Hydrogen powered aircraft.

[planedriver]

Interesting article re: hydrogen powered aircraft.

https://www.bbc.com/future/article/20210401-the-worlds-first-commercial-hydrogen-plane.

The upside is that for those of us on limited flying budgets, we could possibly see slot meters installed, where you throw in a couple of bob to do a quick circuit or two 

[kgwilson]

A balanced and realistic article. While there are problems with production and storage, technology will address these as time goes by unless battery technology improves several thousand percent exponentially.

[facthunter]

Hydrogen as a gas is not energy dense enough. Maybe ammonia or it can be from electrolysis. Keeping the internal combustion engine is best avoided as it's always going to be lacking in reliability and efficiency. Nev

[spacesailor]

Is a Lead-Acid battery, Energy dense, l think one short circuit wil be a '  Flash in the pan '

How dense is it to stick solar on Residential roofs, with batteries for night work ?

Cheap Cheap says the government. We don't have to replace those expensive power stations.

ONE JOLT from a Battery enhanced power grid, and your toast !.

spacesailor

 

[facthunter]

Any high voltage line and you are toast. Batteries don't operate at 33,000 volts and are always DC. They go through an inverter to convert to AC and have to be "synched" to the Hertz of the grid and the same voltage as it is in that particular section.  Transformers can up or reduce the voltage for distribution to users or cover larger distances.    Nev

[spacesailor]

BUT

At the residence with solar batteris, your DC amps will kill.

Normal houses don,t use 33,000 volts, at the  most we use 440 v three phase..

spacesailor

[facthunter]

VOLTS are needed as well as amps. 240 is near the worst voltage to use in households. Many places use 110. My solar open circuit voltage as about 400 which is high enough to overcome your body's resistance and would be dangerous if you were cleaning the panels etc.  Nerve conductivity tests are done at 1000's of volts but the amps are low enough to not harm you. A Magneto often puts out about 28,000 volts but has never killed anyone as far as I know. It certainly makes your muscles twitch. Nev

[kgwilson]

Volts is pressure, amps is current or flow and ohms is resistance. You can have thousands of volts but almost no amps as in a static electricity discharge from an acrylic T shirt on a very dry day you will see the sparks sometimes and hear the crackles but there is no danger at all as there is no current.. A battery holds the charge and a direct discharge from positive to negative with a copper wire will cause the flow of amps to quickly overwhelm the amperage capacity of the wire and heat it until it melts within seconds. If electrical resistance is placed in the middle of the wire like a light bulb it will just slowly consume the charge.

 

We use nominally 230 volts (220-240) in Australia. The longer the wire the fewer volts there will be at the end. this is why there are transformers all around the neighbourhood as the supply comes in a very high voltage and it is reduced for the consumer. If it was reduced to 110 volts as in parts of the US to get the same current you need thicker wire. It is still just as dangerous.

[onetrack]

There is a far greater likelihood of a battery breakthrough with regard to increased energy density, than there ever is of hydrogen power becoming an economic reality.

 

I know a group of Japanese car manufacturers (Toyota included) are intent on creating a range of hydrogen-powered vehicles - but I personally think they're trying to fly a lead balloon.

 

Hydrogen has way too many inherent problems with regards to handling, transport and storage. And at the end of the day, it still has poor energy density compared to petrol or diesel.

 

A hydrogen leak is more dangerous than any other gas leak, hydrogen has the highest flammability range, and the lowest required ignition energy of any fuel.

[Bruce Tuncks]

I reckon the future might have synthetic liquid fuels. For example, methanol ( CH3OH ) is what model planes used to use before being ousted by Li-Po batteries. If you have hydrogen, I think it relatively easy to make methane (CH4) and then methanol.

I dunno if I agree with you kgwilson. Electric battery planes are cost-effective right now for some applications like training and gliders. A tenfold improvement would see battery power good for most of us who fly for an hour or two most of the time. And they sure displaced methanol model plane engines just on convenience grounds, with no incentives at all. I changed because the model plane stays clean and oil-free,  and going model flying is much simpler.

I do have several methanol models which are unused these days.

[Bruce Tuncks]

Correction...  it is not that cheap at the moment to make methanol from hydrogen and CO2 but there are research places trying catalysts etc and hopefully this will change.

[spacesailor]

I too have model planes witn IC motors, it,s illegal to fly them around here, those Beaurocrates say Only electric.

spacesailor

[facthunter]

KG 110 volts is not as dangerous. That is the main reason it's used where it is used. The body's internal resistance  affects what current will go through it at any specific voltage.  Nev

[Bruce Tuncks]

Quite right Nev. As a kid, I  had 240 volt shocks but never a bad one. For example, if you are touching the active wire (240 times root2 max volts ) but your hand is dry and you have sneakers on ( rubber soles) then you have a very high resistance path for the volts and while you will feel the jolt, it will not hurt you.

On the other hand, if you were touching a ground with the other hand and  your hands were wet, at least a thousand times more current will flow through you.

Our 240 volt system is in my opinion better than the american 110 volts as our losses are less. But yes it can be more lethal. 

Play with an ohm-meter and you will see what I mean. The skin, if dry, is the major point of resistance. Inside, we are exactly as saline as the ocean from whence our ancestors came, and this is very little resistance. 

 

[facthunter]

I've lost a few friends who were plumbers working under houses. I used to build my own 240V ac rectifiers and have had 240 through me at least 4 times with no ill effects. I don't consume any salt extra to what I get from vegetables and I attribute that to the outcome. My sweat doesn't taste saline either..  Many earthing  setups use the water pipes when they were copper or GAL and sometimes your tongue will tingle when you drink from it. The tongue can detect very small voltages. Nev

[octave]

3 hours ago, onetrack said:

I know a group of Japanese car manufacturers (Toyota included) are intent on creating a range of hydrogen-powered vehicles - but I personally think they're trying to fly a lead balloon.

There are numerous hydrogen fuel cell cars commercially available right now.

Cars commercially available for sale or leasing.

• 2008-2015 Honda FCX Clarity^[2]
• 2013–2017 Hyundai Tucson/ix35 Fuel Cell^[3]
• 2015-2020 Toyota Mirai
• 2016 - Roewe 950 fuel cell (plug-in hybrid fuel cell)^[4][5]
• 2016 - Honda Clarity Fuel Cell^[6][7]
• 2018 - Hyundai Nexo
• 2020 - Toyota Mirai II

The main problem at this point is the lack of places to refuel.

 

[facthunter]

Hydrogen The most elemental of the elements will leak more than any other element. It can't easily be liquified and is not an energy dense fuel. It's OXIDE, WATER is a large part of US. Nev

[kgwilson]

110V is half as dangerous at the same amperage level and because volts is pressure the current gets depleted by resistance so yes it is less dangerous but it only takes 50 milli-amps at 110 volts to stop the heart. Over 90% of all electrocutions in the USA happen in residential homes and are from the 110 volt system as people truly believe it is the voltage that causes electrocution and consider 110V safe.

[octave]

This is an interesting look into the pros and cons of hydrogen for vehicles

 

The Truth about Hydrogen

 

 

 

[facthunter]

The amperage is dependant on the bodies resistance whatever the supply is CAPABLE of. I cop 28,000 volts regularly doing magneto's and I've never heard of anyone being killed  (or affected) by one of those as it's relatively low amps at the source.. I wouldn't recommend anything like that with a pacemaker of course. The earth return circuit breakers have saved multiple lives here  Cord electric mowers used to regularly kill a few also. Nev

[turboplanner]

4 hours ago, Bruce Tuncks said:

Correction...  it is not that cheap at the moment to make methanol from hydrogen and CO2 but there are research places trying catalysts etc and hopefully this will change.

Methanol has been mandatory in some forms of race cars for 40 years or more. because of its safer flash point than petrol.

Racing fuel is usually 95% methanol and 5% acetone for smoother burning.

It's not that expensive, and readily available in 20 litre or 200 Litre drums.

It's characteristics in an ICE are: it burns slower than petrol,  runs cooler than petrol, puts out the same amount of power, if not a little more, but requires twice the volume to get the same result.

 

If you translate that into a road car or aircraft, the fuel bill with be about 2.5 times petrol and the fuel tank has to be twice the size, so twice the weight of fuel.

 

So you wouldn't be looking at using Methanol to power aircraft or cars.

 

If you assess any of these alternative fuels in the way I just did, you'll find the reason we still use petrol or diesel.

 

An ICE burning hydrogen has to store liquid hydrigen, so requires a huge tank. Compressed Natural Gas (CNG) died for much the same reason - a massive storage tak which operated at about 2000 psi, so had to be made as strong as an oxy cylinder.

 

A fuel cell power plant which separates hydrogen and oxygen producing electricity which powers an electric motor worked successfully in Perth's MTT Buses on an extended trialle, but was killed by its cost - three times that of a diesel bus.

 

Most of these exotics are coming to light as a result of relentless pressure to reduce CO2 emissions to stop global warming. The reason Hydrogen is coming to the surface now is that people have realised that electric cars might have zero tailpipe emissions but they have to be charged, and even a 50% market share of EVs would require Australia to double the number of power plants supplying the grid, so a big increase in CO2, unless we switched to nuclear.

 

[onetrack]

Quote

Compressed Natural Gas (CNG) died for much the same reason 

 

No, CNG hasn't died - not here in on the left Coast, anyway. The Public Transit Authority in W.A. operates 1138 diesel-powered buses and 512 CNG buses, which are diesel buses converted to CNG.

The CNG buses are very acceptable to the PTA, but the life-cycle cost of the CNG buses is affected by big variations in the price of diesel.

When diesel prices are high, the CNG buses are in front. When the cost of diesel falls substantially (as it did in 2020), the CNG buses are at a disadvantage.

The CNG buses in the first decade of this century had a sizeable advantage in reduced emissions, but the "clean diesel" (low sulphur) improvement brought about by Govt regulation means the current diesel emissions, in combination with Euro 5 technology and exhaust treatments, is matching the low emissions levels of CNG in the buses.

W.A. has the advantage of a large supply of relatively cheap Natural Gas, and the only major additional cost is in compressing it.

The PTA has the advantage of only needing refuelling infrastructure at 2 places, in the Perth region, and Perth is on the route of the huge Dampier-Bunbury natural gas pipeline from the N.W. Shelf gas deposits of W.A.

 

Edited April 11, 2021 by onetrack

[turboplanner]

There are still some isolated operations in the east, but the main CNG action was  pretty much over by 2010. The attraction in Victoria was the ESSO BHP oilfields off the coast in Bass Strait where we were told there were hundreds of years of supply of natural gas. We are now being told there is none left and are about to buy subsidised gas from China, so someone screwed up somewhere.

 

Route Buses were the best hope for CNG because there was plenty of room for the big tanks, but route buses are the most power hungry application of all buses and coaches, so the 10% or so power loss wouldn't have helped timetables.

 

Benders in Geelong operated a fleet of CNG buses in that city, but they were all gone by about 2005.

 

Isuzu brought out trial trucks in both compression ignition and specific CNG spark ignition configurations, but didn't go ahead with production trucks.

 

As you mention, the emission advantage CNG had was eaten up by cleaner diesel fuel, and over the next decade or two the automotive industry looks like progressively introducing compression ignition petrol engines, so we'll probably see diesel drop as a front line fuel source.

[octave]

30 minutes ago, turboplanner said:

There are still some isolated operations in the east, but the main CNG action was  pretty much over by 2010. The attraction in Victoria was the ESSO BHP oilfields off the coast in Bass Strait where we were told there were hundreds of years of supply of natural gas. We are now being told there is none left and are about to buy subsidised gas from China, so someone screwed up somewhere.

Aren't we talking about hydrogen fuel cells rather than CNG?

[spacesailor]

Another  OXYMORON

Government reguations to clean diesel engines !.

You need power, so accelerate, Then the exhaust Gas reticulate.  System puts more exhaust gas Into the engine lowering power, so to compensate,  More acceration required, gives more EGR, causing lower power output, untill your ' flatout '

Pumping lots of smoke, just to compensate for Bureaucracy.

EGR ' BLANKING PLATES ' available from OEM . Tells us something is wrong if they provide  the FIX !.

spacesailor