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Muchablat t1_iya52dt wrote

Now it’ll be interesting to see how aircraft will store hydrogen fuel.

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UnCommonSense99 t1_iya9o1e wrote

Lol it's almost impossible to store enough hydrogen on a jet plane to fly a long way unless you get rid of the passengers.

This stuff about hydrogen planes is basically green washing

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Deranox t1_iyanz9c wrote

Yes, all manner of highly intelligent people work on this for years only to green wash us. Mobile phones were huge bricks, look at them now. When there's will, there's improvement and results.

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Kelmon80 t1_iycy2w0 wrote

Improvement is neither automatic nor always possible.

There is a limit to which you can compress hydrogen, and there are limits to how strong a pressure vessel needs to be (read: How heavy it will be).

Cars need about 100kg of tank to store 5kg of hydrogen.

A 737 can carry about 25.000l of fuel, with fuel tank weight more or less negligible, which is around 20 tons. Let's say 22 to account for the tanks as well.

Let's assume a sort of "worst case" - for safety reasons, car-sized hydrogen tanks are used for planes. A full tank being 105kg, this gives you 210 tanks on the plane, for a total of around 1050kg of hydrogen. So about 1/20th the weight in jet fuel. As Hydrogen has three times the energy density as jet fuel, that still leaves you with range reduction of 1/6th, at same load for the plane. And you probably lose quite a bit of space in the plane to accomodate all those small tanks.

Now the best case: You somehow fit two huge pressure vessel into the plane that carry all the hydrogen, and they are of the same shape and weight as the original fuel tanks, but (magically) are at a pressure high enough to get the hydrogen close to its boiling point - 25.000l of it will still be just around 1800kg, or 1/11 the weight of jet fuel, or a 4-fold reduction in flight range - but with the added bonus of also having a much lighter plane, buying you more range. Still, I doubt even in this magically ideal case, you get more than half the original range out of it.

The bottom line is that physics can't be cheated. A hydrogen plane *will* have a far lower range unless you're willing to allocate a considerable amount of additional space for hydrogen storage.

Mind you, that would still make them an interesting alternative on short-range flights, just not an universal replacement.

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UnCommonSense99 t1_iyernee wrote

All sorts of intelligent people worked on the Microsoft Zune lol

If you want to know why hydrogen wont- work as an aircraft fuel you should Google volumetric energy density

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r448191 t1_iybv6ge wrote

Right because there are no dead ends in science... /s

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virgilreality t1_iyb22t2 wrote

I'm wondering about the implications on fuel storage.

Can we compress hydrogen enough to get sufficient fuel onboard a plane for a decent flight time?

Would the necessarily higher compression require more sturdy pressure vessels, and wouldn't the added weight counteract any savings?

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XD332 t1_iya76nh wrote

Would be so sweet if these created an artificial rain drizzle. I live under a flight path so I wouldn’t have to water my garden as much. Lol

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TheXenoRaptorAuthor t1_iyb9hog wrote

Anyone else see news like this and get instantly reminded of that scene in Iron Man where they talk about the arc reactor as a thing they built to shut the hippies up?

1

KittyBizkit t1_iya7ffg wrote

I highly doubt this would be more efficient than using the hydrogen in a fuel cell and running an electric motor with it. I would love to be proven wrong though if anyone has a credible source.

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NellikFPV t1_iyb4mvv wrote

After a quick bit of Googling it seems commercial fuel cell efficiencies are around the 60% mark (minus electrical losses) with room to improve. Modern jet engine thermal efficiencies are generally around 50-55%. So yeah fuel cell probably could win but would essentially require re-engineering the entire propulsion system. Faster/cheaper to just adapt and recertify exiting engine designs and focus all that engineering effort on designing/certifying aircraft to carry cryogenic/10,000psi hydrogen tanks!.

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Dav3le3 t1_iybyl2r wrote

Might also be lighter for the same engine power.

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JustHereToGain t1_iy97ko7 wrote

Does it shoot out water vapor? Cause that would be bad

Edit: It shoots out water vapor, so not really a great alternative

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Orvanis t1_iy9adh2 wrote

Can someone explain why this is bad...? Seems like shooting water into the air would be significantly less bad than current jet engines

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JustHereToGain t1_iy9b2rh wrote

Water vapor in aviation is estimated to play a huge roll in the greenhouse effect. Most estimations rate it as damaging to the climate as the emitted CO2 or even higher. And that's just from the halo effect of normal planes. Now imagine the impact if it actively shoots out more water.

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MrHazard1 t1_iy9zfq1 wrote

But it's much better in the long term, because co2 is not condensible. The water vapor will relatively soon condense back to water, while co2 remains in the atmosphere for many years and just keep cumulating

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Hibatica t1_iy9c8gt wrote

Also, at the height planes fly, not much water naturally makes it up there, right?

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