I was going to start a new thread re 'Power Paste', which I was reading about this morning, but being a new format of hydrogen fuel, it ties in here.
hydrogen-paste-a-new-fuel-option-for-vehicles
Seems promising?
-------------------------------------------------------------------------------------------------------------
Presumably Aussies can use Vegimite instead? :-)
Seriously though, unless the electrolysis and sea water desal processes can be improved significantly to not use a load of energy, all this sort of thing is doing is transforming energy from one form to another and wasting a decent amount each time that occurs.
I don't know or really understand the technical side of things, but this is what was written;
"Onboard the vehicle, the PowerPaste is released from the cartridge by means of a plunger, when water is added from an onboard tank, the ensuing reaction generates hydrogen gas. In fact only half of the hydrogen originates from the PowerPaste, the rest comes from the added water. PowerPaste thus has a huge energy storage density, substantially higher than that of a high pressure storage tank. And compared to batteries, it has 10 times the energy storage density. This means it offers a range comparable to-or even greater than-gasoline. And the paste doesn't need any infrastructure: when you need to refuel, you just buy a new cartridge from, well, anywhere, including the corner shop"
Depending on cost, this sounds like a much better solution than current fuel cell refuelling, and could well be a better option than (battery) EV's, certainly for bigger mileage drivers.
The journalist who penned this, headlines the page;
"Now everyone has bet the farm on battery EV's. But sometimes everyone's wrong"!
Edited by badbusdriver on 25/06/2021 at 11:29
|
|
A fundamental physical law relates to conservation of energy. Energy is a constant which cannot be created or diminished.
No one has iinvented a perpetual motion machine (despite lots of efforts and scams) - one which in operation produces enough energy to power itsself indefinitely. Every time energy is used or converted from one form to another there are losses which are not recovered.
Comparison of different (eg: ICE vs H2 vs battery) technologies is made more complex as environmental and financial concerns often dominate energy efficiency issues.
At a simplistic level H2 generation is either non-green or uses electricity (xx% efficiency losses). Reciprocating engines are inherently inefficient.with efficiency losses as H2 is burnt. In a fuel cell to regenerating electricity involves efficiency losses as H2 is converted.
H2 may find a niche in HGVs, and possibly vehicles which genuinely required long range/quick refuel capacity. The private motorist may find battery technology continuing to outpace H2 development. Military and aviation uses may be the principle exception.
|
H2 may find a niche in HGVs, and possibly vehicles which genuinely required long range/quick refuel capacity. The private motorist may find battery technology continuing to outpace H2 development. Military and aviation uses may be the principle exception.
This is pretty much what I think - for private motorists battery range is increasing and faster charging batteries are on the way - so for the majority electric cars are the future. Most people when talking about electric vehicles worry about range and charging - so with those problems bing sorted then I can see no reason for most people not to go that way.
|
|
|
|
I was going to start a new thread re 'Power Paste', which I was reading about this morning, but being a new format of hydrogen fuel, it ties in here.
hydrogen-paste-a-new-fuel-option-for-vehicles
Seems promising?
-------------------------------------------------------------------------------------------------------------
Presumably Aussies can use Vegimite instead? :-)
Seriously though, unless the electrolysis and sea water desal processes can be improved significantly to not use a load of energy, all this sort of thing is doing is transforming energy from one form to another and wasting a decent amount each time that occurs.
I don't know or really understand the technical side of things, but this is what was written;
"Onboard the vehicle, the PowerPaste is released from the cartridge by means of a plunger, when water is added from an onboard tank, the ensuing reaction generates hydrogen gas. In fact only half of the hydrogen originates from the PowerPaste, the rest comes from the added water. PowerPaste thus has a huge energy storage density, substantially higher than that of a high pressure storage tank. And compared to batteries, it has 10 times the energy storage density. This means it offers a range comparable to-or even greater than-gasoline. And the paste doesn't need any infrastructure: when you need to refuel, you just buy a new cartridge from, well, anywhere, including the corner shop"
Depending on cost, this sounds like a much better solution than current fuel cell refuelling, and could well be a better option than (battery) EV's, certainly for bigger mileage drivers.
The journalist who penned this, headlines the page;
"Now everyone has bet the farm on battery EV's. But sometimes everyone's wrong"!
I remain to be convinced about this 'power paste'. As it's not a proper liquid, it would need something akin to an augur rather than a pump, which (as with wood pellet/chip boilers) needs more significant maintenance than liquid or gas-fired ones.
I'm also unsure how a person would remove the 'old cartridges' (which still would be large, like an ink cartridge the size of a petrol tank) easily (heavy and location) and without creating a (possibly dangarous) mess around the connection point.
Still, I'm curious to know more to see what the developers have come up with. It still doesn't get around the hdrogen generation issues I've talked about though. I also would bet the paste production process uses quite a bit of energy too.
We need a Mr Fusion device! :-)
|
|
Any scientist worth his \ her salt, will tell you hydrogen is unsuitable to power vehicles except HGVs and trains.
Despite HJ repeatedly pushing hydrogen, it's not a good source of instanteous power. But mugs will still shout for it.
|
Any scientist worth his \ her salt, will tell you hydrogen is unsuitable to power vehicles except HGVs and trains.
Despite HJ repeatedly pushing hydrogen, it's not a good source of instanteous power. But mugs will still shout for it.
The hydrogen is just producing electricity, so I don't see why it is suitable for an HGV but not for a car?
|
Any scientist worth his \ her salt, will tell you hydrogen is unsuitable to power vehicles except HGVs and trains.
Despite HJ repeatedly pushing hydrogen, it's not a good source of instanteous power. But mugs will still shout for it.
The hydrogen is just producing electricity, so I don't see why it is suitable for an HGV but not for a car?
And regarding trains, they already have the ideal power source, electric motors producing a huge amount of instant torque, the set up has worked well for years. Unless you wanted a cleaner alternative to diesel on lines that are not electrified.
|
And regarding trains, they already have the ideal power source, electric motors producing a huge amount of instant torque, the set up has worked well for years. Unless you wanted a cleaner alternative to diesel on lines that are not electrified.
in which case hydrogen fuel cell trains already exist although they too have their limitations (fuel storage/sourcing, speed)
|
|
|
|
Any scientist worth his \ her salt, will tell you hydrogen is unsuitable to power vehicles except HGVs and trains.
That demonstrates a complete lack of understanding of science and scientists, never mind knowledge of hydrogen usage.
|
Any scientist worth his \ her salt, will tell you hydrogen is unsuitable to power vehicles except HGVs and trains.
That demonstrates a complete lack of understanding of science and scientists, never mind knowledge of hydrogen usage.
Good grief, no it really doesnt but your response is typical of someone who didnt comprehend my statement nor done their own research on the subject.
Robert Llewellyn had an excellect live debate with a top scientist who went on to explain hydrogen loses a lot of it's efficiency when cooled to a liquid as required for a car, doesnt give up it's energy quickly or efficiently for day to day car driving and, because of it's volatility amongst these issues is best suited to vehicles that require grunt rather than quick acceleration and short stop start use, ergo best suited to trains and HGVs.
Unfortunately I cannot find Robert's excellent debate on YT and can only presume because it was live, he hasnt 'saved' it or else if he has, saved it elsewhere.
Instead, you'll have to make do with Codogan's YT video which you can watch at your leisure instead.
youtu.be/gu1v7d7-Wh0
or this one, if you wish a 'demonstration' of understanding.
youtu.be/b88v-WvqzeQ
And another one.
youtu.be/f7MzFfuNOtY
Edited by glidermania on 25/06/2021 at 23:57
|
Any scientist worth his \ her salt, will tell you hydrogen is unsuitable to power vehicles except HGVs and trains.
That demonstrates a complete lack of understanding of science and scientists, never mind knowledge of hydrogen usage.
Good grief, no it really doesnt but your response is typical of someone who didnt comprehend my statement nor done their own research on the subject.
Perhaps you should offer your services to Toyota. They seem to need your research and expert advice.
Toyota Mirai Review (2021) | Autocar
|
|
|
|
Any scientist worth his \ her salt, will tell you hydrogen is unsuitable to power vehicles except HGVs and trains.
Despite HJ repeatedly pushing hydrogen, it's not a good source of instanteous power. But mugs will still shout for it.
Does von Braun not count? Or is he the exception that proves the rule?
Or perhaps you have secret knowledge that the Apollo missions were faked-up in a hangar somewhere, Capricorn 1 stylee, because they found out that hydrogen was not a good source of instantaneous power after all? Embarrassing.
Edited by edlithgow on 26/06/2021 at 08:43
|
Any scientist worth his \ her salt, will tell you hydrogen is unsuitable to power vehicles except HGVs and trains.
Despite HJ repeatedly pushing hydrogen, it's not a good source of instanteous power. But mugs will still shout for it.
Does von Braun not count? Or is he the exception that proves the rule?
Or perhaps you have secret knowledge that the Apollo missions were faked-up in a hangar somewhere, Capricorn 1 stylee, because they found out that hydrogen was not a good source of instantaneous power after all? Embarrassing.
What I'm unsure about is how trains and HGVs would have any space left for the fuel. Whilst they aren't requiring the huge amount of energy required to get into orbit like a rocket like the Saturn V (bearing in mind the tiny capsule size/weight compared to the fuel tanks and engines), etc, they still require a large amount of power to haul very significant amounts of weight, including up inclines and from a standing start.
Not sure whether the videos glidermania referred to covered storage (including at refuelling sites) and refueling, especially for trains. As I indicated earlier, Toyota had significant issues (far more than they first believed would be the case) trying to make their test car remotely viable, including the amount of refuelling it had to do.
|
|
I've seen the John Cadogan UT video (though not lately) referenced above, and I'd guess he knows what he's talking about, but he doesn't talk about what he says he's talking about.
Its billed (and IIRC titled) as a Hydrogen IC debunk, but in fact its exclusively about reciprocating piston engines. Turbines (as in jet aircraft engines), are not considered, and he'd have trouble claiming its no good in rockets. These are both IC engine types.
Aircraft are a potential application because the weight and range penalties of electric options are currently severe, and the climate effects of burning kerosene at high altitude are disproportionate. That counterbalances the energy conversion losses somewhat, but its probably more practical to use synthetic or biofuel equivalents of existing jet fuel if the objective is to reduce the carbon footprint..
Edited by edlithgow on 26/06/2021 at 14:12
|
I've seen the John Cadogan UT video (though not lately) referenced above, and I'd guess he knows what he's talking about, but he doesn't talk about what he says he's talking about.
Its billed (and IIRC titled) as a Hydrogen IC debunk, but in fact its exclusively about reciprocating piston engines. Turbines (as in jet aircraft engines), are not considered, and he'd have trouble claiming its no good in rockets. These are both IC engine types.
Aircraft are a potential application because the weight and range penalties of electric options are currently severe, and the climate effects of burning kerosene at high altitude are disproportionate. That counterbalances the energy conversion losses somewhat, but its probably more practical to use synthetic or biofuel equivalents of existing jet fuel if the objective is to reduce the carbon footprint..
Not sure that biofuels are viable any more, given they take away huge swathes of arable land that is needed for food production, which will be even more essential as countries should look to be far less dependent on food (and general) imports, which itself is a major contributor to climate change and pollution.
Also unsure how having hydrogen under extremely high pressure in aircraft travelling in a very low pressure environment (i.e. that would encourage leaks) would necessary be the ideal answer either.
|
Not sure that biofuels are viable any more, given they take away huge swathes of arable land that is needed for food production, which will be even more essential as countries should look to be far less dependent on food (and general) imports, which itself is a major contributor to climate change and pollution.
No, they certainly aren't viable - does not make any sense using arable food growing land to grown fuel when you can't get enough energy from the bio fuels.
|
Not sure that biofuels are viable any more, given they take away huge swathes of arable land that is needed for food production, which will be even more essential as countries should look to be far less dependent on food (and general) imports, which itself is a major contributor to climate change and pollution.
No, they certainly aren't viable - does not make any sense using arable food growing land to grown fuel when you can't get enough energy from the bio fuels.
If the global market (constrained a bit, hopefully, by climate change policy) determines that the purchasing power of rich people who want to fly is greater than that of poor people who want to eat, then that's what happens.
Thats the way the system works.
Where have you been?
|
Not sure that biofuels are viable any more, given they take away huge swathes of arable land that is needed for food production, which will be even more essential as countries should look to be far less dependent on food (and general) imports, which itself is a major contributor to climate change and pollution.
No, they certainly aren't viable - does not make any sense using arable food growing land to grown fuel when you can't get enough energy from the bio fuels.
If the global market (constrained a bit, hopefully, by climate change policy) determines that the purchasing power of rich people who want to fly is greater than that of poor people who want to eat, then that's what happens.
Thats the way the system works.
Where have you been?
I have been here, there and everywhere. Where have you been?
At the moment biofuels are not suitable for aviation so a bit of moot point.
|
Not sure that biofuels are viable any more, given they take away huge swathes of arable land that is needed for food production, which will be even more essential as countries should look to be far less dependent on food (and general) imports, which itself is a major contributor to climate change and pollution.
No, they certainly aren't viable - does not make any sense using arable food growing land to grown fuel when you can't get enough energy from the bio fuels.
If the global market (constrained a bit, hopefully, by climate change policy) determines that the purchasing power of rich people who want to fly is greater than that of poor people who want to eat, then that's what happens.
Thats the way the system works.
Where have you been?
I have been here, there and everywhere. Where have you been?
At the moment biofuels are not suitable for aviation so a bit of moot point.
From your post the only place I could think of was Cuba.
I must try and get there before it goes the way of everywhere else, but it might already be too late.
Edited by edlithgow on 28/06/2021 at 03:25
|
Not sure that biofuels are viable any more, given they take away huge swathes of arable land that is needed for food production, which will be even more essential as countries should look to be far less dependent on food (and general) imports, which itself is a major contributor to climate change and pollution.
No, they certainly aren't viable - does not make any sense using arable food growing land to grown fuel when you can't get enough energy from the bio fuels.
If the global market (constrained a bit, hopefully, by climate change policy) determines that the purchasing power of rich people who want to fly is greater than that of poor people who want to eat, then that's what happens.
Thats the way the system works.
Where have you been?
I have been here, there and everywhere. Where have you been?
At the moment biofuels are not suitable for aviation so a bit of moot point.
To point your moot point at someone else, these guys sell the stuff
aviation.totalenergies.com/aviation-businesses/com...n
"Sustainable Aviation Fuel, or SAF, is an alternative to fossil jet fuel which helps to reduce the CO2 emissions generated by air transport. It is already available on the market and can be used in current logistics infrastructure, without any adaptations to existing aircraft and engines."
Shouldn't you out them, and make the customers aware they are flying without suitable means of support? Knowing what you know, how would you feel if one(or all) of them came down, and you had done nothing?
I don't envy you your burden.
This paper attempts to review the market as a whole, including some environmental accounting.
www.frontiersin.org/articles/10.3389/fenrg.2020.00...l
The main obstacles to adoption (apart from the oil palm biodiversity holocaust in SE Asia, which is happening anyway) are not technical, but the inability to compete with kerosene on a cost basis, limiting investment. Ban or ultra tax fossil aviation fuel and the competition goes away.
|
|
Also unsure how having hydrogen under extremely high pressure in aircraft travelling in a very low pressure environment (i.e. that would encourage leaks) would necessary be the ideal answer either.
The pressure at ground level is one atmosphere (bar), the hydrogen pressure in the tanks would be several hundred bar. Hard to see why they would leak more even if the aircraft were in a vacuum (zero bar). At 40,000 feet its about 0.1 bar outside.
|
Also unsure how having hydrogen under extremely high pressure in aircraft travelling in a very low pressure environment (i.e. that would encourage leaks) would necessary be the ideal answer either.
The pressure at ground level is one atmosphere (bar), the hydrogen pressure in the tanks would be several hundred bar. Hard to see why they would leak more even if the aircraft were in a vacuum (zero bar). At 40,000 feet its about 0.1 bar outside.
By your own reckoning, that's 10x less pressure outside. I'd say that's quite a difference.
|
Also unsure how having hydrogen under extremely high pressure in aircraft travelling in a very low pressure environment (i.e. that would encourage leaks) would necessary be the ideal answer either.
The pressure at ground level is one atmosphere (bar), the hydrogen pressure in the tanks would be several hundred bar. Hard to see why they would leak more even if the aircraft were in a vacuum (zero bar). At 40,000 feet its about 0.1 bar outside.
By your own reckoning, that's 10x less pressure outside. I'd say that's quite a difference.
Lets make this really simple, just for you.
Pressure in tank = 700 bar (as in Toyota Mirai)
Outside pressure = 1 bar, tank pressure differential = 699 bar
Outside pressure = 0.1 bar, tank pressure differential = 699.9 bar
Percentage increase in tank pressure differential (ground level to 40,000 feet) = [(0.9/699)*100] which is ~0.13%.
Hope that helps.
|
Also unsure how having hydrogen under extremely high pressure in aircraft travelling in a very low pressure environment (i.e. that would encourage leaks) would necessary be the ideal answer either.
The pressure at ground level is one atmosphere (bar), the hydrogen pressure in the tanks would be several hundred bar. Hard to see why they would leak more even if the aircraft were in a vacuum (zero bar). At 40,000 feet its about 0.1 bar outside.
By your own reckoning, that's 10x less pressure outside. I'd say that's quite a difference.
Lets make this really simple, just for you.
Pressure in tank = 700 bar (as in Toyota Mirai)
Outside pressure = 1 bar, tank pressure differential = 699 bar
Outside pressure = 0.1 bar, tank pressure differential = 699.9 bar
Percentage increase in tank pressure differential (ground level to 40,000 feet) = [(0.9/699)*100] which is ~0.13%.
Hope that helps.
Hydrogen fuelled deep ocean submarines (say a SuperTrieste) wouldn't need pressure tanks at all.
I suppose you'd have to fill them down there though.
Tricky.
Electrolysis and a long cable?
|
Also unsure how having hydrogen under extremely high pressure in aircraft travelling in a very low pressure environment (i.e. that would encourage leaks) would necessary be the ideal answer either.
The pressure at ground level is one atmosphere (bar), the hydrogen pressure in the tanks would be several hundred bar. Hard to see why they would leak more even if the aircraft were in a vacuum (zero bar). At 40,000 feet its about 0.1 bar outside.
By your own reckoning, that's 10x less pressure outside. I'd say that's quite a difference.
Lets make this really simple, just for you.
Pressure in tank = 700 bar (as in Toyota Mirai)
Outside pressure = 1 bar, tank pressure differential = 699 bar
Outside pressure = 0.1 bar, tank pressure differential = 699.9 bar
Percentage increase in tank pressure differential (ground level to 40,000 feet) = [(0.9/699)*100] which is ~0.13%.
Hope that helps.
Hydrogen fuelled deep ocean submarines (say a SuperTrieste) wouldn't need pressure tanks at all.
I suppose you'd have to fill them down there though.
Tricky.
Electrolysis and a long cable?
Some are working on different ideas to store Hydrogen, one is the paste mentioned which appears to be a good idea, and another is store Hydrogen on a disc which sounds odd but appears to work, instead of a car carrrying a large tank, it carries a small tank kept under pressure by a pump, discs are used to store the gas in cells which is released by laser and using the pump compresses it for the tank then to FC. the gas is produced by sewer gas and plasma then compressed into the discs which can be bought at any fuel station, if it works?
the latter is thought to be a possible to be used by Toyota (not confirmed as yet) as they appear to want several systems of power to be used in thier cars.
all interesting stuff and it will I gather be tested at some point this year
|
Also unsure how having hydrogen under extremely high pressure in aircraft travelling in a very low pressure environment (i.e. that would encourage leaks) would necessary be the ideal answer either.
The pressure at ground level is one atmosphere (bar), the hydrogen pressure in the tanks would be several hundred bar. Hard to see why they would leak more even if the aircraft were in a vacuum (zero bar). At 40,000 feet its about 0.1 bar outside.
By your own reckoning, that's 10x less pressure outside. I'd say that's quite a difference.
Lets make this really simple, just for you.
Pressure in tank = 700 bar (as in Toyota Mirai)
Outside pressure = 1 bar, tank pressure differential = 699 bar
Outside pressure = 0.1 bar, tank pressure differential = 699.9 bar
Percentage increase in tank pressure differential (ground level to 40,000 feet) = [(0.9/699)*100] which is ~0.13%.
Hope that helps.
My point was that using an extremely highly pressurised set of tanks throughout an aircraft which then would be subject to yet more stresses at high altitude from low pressure would not exactly be conducive to safety or avoid leaks, especially where the skin of the aircraft changes shape there due to significant temperature and pressure effects.
I can only imagine the catestrophic effects that a fuel leak in one tank would cause. At least with liquid fuels, the difference in pressure just meas it leaks out (assuming there's no electrical faults that would ignite the fuel), rather than does so either as a powerful jet, or perhaps all at once, causing knock-on ruptures in other tanks and possibly of the fuselage, which may well result in the loss of the aircraft.
|
My point was that using an extremely highly pressurised set of tanks throughout an aircraft which then would be subject to yet more stresses at high altitude from low pressure would not exactly be conducive to safety or avoid leaks, especially where the skin of the aircraft changes shape there due to significant temperature and pressure effects.
I can only imagine the catestrophic effects that a fuel leak in one tank would cause. At least with liquid fuels, the difference in pressure just meas it leaks out (assuming there's no electrical faults that would ignite the fuel), rather than does so either as a powerful jet, or perhaps all at once, causing knock-on ruptures in other tanks and possibly of the fuselage, which may well result in the loss of the aircraft.
And you are suggesting designers are so stupid they would not think of that?
Really?
Sorry but this is classic "objection raising for the sake of it".
|
|
Hindenberg disaster is often cited as the reason for the failure of the airship concept. H2 was seen as a major safety risk in lighter than air craft, and under high pressures required as a fuel highly explosive.
Not often appreciated is that 62 of the 97 on board actually survived - mainly as the heat and flames went up, whilst the airship slowly fell.
|
Hindenberg disaster is often cited as the reason for the failure of the airship concept. H2 was seen as a major safety risk in lighter than air craft, and under high pressures required as a fuel highly explosive.
Not often appreciated is that 62 of the 97 on board actually survived - mainly as the heat and flames went up, whilst the airship slowly fell.
You been reading my posts? I didn't think anyone did that.
|
My point was that using an extremely highly pressurised set of tanks throughout an aircraft which then would be subject to yet more stresses at high altitude from low pressure would not exactly be conducive to safety or avoid leaks, especially where the skin of the aircraft changes shape there due to significant temperature and pressure effects.
I can only imagine the catestrophic effects that a fuel leak in one tank would cause. At least with liquid fuels, the difference in pressure just meas it leaks out (assuming there's no electrical faults that would ignite the fuel), rather than does so either as a powerful jet, or perhaps all at once, causing knock-on ruptures in other tanks and possibly of the fuselage, which may well result in the loss of the aircraft.
And you are suggesting designers are so stupid they would not think of that?
Really?
Sorry but this is classic "objection raising for the sake of it".
No, it's not, because I wasn't aware of any grand plan to use hydrogen to fuel aircraft. I should point out that just because something is technically possible, doesn't make it feasible, economic or safe.
It was precisely why Toyota were suprised that it took so much time, effort and cost - but still not achieving a viable mass-market design for their hydrogen ICE car. To suddenly jump to aircraft when it hasn't even been proven (again - big difference between concept and practical use in the real world) is, to me at least, a daft step to take at this time.
|
No, it's not, because I wasn't aware of any grand plan to use hydrogen to fuel aircraft.
Yeh, thats the sort of post-reading level I.m more used to
Here you go (again).
I dunno if its grand, but its a plan, and it'd be grand to have access to the petty cash kitty.
www.airbus.com/newsroom/press-releases/en/2020/09/...l
Historical groundwork from Skunk Works in the 1950's (became the Blackbird with more conventional engines)
history.nasa.gov/SP-4404/ch8-1.htm
And if thats all too theoretical for you, here is Big Daddy
en.wikipedia.org/wiki/Delta_IV_Heavy
As an old teacher of mine used to say
""Weel, Ye ken noo""
|
My point was that using an extremely highly pressurised set of tanks throughout an aircraft which then would be subject to yet more stresses at high altitude from low pressure would not exactly be conducive to safety or avoid leaks, especially where the skin of the aircraft changes shape there due to significant temperature and pressure effects.
Regardless of whether other factors may prevent hydrogen ever being used as a fuel in aircraft, your point is engineering nonsense.
You seem incapable of understanding the obvious. Given the very high pressure inside the tank, it is subjected to a negligible additional pressure differential and hence stress when the aircraft climbs from the ground to high altitude.
Hence, there is no reason why the tank would leak more at 40.000 feet than at ground level. The rest of the hydrogen system would not be similarly stressed by the very high pressure inside the tank.
Edited by misar on 28/06/2021 at 11:21
|
|
In the Toyota Mirai how is the hydrogen stored. Is it gas under pressure or in liquid? Why is it being sold/ dispensed in weight i.e.. kilogrammes. If it is gas how can they weigh it? As mention previously it is dispensed under pressure some 300 or 700 bar. Confused!
|
Gas has mass. When you have aircon regassed, the remaining gas in the system is vacuumed out and weighed. Then the appropriate amount is added to bring it to the correct pressure. My car takes 750g of refrigerant gas.
I’ll let Toyota explain how Mirai works - mag.toyota.co.uk/toyota-mirai-faq/
Edited by mcb100 on 28/06/2021 at 13:29
|
My point was that using an extremely highly pressurised set of tanks throughout an aircraft which then would be subject to yet more stresses at high altitude from low pressure would not exactly be conducive to safety or avoid leaks, especially where the skin of the aircraft changes shape there due to significant temperature and pressure effects.
Regardless of whether other factors may prevent hydrogen ever being used as a fuel in aircraft, your point is engineering nonsense.
You seem incapable of understanding the obvious. Given the very high pressure inside the tank, it is subjected to a negligible additional pressure differential and hence stress when the aircraft climbs from the ground to high altitude.
Hence, there is no reason why the tank would leak more at 40.000 feet than at ground level. The rest of the hydrogen system would not be similarly stressed by the very high pressure inside the tank.
It's the consquences of the leak as much as the leak itself, wherever it may be. I'm sure you'd agree having one at 40,000ft is far more of an issue than taxiing at the airport.
Given the mods recent post on how we all post, can we just agree to have differing opinions on this one? :-)
Edited by Engineer Andy on 28/06/2021 at 17:39
|
|
Aircraft fuel tanks have inerting systems that are used to purge the fuel tanks of air and replacing it with pure nitrogen, preventing ignition of fuel in the tank from errant sparks due to static build-up, lightning strikes etc.
In an aircraft equipped with hydrogen tanks, I imagine a similar system would be deployed to protect the fuel systems. A leak of hydrogen into an inert atmosphere cannot ignite and should pose little risk.
Rest assured, we do think about these things :-)
|
|
|
|
|
|
|
|
