and can't be pushed passed that rating, so even with the loss of energy through hydrolysis, the larger the scale of the power plant, the more efficient it becomes.
You've never taken thermodynamics, have you?

Your statement is ridiculously false. Gasoline engines are only about 35% efficient. However, if you are right, how does a modern V16 in a Bugatti Veyron make 100x more horsepower and get about double the fuel economy of a 1909 Ford Model T inline four cylinder?

The thermodynamic efficiency can be increased by several means. Turbos, supers, nitrous, are just one way. Improving the volumetric efficiency (how well the engine flows, and burns, that air fuel mixture) is a key one. How else would a Formula 1 engine 2.4L V8 make 780 horsepower (without turbos) at 18000 rpm and get 5 mpg? My Suburban never got above 8 mpg, and it was a 5.4L V8.

Furthermore, you will be astonished to learn the efficiency of a modern coal power plant.

Ready?

Do you think it's....75%?



65%?



55%?



Nope. it hovers between 38 and 45% efficient, at best. That goes for any plant that uses steam and turbines; Nuclear, coal, etc all are the same for thermodynamic efficiencies.

I sincerely hope you mean electrolysis to get the hydrogen. It's only feasible when the plant is producing excess energy, as no matter how much you cross your fingers and pray, breaking the water molecules into H2 and O2 consumes more energy than you will gain.

Quote:
Originally Posted by Darth_Yuthura
Storage:

Electricity can't be stored on a large scale, so any excess energy produced from the US power grid is wasted. Hydrogen could take the excess energy and be used where that energy would otherwise be wasted. Batteries are expensive for electric cars, but hydrogen is dependent upon the size of the tanks. That is cheaper than with more batteries.
This doesn't make sense. "Hydrogen could take the excess energy and be used where that energy would otherwise be wasted." ....um...what? The energy content of hydrogen, for combustion, is the highest for any molecule or compound.

Quote:
Originally Posted by Darth_Yuthura
Universal:

The US has enough coal to last hundreds of years, but most American vehicles can't use anything that doesn't come from petroleum. This would allow for almost any form of energy to be interchangeable to be used for transportation.


So, how many people think this is nonsense?
I think there are serious flaws in your sources or your influences. Much of your post makes no sense whatsoever. I welcome a change to hydrogen, and am hoping the duel fuel hydrogen cars (aformentioned Hydrogen 7) make a large inroad into the market to spur demand for hydrogen internal combustion cars and thus create the infrastructure necessary to eventually transfer over to fuel cells.

Whether that happens, though, is anyone's guess.


A racing addiction makes a crack addiction look like a vague desire for something salty. -Randy Hickman

Fear disturbs your concentration. - Sabine Schmitz
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