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Hi Zack, My company, LightSail Energy, is developing precisely this technology. www.lightsail.com We're also developing the world's lowest cost pressure vess

Hi Zack, My company, LightSail Energy, is developing precisely this technology. www.lightsail.com We're also developing the world's lowest cost pressure vessels to store the air. I wish you had the money to invest in us too ;-)

NicoJuicy 12y ago
Do you have any finished products yet (just wondering)
- DaniFong 12y ago
  Not yet, currently developing our systems to be pilot ready for field tests next year. It's a long, hard business developing new energy tech. Our first genuine products are likely to be our pressure vessels...
zackmorris 12y ago
Wow that's cool. I appreciate how you have some real numbers on your site, it seems approachable. Ya every day I kick myself for not generating a few Bitcoins when I first heard about them, so I could invest in companies like yours.
dredmorbius 12y ago
I'm curious what the magnitude of thermal energy loss without capture and re-injection of heat loss is with CAES. I've seen repeated mention of this in various sources, but no explicit quantification.
- DaniFong 12y ago
  It's hard to generate a strict apples to apples comparison -- not only do the numbers depend on operating parameters, but pure adiabatic operation causes both very high temperatures, imposing strict materials constraints and very difficult heat exchange and heat storage challenges, and very low temperatures, causing icing. This means no working pure compressed air energy storage tech is in existence today -- a couple exist which add heat via combustion, one product used to exist which used an electric heater to keep a heat store warm. Both are thermodynamically non-ideal. Based on pure theory, however, running two stages of compression to 200 bar (14.1:1 each), running perfectly adiabatically during compression and expansion, temperatures would reach to about 600 C during compression. If one didn't recover the heat of compression, and let the temperature of the compressed air drop to ambient, the temperature upon expansion would get to about -170 C. Pure thermal efficiency would be about 34%. The results are so extreme / bad that one would choose a whole separate set of parameters and compromises. But that should show you the power of direct contact heat exchange.
  - dredmorbius 12y ago
    Thanks. I've seen some discussion of CAES using former natural gas wells for storage. I don't know the scale of operations there, but it could be large (meaning that relatively small amounts of energy would be stored or extracted at any given point in time. Rock also serves as a pretty good insulator (R5 as I understand, and there's a lot of it), which might preserve some of the heat of compression. In your example, is 200 bar a typical pressure for CAES? I see that as about 2900 psi for the imperial units types.
    - DaniFong 12y ago
      200 bar is an inflection point in the regulatory landscape for above ground tanks. A sweet spot. There's another sweet spot around 300 - 400 bar due to the physics of air. Salt caverns melt at high enough temps (above 200 C) and injecting hot air into a methane reservoir is not terribly advisable...
      - dredmorbius 12y ago
        Took me a moment to realize you were talking CAES in salt caverns, not salt caverns for thermal energy storage, though that hadn't occurred to me either (I don't think it's necessary). The constraints you raise on natural-formation CAES do raise some interesting challenges (or Hollywood movie plots).

NicoJuicy 12y ago

Do you have any finished products yet (just wondering)

DaniFong 12y ago
Not yet, currently developing our systems to be pilot ready for field tests next year. It's a long, hard business developing new energy tech. Our first genuine products are likely to be our pressure vessels...

zackmorris 12y ago

Wow that's cool. I appreciate how you have some real numbers on your site, it seems approachable. Ya every day I kick myself for not generating a few Bitcoins when I first heard about them, so I could invest in companies like yours.

dredmorbius 12y ago

I'm curious what the magnitude of thermal energy loss without capture and re-injection of heat loss is with CAES. I've seen repeated mention of this in various sources, but no explicit quantification.

DaniFong 12y ago
It's hard to generate a strict apples to apples comparison -- not only do the numbers depend on operating parameters, but pure adiabatic operation causes both very high temperatures, imposing strict materials constraints and very difficult heat exchange and heat storage challenges, and very low temperatures, causing icing. This means no working pure compressed air energy storage tech is in existence today -- a couple exist which add heat via combustion, one product used to exist which used an electric heater to keep a heat store warm. Both are thermodynamically non-ideal. Based on pure theory, however, running two stages of compression to 200 bar (14.1:1 each), running perfectly adiabatically during compression and expansion, temperatures would reach to about 600 C during compression. If one didn't recover the heat of compression, and let the temperature of the compressed air drop to ambient, the temperature upon expansion would get to about -170 C. Pure thermal efficiency would be about 34%. The results are so extreme / bad that one would choose a whole separate set of parameters and compromises. But that should show you the power of direct contact heat exchange.
- dredmorbius 12y ago
  Thanks. I've seen some discussion of CAES using former natural gas wells for storage. I don't know the scale of operations there, but it could be large (meaning that relatively small amounts of energy would be stored or extracted at any given point in time. Rock also serves as a pretty good insulator (R5 as I understand, and there's a lot of it), which might preserve some of the heat of compression. In your example, is 200 bar a typical pressure for CAES? I see that as about 2900 psi for the imperial units types.
  - DaniFong 12y ago
    200 bar is an inflection point in the regulatory landscape for above ground tanks. A sweet spot. There's another sweet spot around 300 - 400 bar due to the physics of air. Salt caverns melt at high enough temps (above 200 C) and injecting hot air into a methane reservoir is not terribly advisable...
    - dredmorbius 12y ago
      Took me a moment to realize you were talking CAES in salt caverns, not salt caverns for thermal energy storage, though that hadn't occurred to me either (I don't think it's necessary). The constraints you raise on natural-formation CAES do raise some interesting challenges (or Hollywood movie plots).