Page 4 of 5 FirstFirst ... 2345 LastLast
Results 91 to 120 of 136

Thread: Hydrogen engines

  1. #91
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,118
    Quote Originally Posted by profloater View Post
    Gravity has always been useful to store energy, eg falling weight clocks, but a big falling weight can bereplaced with a small battery.
    Or vice versa.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  2. #92
    Join Date
    Feb 2005
    Posts
    11,594
    Quote Originally Posted by profloater View Post
    Hydrogen might be useful in airplanes. There is talk of storing hydrogen in high surface area solid foams. Super high pressure tanks are a challenge but super insulated cryogenics could make hydrogen feasible. The best plan might be hydrogen airships with technology to scrub out oxygen. It has been done! It is high time to reconsider because Helium is scarce and expensive.
    Agreed. Airships with ion wind bits sticking out--an air-warp nacelle--and a a dirigible is just about a rectenna for beamed power to boot.

  3. #93
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Quote Originally Posted by publiusr View Post
    Agreed. Airships with ion wind bits sticking out--an air-warp nacelle--and a a dirigible is just about a rectenna for beamed power to boot.
    That makes sense, a multi new technology class of vehicles, capable of vertical take off, hover, faster than boats, capable of flying over land or sea with long endurance. And no CO2. Solar power can be added too. I would add internal fibres like double wall fabrics, to reduce the cross section and make a faster shape, capable I would think of 300 mph. While slower than today’s planes, it can have huge lift capability at lower cost. Docking in high wind remains a challenge.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  4. #94
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,118
    Quote Originally Posted by profloater View Post
    Docking in high wind remains a challenge.
    That's easy! Just dock indoors.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  5. #95
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Quote Originally Posted by Noclevername View Post
    That's easy! Just dock indoors.
    Ah I should have thought of that! I am wondering what sort of scale effects apply to a very large airship with shape changing capability
    , the shape responding to a specially inflated outer skin which has both gas exchange and flexing solar panels as well as a large volume of hydrogen. I like a long (Baguette) shape for flight, curled into a ring for landings or hovering. That could form a sky train of links like sausages, but maybe I will have to wait to see that.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  6. #96
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    H2the Robinson , channeled while floating:

    An “Hysky “ carriage is a cylinder 20m in diameter and 200m long. Filled Hydrogen it has a gross lift of about 60 tons. The cylinder walls form a rolling diaphragm so that when the rigid disc ends are winched together the volume and lift are halved , making the net carriage heavier than air. This is for docking and landing.
    The gondola beneath the cylinder might be 60 m long with accommodation for 200 passengers.
    The disc ends house thrusters powered by hydrogen engines.
    Any number of these carriages can link to form a train with reduced form drag.
    Drag of course depends on velocity squared so there is a complete trade off since this is a buoyant craft. By using the variable geometry it can hover or fly at any altitude up to say 4000 m where atmospheric pressure is halved. The payload must be reduced for high flying. Most people can tolerate that height without pressurising the gondola.
    1000 HP thrusters will consume about 50 kg per hour of Hydrogen, 20 hours per ton, maybe, so it might cross the Atlantic. (More work required there, bigger scale might be required.)
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  7. #97
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,118
    Quote Originally Posted by profloater View Post
    Ah I should have thought of that! I am wondering what sort of scale effects apply to a very large airship with shape changing capability
    , the shape responding to a specially inflated outer skin which has both gas exchange and flexing solar panels as well as a large volume of hydrogen. I like a long (Baguette) shape for flight, curled into a ring for landings or hovering. That could form a sky train of links like sausages, but maybe I will have to wait to see that.
    It will probably take a lot of wind tunnel and maybe full scale prototype tests to figure out if such a complicated design should fly! Maybe the landing structures need wind tunnel testing too-- maybe tall vanes to direct the wind around incoming airship? I also think a layer of inert gas between the main cells and the outer skin, to lessen the likelihood of a hydrogen leak.

    Back to engines; Would the lift hydrogen also serve to power the motors? If so, you'd need to carry a lot of ballast to dump as the lift decreases.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  8. #98
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Quote Originally Posted by Noclevername View Post
    It will probably take a lot of wind tunnel and maybe full scale prototype tests to figure out if such a complicated design should fly! Maybe the landing structures need wind tunnel testing too-- maybe tall vanes to direct the wind around incoming airship? I also think a layer of inert gas between the main cells and the outer skin, to lessen the likelihood of a hydrogen leak.

    Back to engines; Would the lift hydrogen also serve to power the motors? If so, you'd need to carry a lot of ballast to dump as the lift decreases.
    I addressed some of these with my rather whimsical post above. Hydrogen dirigibles did ply the Atlantic before the Hindenburg disaster, and such a disaster should be preventable. Using the hydrogen as fuel means excess hydrogen but I think that can be added to the big envelope. Some of the current or near to production helium dirigibles show many attractive features, the hydrogen alternative needs to overcome a bad reputation.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  9. #99
    Join Date
    Jan 2010
    Location
    Wisconsin USA
    Posts
    2,910
    Quote Originally Posted by profloater View Post
    I addressed some of these with my rather whimsical post above. Hydrogen dirigibles did ply the Atlantic before the Hindenburg disaster, and such a disaster should be preventable. Using the hydrogen as fuel means excess hydrogen but I think that can be added to the big envelope. Some of the current or near to production helium dirigibles show many attractive features, the hydrogen alternative needs to overcome a bad reputation.
    I think it would be too easy for an amateur to use a dirigible as a terrorism target. I don't know how anyone ever gets around that. If anyone ever worked in manufacturing or healthcare it also seems like there isn't a good work around to prevent errors when working with large volumes of hydrogen in one place without causing a disaster due to error or incompetence. I could be horribly wrong on this.
    There must be multiple good reasons that almost every car company has abandoned hydrogen fuel cells
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

  10. #100
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,118
    Quote Originally Posted by Copernicus View Post
    I think it would be too easy for an amateur to use a dirigible as a terrorism target. I don't know how anyone ever gets around that. If anyone ever worked in manufacturing or healthcare it also seems like there isn't a good work around to prevent errors when working with large volumes of hydrogen in one place without causing a disaster due to error or incompetence. I could be horribly wrong on this.
    The same is true of fuel refineries and gasoline tankers. Yet they are ubiquitous.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  11. #101
    Join Date
    Jan 2010
    Location
    Wisconsin USA
    Posts
    2,910
    Quote Originally Posted by Noclevername View Post
    The same is true of fuel refineries and gasoline tankers. Yet they are ubiquitous.
    I've thought of that too. And I could be wrong, but hydrogen just seems so much harder to contain, and so much more explosive. Part of the reason it is rarely found pure in nature.
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

  12. #102
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Quote Originally Posted by Copernicus View Post
    I think it would be too easy for an amateur to use a dirigible as a terrorism target. I don't know how anyone ever gets around that. If anyone ever worked in manufacturing or healthcare it also seems like there isn't a good work around to prevent errors when working with large volumes of hydrogen in one place without causing a disaster due to error or incompetence. I could be horribly wrong on this.
    There must be multiple good reasons that almost every car company has abandoned hydrogen fuel cells
    Yes I can see that could be right. I suspect lithium batteries seem better but larger hydrogen fuel cells are still commercial.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  13. #103
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,118
    Method of splitting water without high energy cracking: https://www.titech.ac.jp/english/news/2019/045462.html
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  14. #104
    Join Date
    Jan 2010
    Location
    Wisconsin USA
    Posts
    2,910
    Quote Originally Posted by Noclevername View Post
    Method of splitting water without high energy cracking: https://www.titech.ac.jp/english/news/2019/045462.html
    That would be a cool project to work on.
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

  15. #105
    Join Date
    Jun 2007
    Posts
    5,772
    Quote Originally Posted by Noclevername View Post
    Method of splitting water without high energy cracking: https://www.titech.ac.jp/english/news/2019/045462.html
    The process that generates sunlight is pretty high energy.

    I see a lot of researchers trying to use photochemical techniques to generate hydrogen using sunlight, but I've never seen a good rationale for why this would be desirable. It seems unlikely to be as efficient as photovoltaics and high temperature electrolysis, and all the plumbing involved in running high-purity water out to a field of solar collectors (including keeping it liquid in cold weather) and inevitably leaky hydrogen lines going back to a compression/storage system does not seem anywhere near as practical as a field of photovoltaics and a centralized electrolysis setup.

  16. #106
    Join Date
    Jan 2010
    Location
    Wisconsin USA
    Posts
    2,910
    Quote Originally Posted by cjameshuff View Post
    The process that generates sunlight is pretty high energy.

    I see a lot of researchers trying to use photochemical techniques to generate hydrogen using sunlight, but I've never seen a good rationale for why this would be desirable. It seems unlikely to be as efficient as photovoltaics and high temperature electrolysis, and all the plumbing involved in running high-purity water out to a field of solar collectors (including keeping it liquid in cold weather) and inevitably leaky hydrogen lines going back to a compression/storage system does not seem anywhere near as practical as a field of photovoltaics and a centralized electrolysis setup.
    Your argument seems very logical.
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

  17. #107
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Quote Originally Posted by cjameshuff View Post
    The process that generates sunlight is pretty high energy.

    I see a lot of researchers trying to use photochemical techniques to generate hydrogen using sunlight, but I've never seen a good rationale for why this would be desirable. It seems unlikely to be as efficient as photovoltaics and high temperature electrolysis, and all the plumbing involved in running high-purity water out to a field of solar collectors (including keeping it liquid in cold weather) and inevitably leaky hydrogen lines going back to a compression/storage system does not seem anywhere near as practical as a field of photovoltaics and a centralized electrolysis setup.
    I think large systems like ships will find hydrogen fuel cells better than batteries. But of course the hydrogen will have to be stored and moved around.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  18. #108
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    37,118
    Quote Originally Posted by cjameshuff View Post
    The process that generates sunlight is pretty high energy.
    Well, yeah, but we don't have to pay for it. Also, it uses hydrogen!
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  19. #109
    Join Date
    Jun 2007
    Posts
    5,772
    Quote Originally Posted by profloater View Post
    I think large systems like ships will find hydrogen fuel cells better than batteries. But of course the hydrogen will have to be stored and moved around.
    I'm not seeing the connection between large ships and "hydrogen from sunlight" schemes.

  20. #110
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Quote Originally Posted by cjameshuff View Post
    I'm not seeing the connection between large ships and "hydrogen from sunlight" schemes.
    Well if ships use hydrogen fuel cells, they would need land based H generation and to be properly green that needs renewable sources. Wind and solar farming sources are increasing now that the cost benefit as well as the environmental factor favours them. Even in the UK i see many whole fields changing to PV solar over crop growing. Many countries with more sunshine could become energy exporters. Hydrogen is one way to transport the energy to ships.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  21. #111
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    https://www.maritime-executive.com/a...ship-scheduled
    Like this. This link announces hydrogen fuel cell ships being built now.
    Last edited by profloater; 2019-Oct-27 at 11:42 AM. Reason: Add explanation of link
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  22. #112
    Join Date
    Jun 2007
    Posts
    5,772
    Quote Originally Posted by profloater View Post
    Well if ships use hydrogen fuel cells, they would need land based H generation and to be properly green that needs renewable sources. Wind and solar farming sources are increasing now that the cost benefit as well as the environmental factor favours them. Even in the UK i see many whole fields changing to PV solar over crop growing. Many countries with more sunshine could become energy exporters. Hydrogen is one way to transport the energy to ships.
    The production doesn't and can't take place anywhere near the ships. The ships don't care where the hydrogen comes from. The existence of the ships changes absolutely nothing about the plumbing, complexity, and climate issues. Those fields would still be covered in collectors, they'd just be connected with plumbing and tanks instead of wiring, and they'd only be able to provide hydrogen instead of covering other electrical power needs as well.

    How, exactly, do hydrogen fuel cell ships make photochemical hydrogen production desirable?

  23. #113
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Quote Originally Posted by cjameshuff View Post
    The production doesn't and can't take place anywhere near the ships. The ships don't care where the hydrogen comes from. The existence of the ships changes absolutely nothing about the plumbing, complexity, and climate issues. Those fields would still be covered in collectors, they'd just be connected with plumbing and tanks instead of wiring, and they'd only be able to provide hydrogen instead of covering other electrical power needs as well.

    How, exactly, do hydrogen fuel cell ships make photochemical hydrogen production desirable?
    I do not understand your question. The ships need land based hydrogen production. Hydrogen becomes a commercial fuel intermediary for renewable, ie solar powered, energy. Overall, that is desirable.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  24. #114
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Quote Originally Posted by cjameshuff View Post
    The production doesn't and can't take place anywhere near the ships. The ships don't care where the hydrogen comes from. The existence of the ships changes absolutely nothing about the plumbing, complexity, and climate issues. Those fields would still be covered in collectors, they'd just be connected with plumbing and tanks instead of wiring, and they'd only be able to provide hydrogen instead of covering other electrical power needs as well.

    How, exactly, do hydrogen fuel cell ships make photochemical hydrogen production desirable?
    Oh do you mean photosynthetic rather than PV? That is for developers to check out. I agree that chemistry supports CO2 capture in the former. My point was about hydrogen engines in general. Ships can use biofuels but some will choose hydrogen.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  25. #115
    Join Date
    Jun 2007
    Posts
    5,772
    Quote Originally Posted by profloater View Post
    Oh do you mean photosynthetic rather than PV? That is for developers to check out. I agree that chemistry supports CO2 capture in the former. My point was about hydrogen engines in general. Ships can use biofuels but some will choose hydrogen.
    No, I do not. Go re-read what you quoted in post 107. Your response to it makes no sense.

  26. #116
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Quote Originally Posted by cjameshuff View Post
    No, I do not. Go re-read what you quoted in post 107. Your response to it makes no sense.
    In 107 I was in favour of hydrogen without actively disagreeing with your post which is true at present. The demand for hydrogen will increase so there is hope for non pv processes, while I agree that chemical solar routes favour cO2 capture as hydrocarbons. Researchers do not necessarily produce commercial products but they push the boundaries of the possible. I am sorry it made no sense to you, I was replying within the context of the OP as to why hydrogen engines are not yet more common, I think they will be part of the future.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  27. #117
    Join Date
    Jun 2007
    Posts
    5,772
    Quote Originally Posted by profloater View Post
    In 107 I was in favour of hydrogen without actively disagreeing with your post which is true at present. The demand for hydrogen will increase so there is hope for non pv processes, while I agree that chemical solar routes favour cO2 capture as hydrocarbons. Researchers do not necessarily produce commercial products but they push the boundaries of the possible. I am sorry it made no sense to you, I was replying within the context of the OP as to why hydrogen engines are not yet more common, I think they will be part of the future.
    ...
    How would any level of demand make photochemical approaches favorable? Why would anyone ever install a field of solar arrays composed of electrochemical cells covered with special catalysts and plumbing for 3+ different fluids, with both the chemistry and the plumbing being sensitive to low temperatures, producing fuels that have to be piped to storage, compressed, and at some point transported to a buyer, when they can just use photovoltaics?

    Complicating things by feeding CO2 to the panels as well does not improve matters. Solar photochemical approaches are just a bad idea.

  28. #118
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Quote Originally Posted by cjameshuff View Post
    ...
    How would any level of demand make photochemical approaches favorable? Why would anyone ever install a field of solar arrays composed of electrochemical cells covered with special catalysts and plumbing for 3+ different fluids, with both the chemistry and the plumbing being sensitive to low temperatures, producing fuels that have to be piped to storage, compressed, and at some point transported to a buyer, when they can just use photovoltaics?

    Complicating things by feeding CO2 to the panels as well does not improve matters. Solar photochemical approaches are just a bad idea.
    OK I get that, I will mention it to my trees.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  29. #119
    Join Date
    Jun 2007
    Posts
    5,772
    Quote Originally Posted by profloater View Post
    OK I get that, I will mention it to my trees.
    The ones that are currently shedding their photosynthetic surfaces as they go into dormancy for the winter?
    And which operate at only a few percent efficiency when they do have leaves, much of that being used for their own growth?
    And which don't actually produce any hydrogen at all?

  30. #120
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    8,718
    Photosynthesis might be a red leaved herring, indeed, but the use of hydrogen in engines remains interesting. I was focussed on future H ships as a prime example. I never meant to imply photosynthesis would be a route. That belongs in a carbon capture thread.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •