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  • Need Help With Pneumatic Battery

    I am trying to conceptualize a proof of concept for a pneumatic battery. The idea starts with the realization that chemical batteries are temporary. They have a very limited lifespan, do not hold substantial amounts of power, are sometimes explosive, and they contain toxic materials.

    The basic premise for a pneumatic battery is using a high torque, high RPM pneumatic motor and re-purposed ex-gasoline or ex-diesel generator to produce 12v, 120v, and 220v power. Solar panels would drive a compressor to pressurize air to 3000 PSI in re-purposed oxygen tanks. A vacuum tank could boost motor efficiency and reduce internal condensation. A large volume tank could increase the compressor efficiency and system capacity. This system could be used to store energy as pressurized air, and released that energy as electricity as needed. Compressing air would generate heat, and decompressing it would create cool, providing for additional pressure through thermal expansion and reduced temperatures to reduce friction heat.

    My proof of concept should be about 50 gallon cooler sized, portable with wheels for camping. That large cooler sized model would contain the compressor, high pressure tank, and generator, with a lid-top solar panel. It would be able to attach to two larger external tanks One for the vacuum and one as the low pressure high volume tank. Those tanks could be buried for permanent locations or put on a trailer in in a shipping container for mobile applications. Both provide more space for more panels for more compression, and a shipping container could add to climate controlled to increase thermal impacts..

    I have joined this group to hear your views on such a system. I have created a post that outlines it here:
    https://www.facebook.com/groups/Boga...5677223120330/

    Here is a diagram that describes the system. Hope you can decipher it!212264651_10158134406832231_8679330318114394725_n.jpg?_nc_cat=100&ccb=1-3&_nc_sid=825194&_nc_ohc=_zpIK3Ltq-EAX_Q-d4F&tn=LA4ekXumuy3Aqpsy&_nc_ht=scontent-ort2-2.xx&tp=6&oh=87a04a83c6ba4d77aeb1c20457ec35c5&oe=60EC58DE.jpg

    Thank you in advance for any respectful responses,
    -hip
    Attached Files
    Last edited by happy_hipster; 07-08-2021, 10:08 AM.

  • #2
    What engineering, design or practical operating experience do you gave with high pressure gas or vacuum systems ?

    Comment


    • #3
      I do not see any 120V or 240V connections to your diagram. What is the nature
      of the Pneumatic Generator? What is the estimated efficiency of the energy storage?
      Bruce Roe

      Comment


      • #4
        In the diagram, the 12v, 120v and 240v connections would come from the Generator, labeled 8. I was hoping to use a 6000W gasoline generator with the gas .motor part removed and replaced with a high RPM high torque pneumatic motor. I do not know how to estimate efficiency of the energy source without the specs on the imagined solar panels, pneumatic motor, generator, or compressor.


        As far my engineering experience, I did go to college for several years for Electrical Engineering before entering the Navy to be a nuke. Now I am a roofer, and a carpenter and have used both air powered tools and a generator. Bah hahahhahahahahhaha
        Last edited by happy_hipster; 07-08-2021, 09:45 PM.

        Comment


        • #5
          First thing I would do, is note the piston cylinder ring leakage, that loss may be a deal breaker.
          Most air storage systems use large salt caves or abandoned mines. Even something the scale of a 500gal propane tank, is not going to store much in terms of watt hours
          Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
          || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
          || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

          solar: http://tinyurl.com/LMR-Solar
          gen: http://tinyurl.com/LMR-Lister

          Comment


          • #6
            If you want to do it as mental exercise, have at it, just dont spend any money on it as its far better to invest it in important stuff like beer . The problem you have is the efficiency of the compressor and generator. They both are very poor so your wire to wire efficiency is impacted by both. CAES is generally only viable when the scale is very large (and the incentives high)

            Keep in mind compressing air creates heat and expanding it cools. This heating and cooling is part of the cycle efficiency so unless you are recovering it that is power leaving the system that is not being used to generate power.

            The likelihood is the compressor and expander would be turbine based. There will be rotating parts near fixed parts and there will need to be clearances between the two. This clearance is potential lost energy recovery. As the turbine gets smaller that clearance space as a percentage of the rotor area increases so the bigger the better which is one reason why CAES systems tend to be quite large.

            Ultimately you want density of the working fluid as you are converting stored energy into kinetic energy and it ultimately comes down to M*V squared. Air doesnt have a lot of M (mass) Hydraulics are great for that but they are not compressible. If an accumulator is used, the bladder has air on one side being heated and cooled so the heating and cooling effects still are in the loop. Ideally you pump up into reservoir at higher elevation and skip the accumulator and then it becomes a pumped storage system. No heating and cooling to speak of.

            Comment


            • #7
              Mike, now you are getting somewhere! Until a pneumatic motor can provide the torque and RPM efficiently, this system may not be the most efficient from the watt hours standpoint. But can a more effective and efficient method of providing that drive be found, if the system proves to work? Some sort of turbine?

              Another thing to consider is that systems without a grid tie pretty much sit dormant once all the batteries are charged, Finding a way to capture some of that dormant potential makes the entire system more efficient, regardless of the component efficiency. You may be right, from the watt hour standpoint, it may be a deal breaker, but what about the watt/dollar over time side? If batteries are disposable, and this is permanent, then isn't that a deal breaker for batteries?

              That is the deal breaker for me. Im not going to put thousands into batteries every few years to power a home.

              I hear what you are saying about propane tanks, but also have seen oxygen tanks in the 500gal range for hospitals. This would increase the capacity up to 3000 PSI to 500 gallons and up. Im sure you cant do THAT in a salt mine. Increasing the PSI capacity also increases the shear volume exponentially, but this also hits efficiency in the are of loss to compressors.

              I still think that the loss due to panels being idle and batteries dying is something that makes it practical and useable. How long does one need an emergency generator in the case of a power outage, and could this supplement the solar power an off grid Air B n B if it is only rented for a day once a week, or a week once a month?

              Comment


              • #8
                What I invested in is two solar panels. They are just expensive glass and metal at this point because I am not investing into disposable batteries. I think the efficiency of THAT system is far lower then one with a permanent battery. A permanent battery in the form of compressed air should work, I know they have created pneumatic vehicles. As for thermal loss and gain, both are very usable products, as is condensed water from humidity.

                It is a very healthy mental exercise, and Im glad you have contributed a little in that way. The idea is not to tell me how it will never work, but to imagine how it could. I like that. Compressing Air until it turns into a liquid is a goal for a system such as this. Then it would make more mechanical means of generation work in deep water, where liquified air would lose all buoyancy, could be used as a weight, decompressed on the sea floor to drive a pneumatic generator, and raise a float to pull an elevator up to create more power, completing a circle of power that starts with the sun.

                An oceanic elevator that generates power with gravity on the way down, generates power decompressing the air, and creates energy with buoyancy up. This all starts with creating the pneumatic generator, folks.

                And no, I dont smoke weed.
                Last edited by happy_hipster; 07-12-2021, 05:05 PM.

                Comment


                • #9
                  https://jestec.taylors.edu.my/Vol%20...%20496-515.pdf 1. Introduction Liquid air is air liquefied at -196°C at atmospheric pressure. Traditionally, air is separated to its constituents and the constituents such as oxygen and nitrogen are liquefied for industrial purposes, as well as storage and transport. However, the liquefaction of air, without the separation process; is being studied recently for its energy storage capabilities. Liquefying air would convert electrical energy to cold energy, stored and transported, if required; and then the energy can be extracted by expanding the air. This would convert the cold energy stored to kinetic energy to move turbines and generate electricity.

                  Comment


                  • #10
                    Essentially, "compression" would not only be mechanical, but also THERMAL, using the suns energy to not only drive a piston but to chill the gas to liquification. The heat being removed would be applied to decompression, so that the gas would expand at a high rate to drive the motor (turbine or otherwise) for the generator. The turbine would not vent the air like traditional pneumatic motors, but recycle it back to the chillers and compressors, to maintain a closed system.

                    Comment


                    • #11
                      Originally posted by happy_hipster View Post
                      What I invested in is two solar panels. They are just expensive glass and metal at this point because I am not investing into disposable batteries. I think the efficiency of THAT system is far lower then one with a permanent battery. A permanent battery in the form of compressed air should work, I know they have created pneumatic vehicles. As for thermal loss and gain, both are very usable products, as is condensed water from humidity.

                      It is a very healthy mental exercise, and Im glad you have contributed a little in that way. The idea is not to tell me how it will never work, but to imagine how it could. I like that. Compressing Air until it turns into a liquid is a goal for a system such as this. Then it would make more mechanical means of generation work in deep water, where liquified air would lose all buoyancy, could be used as a weight, decompressed on the sea floor to drive a pneumatic generator, and raise a float to pull an elevator up to create more power, completing a circle of power that starts with the sun.

                      An oceanic elevator that generates power with gravity on the way down, generates power decompressing the air, and creates energy with buoyancy up. This all starts with creating the pneumatic generator, folks.

                      And no, I dont smoke weed.
                      I'm with Peakbagger on this one.

                      Aside from that, I believe I'm somewhat knowledgeable about the types of systems you seem to be pushing, and from what I think I might know, that type of stuff is generally impractical from an efficiency and operating standpoint.

                      Nice for science projects and to demonstrate scientific and engineering principles but that's about as far as it goes with little practical application except for conmen and the "you could just do this and the world would be a better place" crowd. It'll all work in theory. Not so much in reality.

                      Comment


                      • #12
                        I generally regard views like this to be put in the category of "If people could fly, we woulda dun it already" Efficiency is something that comes with R&D, and so do breakthroughs. I think ideas like this dont get off the ground because they would be a solution to an expensive problem. The problem is not the efficiency of the capture of power, in this case, it is in using expensive, explosive, toxic DISPOSABLE batteries.

                        Replacing thousands of dollars worth of batteries every 5 to 15 years does not sound very efficient. The reality is that very practical and efficient cars were mothballed for decades in order to continue profiting off of gas guzzlers, and it is only now they are being re-introduced because, well, they have to.

                        It really seems that there is more feedback about why it is absolutely infeasible to make an alternative to chemical batteries, and little to nothing about how we could be smart enough to make it work. Maybe you are right, maybe we are all too stupid to make an efficient pneumatic battery. Maybe no one has the knowledge or training to even imagine it. I dunno.

                        I hear Einstein created the concept of a three gas system for a refrigerator that worked without pumps, we just have not figured out how to do it yet, or dont WANT to because a permanent sealed refrigeration unit without moving parts is not disposable, and therefore not profitable.

                        Comment


                        • #13
                          Originally posted by happy_hipster View Post
                          In the diagram, the 12v, 120v and 240v connections would come from the Generator, labeled 8. I was hoping to use a 6000W gasoline generator with the gas .motor part removed and replaced with a high RPM high torque pneumatic motor. I do not know how to estimate efficiency of the energy source without the specs on the imagined solar panels, pneumatic motor, generator, or compressor.
                          On what I know your idea is not an option. If you think something will work then do some research.

                          Look up Bauer dive compressors, they are used to fill scuba tanks to 3000psi. Look up the capacity of scuba tanks and you will have the data to calculate how much energy is required to capture x amount of air compressed to 3000psi.


                          Look up air motors and you will get cfm required to run them. If you want to generate 6000w then you will need an air motor that can produce more than 6000w of power.


                          So you will have the cfm of air at a given psi required for your air motor to run. Then you can calculate the energy required to make that air and the size tank required to store enough to run your motor for the time required.

                          Comment


                          • #14
                            You probably missed out on thermodynamics unless you have an engineering background and generally only mechanical engineers get into slightly more advanced thermodynamics. The first law is handy for basic calculations but it assumes reversibility. These are physical laws not political ones, no loopholes. First law math says you may pull it off, but sadly there is no such thing as a free lunch as the second law rears its ugly head in advanced thermodynamics. Second law says there is no such thing as a free lunch, systems always go from more ordered to less ordered so there no such thing as reversible system which is what you are proposing to store power. The way this disorder is tracked is by entropy. So given the entropy always happens, the trick is to minimize it and compressed air is not a great medium to do it with.

                            The short hand for energy storage is wire to wire efficiency and CAES has pretty crappy wire to wire efficiency. Its been done on a large scale but the big reason is that with natural or unnatural underground caverns a lot of energy can be stored for relatively low capital cost. Pumped hydro storage is similar, a lot of power can be stored but unless there is natural feature it can be far more expensive to build. Its more efficient wire to wire. In both cases if you skip converting the air or water back to electricity the wire to work efficiency increases. So in the case of water, if you want to water the garden fill up an elevated tank with spare power and then run the hose to the garden rather than turning it back to electricity to run a pump. With air, compress the air in a big tank and run air tools off it. Batteries are fairly efficient wire to wire and their power density is high and getting higher and that is why the world is going to be using a lot more of them. .

                            Comment


                            • #15
                              Originally posted by happy_hipster View Post
                              I generally regard views like this to be put in the category of "If people could fly, we woulda dun it already" Efficiency is something that comes with R&D, and so do breakthroughs. I think ideas like this dont get off the ground because they would be a solution to an expensive problem. The problem is not the efficiency of the capture of power, in this case, it is in using expensive, explosive, toxic DISPOSABLE batteries.

                              Replacing thousands of dollars worth of batteries every 5 to 15 years does not sound very efficient. The reality is that very practical and efficient cars were mothballed for decades in order to continue profiting off of gas guzzlers, and it is only now they are being re-introduced because, well, they have to.

                              It really seems that there is more feedback about why it is absolutely infeasible to make an alternative to chemical batteries, and little to nothing about how we could be smart enough to make it work. Maybe you are right, maybe we are all too stupid to make an efficient pneumatic battery. Maybe no one has the knowledge or training to even imagine it. I dunno.

                              I hear Einstein created the concept of a three gas system for a refrigerator that worked without pumps, we just have not figured out how to do it yet, or dont WANT to because a permanent sealed refrigeration unit without moving parts is not disposable, and therefore not profitable.
                              It isn't that your ideas won't work. It's just that they have poor efficiency and (meant as a reality statement) are in many ways unworkable for reasons you don't understand. The laws of Thermodynamics are against you on this one and so far, no amount of R & D has conquered them.

                              You will serve yourself well to brush up on Thermodynamics if you want to continue this dialog. Until you do, it'll be difficult to have a meaningful exchange of information with you. If you do, you'll see where many others have covered this ground and have made their peace with it. Right now, it appears to me and maybe some others that you don't know what you don't know, including the idea that you're embarrassing yourself with your ignorance.

                              Welcome to the forum of few(er) illusions.

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