Turbines for hydrogen fueled cars?

RGClark

The energy density usually given for hydrogen is 142 MJ/kg, by which comparison is made to how much hydrogen would have to be carried for it to be competitive with gasoline-fueled vehicles:

Bottling the hydrogen genie.
"One kilogram of hydrogen provides about the same chemical energy (142 MJ) as 1 gal of gasoline (131 MJ). Factoring in the greater efficiency of PEMs [fuel cells], we need to store about 1 kg of hydrogen for every 2 gal of gasoline on a similar internal-combustion-engine vehicle."
http://www.tipmagazine.com/tip/INPHF...iss-1/p20.html

But one of the storage methods is by high pressurization. Quantum Technologies has a hydrogen tank that can store hydrogen at 10,000psi.
But the energy density quoted of 142 MJ/kg does not take into account how much extra energy is added by the high pressure. It seems to me you should get more energy out by using this high pressure.
Let's say you have 8 kg of hydrogen stored at 10,000 psi and 300K temperature. There is deviation from the ideal gas law at this pressure and the density is only about 32kg/m^3. See the hydrogen properties here:

Hydrogen Properties Package.
http://inspi.ufl.edu/data/h_prop_package.html

What kind of power could you get from a turbine using hydrogen at this high pressure?
What other methods could you use to get useful work out of this high pressure?



Bob Clark

willib

I agree , why use hydrogen fuel in an obslolete internal combustion engine , thats silly.. when they allready stated that a hydrogen fuel cell is very efficient ..
so hydrogen goes in the "tank" a fuel cell charges batteries , batteries power car....seems simple enough ..

hitssquad

Fuel cell cars are not more efficient than gasoline-powered reciprocating-heat-engine cars.
http://www.evworld.com/view.cfm?sect...le&storyid=730

Ivan Seeking

Also, there are practical problems with fuel cells, such as cost, that help to drive internal combustion engines a viable option.

I also think the energy price for producing fuel cells is not properly recognized - the evidence for this is found partly in the dollar price. Ultimately, cost is a function of the energy put into a device. Also, what about the energy costs of recycling the fuel cells?

willib

i did not read any proof that fuel cells are not more efficient than internal combustion engines , sorry , but it seemed to me that this one guy doesnt like fuel cells , for some reason...
eg. he mentions using an inverter to convert the power from the fuel cells ..???
this tells me that he doesnt know what he is talking about..because an inverter converts DC to AC , which isnt needed at all .. because any electric car ever made runs on DC...

MR. P

I don't necessairly agree wtyh the fuel cell alternative.

I believe detonation tech technologies may offer the best 'bang' for the buck.
We are currently evaaluating a modified APU utilizing a 'drag' (Tesla) approach for a baseline determination. some pics at :

www.windtohydrogen,com or www.parsonsenergy.com

MR. P

Thank you Ivan ....makes being wrong ~accecptable????
my problems orient around spelling, syntax and grammar.....I can make acronyms

willib

I never said i was against turbines , in fact i was thinking of how one could use a small turbine to generate power to charge a battery bank for todays honda & toyota electric cars .thus eliminating the internal combustion engin compleatly.. as i have found out , through experimentation, the faster a generator spins the more power you can get out of it.. i've wondered how a generator specifically designed to operate at turbine speeds , approx 100,000 RPM , would do?

MR. P

RG:
We've been experimitting with various small gas turbine sonerios 'boundary layre drag'(Tesla) hybrid configuration. We're using 30, 4 1/4 " disks for the compressor side however the turbine side wasn't developing enough horsepower to stay lit so we're machining a new hotwheelheel from a cat turbo...
preliminairily We don't believe that the pressure developed by a normal comptocombustiondilutiontoturbine will be very efficient.
the reason we wanted a bladeless turbine at least as a first stage is to homoginize pressure fluctustions resulting form an experimen5tsl up stream detonator i have some pics and vids at
ww2w.windtohydrogen.com or www.parsonsenergy.com

Clausius2

This time I totally agree with hitssquad. Some problems cause that Fuel Cells are not currently appropriated for its implementation into car engines:

Although the efficiency of an isolated Fuel Cell could be greater than a heat engine, a Fuel Cell used for automobile propulsion is less efficient than a heat engine. Hydrogen is a substance which is not easily obtained in pure state, or its obtention hasn't got the environmental efficiency required for a traditional fuel substitution. So that it is needed a previous reformer which extracts hydrogen of the fuel. Currently a Fuel Cell applied to an automobile has an efficiency of approximately 30%. That's because it is needed a cooling pump (the cell gets very hot), energy flow to the reformer, and control systems. Also the dynamic behavior of Fuel Cell is very slow. A heat engine has a fast response when the throttle valve/fuel injection is being varied. That's a point that engineers must take into account: how is the whole vehicle going to response dynamically?. The answer is worse than with a heat engine.

The solution to the problem of Hydrogen production is an unknown. Electrolysis is a very inefficient process. Another methods such as CO2 sequestration has high costs nowadays.

Also we could talk about security. You know, RGClark, storaging Hydrogen at high pressures and transporting it into a car is not a good thing. It is a bomb. The Hydrogen burns rapidly when it flows into air.

It must be considered the GLOBAL efficiency of energy conversion, from the gas source to the wheel, (which americans call "wheel to wheel efficiency"). Nowadays the low efficiency of Hydrogen obtention could be balanced by the high efficiency of the Fuel Cell.

Cliff_J

The GM EV1 and now the T-Zero from some of the original team members on the EV1 project are AC. It seems to make sense to use a PMDC but they must have had a compelling reason to not use one.

And if safety in a crash is concerned a gasoline tank makes for a good bomb and easily started long-lasted fire. At least H2 travels up with the flame and burns out quickly, and I believe it was BMW who has demonstrated some lab testing footage that reinforces that idea. Just think how little fire even the Hindenburg would have presented to the people below it had the covering not been a fabric doped with petroleum based products and it was only the H2 burning.

Ivan Seeking

It can be reaonably argued that H2 storage is inherently safer that gasoline tanks. We drive around with bombs now. Hydrogen dissapates quickly and rises. Gasoline remains in liquid form and burns everything in site. There is a real test of this shown at the National H2 Assoc. web site. http://www.hydrogenus.com

Of course H2 storage as a hydride seems very promising. This eliminates the danger completely, or nearly so.

Ivan Seeking

Here is the Hydrogen Safety Fact Sheet:
http://www.hydrogenus.com/H2-Safety-Fact-Sheet.pdf

FredGarvin

My company did a concept car for GM back in the 70's using a turbine driven alternator. It ran like a dream. I would be happy as all get up if we could resurrect that program.

The three big things about H2 in vehicles that I worry about are 1) the need for proper grounding when working around vapors. People today don't pay any attention to this when they fill their tanks with petroleum fuels as is. With hydrogen, that risk becomes greater. The concentration range of H2 when mixed with air can vary hugely and still ignite very easily with very little spark energy. 2) Hydrogen migrates so quickly it is more of an asphyxiation risk than gasoline. 3) Some hydrogen fires can burn invisibly or darned close. I think that other parts of the infrastructure like service stations, firefighting and others are all going to implement some drastic changes when hydrogen vehicles come on line. There's going to be a big learning curve.

RGClark

Do you know what link the video is located at?


Bob

willib

Those Wren turbines discussed in another thread on PF, use only
55 mL fuel at Idle thrust 2.5N at 45,000 rpm..Hence my question on the Thrust/ Watt correlation..
OK this is just an idea .. but what if we could use some sort of alcohol/corn oil combination , to run the turbines ,to run the generators ,to charge the batteries , in our future automobiles ..Both are regenerate-able sources of fuel.. and both pack a lot of power (BTU)..