Thermodynamic battery for energy storage

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oli63ro
oli63ro Registered Users Posts: 6
Bellow you can see the schematics (to big picture for this site limit) of a high pressure tank composed from cells distributed in layers. The cells are filled with air thru valves in such a manner so cells from one layer have the same pressure and the pressure from one layer is different from another layer (increasing from the internal layer to the external one. This model offers the possibility of storing very high pressures in safe conditions.
You can check the net to see that air cars travel 200 km with air stored on board at 300 bars. My model offers the possibility of compressing the air at 1000 bars and more.
For renewable energy storage systems this model of tank allows storing air at high pressure in underground or above ground tanks (for home use).
Advantages:

- it eliminates the necessity of using groups of expensive electrical accumulators with a short working life due to the reduced possible number of charging/discharging cycles (from 500 to 2000 but with the storing capacity reducing over time),
- by having the possibility to withstand tens of thousands charging/discharging cycles without any loss in storing capacity;
- at very high pressures compressed air has better energy densities / liter than conventional batteries.
fig1.png
So dear reader tell me what you think about this possibility?
Q&A received until now on other forums.

Q:
1. Does the increased pressure in the inner cells really make up for the increased size and weight of the overall structure associated with the outer cell layers?
2. Do you see the greater safety as resulting from the lower level of energy released if one cell fails compared to a single monolithic tank? If so, what happens if the failure of one cell results in over stressing adjacent cells?
3. I am not at all comfortable with a system whose safety depends on that large an array of individual valves and a control system which coordinates them. What sort of fail-safes in your design address these concerns? If one or more cells in a middle layer fail to pressurize properly, what is the effect on the inner layer cells associated with them?
4. How are the valves and pressure sensors in the inner layers tested and serviced?
A:
1. Increasing pressure = increasing wall thickness for usual tanks. In my patent the same weight is redistributed in inner cell walls, for safety. same weight of the tank but super safety. A bullet will cross the tank and will destroy few cells on his road and the rest of the cells will function with no problem. Inner cells have larger thickness walls.
2. Yes. The walls of the cells are calculated to resist the pressure difference between cell and worst case external pressure. Pcell=F/Scell, smaller S means at the same thickness higher pressure. I have a website explaining this. More on www.jopatent.com
3. If a valve or a group of valves fails only the corresponding cell are blocked the rest of the tank will function at a reduced capacity.
4. Big problem yes. For that reason the patent covers blocks of valves. More on jopatent. There are also constructive solutions for tanks made from block of cells that can be changed in case of failure.

Comments

  • Ralph Day
    Ralph Day Solar Expert Posts: 1,019 ✭✭✭✭
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    Re: Thermodynamic battery for energy storage

    So, this would require a spinning generator run off the stored air? How high a working pressure? Would it work both ways, as the compressor and as the generator, or separate hardware for both? (solar/wind/renewable source runs the compressor to fill the bank, then air motor generates power when no renewables?) How long would your stored source last? How large a volume would this apparatus take up compared to lead acid batteries?

    Sounds interesting.

    Ralph
  • oli63ro
    oli63ro Registered Users Posts: 6
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    Re: Thermodynamic battery for energy storage
    Ralph Day wrote: »
    So, this would require a spinning generator run off the stored air? How high a working pressure? Would it work both ways, as the compressor and as the generator, or separate hardware for both? (solar/wind/renewable source runs the compressor to fill the bank, then air motor generates power when no renewables?) How long would your stored source last? How large a volume would this apparatus take up compared to lead acid batteries?

    Sounds interesting.

    Ralph

    1)Yes, a generator or a turbine that moves the generator.
    2)No theoretical limits. Only technological and cost limits. More on jopatent.
    3) Depending on the type of generator used both solution colud work.
    4) If valves are good enough time.
    5) Depends on the manufacturing technology and the dimensions of the valves used smaller cells means higher pressure possible. Compared with electrical batteries following aspects occur:
    - it eliminates the necessity of using groups of expensive electrical accumulators with a short working life due to the reduced possible number of charging/discharging cycles (from 500 to 2000 but with the storing capacity reducing over time),
    - tanks have the possibility to withstand tens of thousands charging/discharging cycles without any loss in storing capacity;
    - at very high pressures compressed air has better energy densities/liter than conventional batteries.

    One interesting theoretical aspect of the termodhynamics that results when you fill this tank is the fact that the temperature inside the tank decreasses from internal layers toward external layers (Polytropic process - Pressure on layer i-1/Temperature on layer i-1 = Pressure on layer i/Temperature on layer i) in steps. There are multiple implications of this phenomenon. If you take the heat out of the compressor (you can generate steam), than you have a heat source at high temperature and on the external layers of the tank a lower temperature (lower than the ambiental temperature). This temperature difference could be used to recover a portion of the energy that you lose when you compress air. In a Carnot cycle that means higher efficiency (if an adiabatic process is used, efficiency=1-T2/T1 and T2 could go near 0 K for large scale systems)
    If I'm right this could be an important factor for implementing this type of process)
  • danielh
    danielh Solar Expert Posts: 69 ✭✭✭✭
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    Re: Thermodynamic battery for energy storage
    oli63ro wrote: »
    Bellow you can see the schematics (to big picture for this site limit) of a high pressure tank composed from cells distributed in layers.

    I see the appeal of compressed air storage (http://www.scientificamerican.com/article.cfm?id=gathering-the-wind).

    But I Gotta ask this simplistic question: how comfortable would the average home owner be with a potential bomb in his basement? Can one really trust that the material used to construct
    this complex compressed air storage device just-won't-fail?
  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
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    Re: Thermodynamic battery for energy storage

    What kind or efficiency do you expect? losses across system energy in to energy out? Compressing air isn't easy. I would expect in a small system you could only store a tiny percent, though perhaps there is a size where this would be cost effective...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
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    Re: Thermodynamic battery for energy storage

    I think the possibility of valve or metal failure is extremely high at 1000 bar,on such a complicated item. I think if it was in your basement and it failed you would find you house orbiting up next to the space station.
    I really think trying to compress large quantities of air to that pressure on a bulk commercial scale is beyond any engineering company to build the tanks and all the other equipment necessary to compress the air at a price that would not be less than hundreds of times the cost of just about ANY battery.
  • Ken Marsh
    Ken Marsh Solar Expert Posts: 114 ✭✭✭✭
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    Re: Thermodynamic battery for energy storage

    Two problems.

    1. When you compress air, more energy is expended heating the air than the actual pressure increase.
    Unless you have a method of recovering this heat energy the process is going to be most ineffiecient.
    Same thing when you expand the air.
    Unless you can make use of the temperature difference produced you will be able to recover only a small porting of the original energy.

    2. For any kind of efficiency you must match the expander to the pressure difference.
    But there are several pressures in the accumulator.
    This makes it very difficult to recover the energy with any kind of efficiency.
  • oli63ro
    oli63ro Registered Users Posts: 6
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    Re: Thermodynamic battery for energy storage
    danielh wrote: »
    I see the appeal of compressed air storage (http://www.scientificamerican.com/article.cfm?id=gathering-the-wind).

    But I Gotta ask this simplistic question: how comfortable would the average home owner be with a potential bomb in his basement? Can one really trust that the material used to construct
    this complex compressed air storage device just-won't-fail?

    In a conventional tank, one valve failure or a crack in the wall and the whole tank kaboom, my model: valve failure or a crack will release the pressure just from the affected cells, that means smaller amounts of air. For home use valves can be automated and so no need of sensors and electrical commands. The complex schematics is for complex solutions where you can play with thermodynamic processes conducting gasses and corresponding heat as needed.
  • oli63ro
    oli63ro Registered Users Posts: 6
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    Re: Thermodynamic battery for energy storage
    Ken Marsh wrote: »
    Two problems.

    1. When you compress air, more energy is expended heating the air than the actual pressure increase.
    Unless you have a method of recovering this heat energy the process is going to be most ineffiecient.
    Same thing when you expand the air.
    Unless you can make use of the temperature difference produced you will be able to recover only a small porting of the original energy.

    2. For any kind of efficiency you must match the expander to the pressure difference.
    But there are several pressures in the accumulator.
    This makes it very difficult to recover the energy with any kind of efficiency.

    1) Yes it's true. I'm only offering the solution to store in safe conditions, high pressures. Recovering technologies are necessary. Steam generators, Stirling engines, or Peltier - Seebeck modules could do the job.
    2) If several pressures can work in the same volume I think that the same principle in reverse can be used so you can obtain the desired pressure in the expander.
  • oli63ro
    oli63ro Registered Users Posts: 6
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    Re: Thermodynamic battery for energy storage
    john p wrote: »
    1)I think the possibility of valve or metal failure is extremely high at 1000 bar,on such a complicated item. I think if it was in your basement and it failed you would find you house orbiting up next to the space station.
    2)I really think trying to compress large quantities of air to that pressure on a bulk commercial scale is beyond any engineering company to build the tanks and all the other equipment necessary to compress the air at a price that would not be less than hundreds of times the cost of just about ANY battery.
    1)Statiscally not all valves or walls fail at the same moment. Only one or few at one meoment. So instead of KABOOM, small crackling noises. Sorry, no chance to go orbiting.
    2)Maybe yes, maybe not.
  • oli63ro
    oli63ro Registered Users Posts: 6
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    Re: Thermodynamic battery for energy storage
    Photowhit wrote: »
    What kind or efficiency do you expect? losses across system energy in to energy out? Compressing air isn't easy. I would expect in a small system you could only store a tiny percent, though perhaps there is a size where this would be cost effective...
    One interesting theoretical aspect of the thermodynamics that results when you fill this tank is the fact that the temperature inside the tank decreases from internal layers toward external layers in steps (Polytropic process - Pressure on layer i-1/Temperature on layer i-1 = Pressure on layer i/Temperature on layer i). There are multiple implications of this phenomenon. If you take the heat out of the compressor (you can generate steam), than you have a heat source at high temperature and on the external layers of the tank a lower temperature (lower than the ambient temperature). This temperature difference could be used to recover a portion of the energy that you lose when you compress air. In a Carnot cycle that means higher efficiency (if an adiabatic process is used, efficiency=1-T2/T1 and T2 could go near 0 K for large scale systems resulting theoretical efficiency near 1). So as a result you have high pressure compressed air at room temperature and you can recover a portion of the energy used for compressing air. This could work maybe for large scale systems. More on jopatent.
    If I'm right this could be an important factor for implementing this type of process.
  • garlmike
    garlmike Registered Users Posts: 14
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    Re: Thermodynamic battery for energy storage
    Photowhit wrote: »
    What kind or efficiency do you expect? losses across system energy in to energy out? Compressing air isn't easy. I would expect in a small system you could only store a tiny percent, though perhaps there is a size where this would be cost effective...

    Somewhere I read it takes 5 HP to give back 1.5 HP. Its a poor way to store energy but it's do able only if the Excess can be stored for months. And if you could stop the rust.