3 ms·

I wonder if in the time since this was written if anyone has found a good source for small turbo expanders. Liquefied air is a potentially interesting mode of

by nullc 2y ago

I wonder if in the time since this was written if anyone has found a good source for small turbo expanders. Liquefied air is a potentially interesting mode of energy storage for islanded solar because it doesn't require high pressure storage (which has safety concerns)-- for that application the round trip efficiency isn't critical as there is nothing else to do with the power... but it can't be a total joke. And the basic JT cycle is really poor. I understand that simply adding an expander and another heat exchange stage can improve it a lot.

sandworm101 2y ago
If you are dealing with liquid nitrogen from air, then you are probably also dealing with liquid oxygen in the mix. I imaging that at power-storage scales the presence of such amounts of liquid oxygen might create safety issues. Separating it out might nullify any energy storage advantages.
- 0cf8612b2e1e 2y ago
  You could embed the chiller in a nitrogen only environment. I am imagining a closed loop system where you are cooling/using the nitrogen on a daily basis.
- nullc 2y ago
  It's not all that energetically disfavorable to extract oxygen if you're already compressing the gas. There is a lot of demand for concentrated oxygen too, so one could manufacture it as a side product instead of storing it. As far as 'closed loop' sadly that does break the economics, I think-- part of the reason why cryogenic nitrogen storage is interesting is because the nitrogen expands 800 fold at atmospheric pressure, so the container for the decompressed nitrogen would be gigantic.
  - voakbasda 2y ago
    I would wager that the regulations governing LO2 generation facilities preclude pursuing that as a side product. I imagine lots of red tape, either already in place or coming soon -- right after someone blows up their neighborhood trying.
  - yetihehe 2y ago
    Or you can use that liquid oxygen to precool your input, saving some energy over just venting it.

by nullc 2y ago

sandworm101 2y ago

If you are dealing with liquid nitrogen from air, then you are probably also dealing with liquid oxygen in the mix. I imaging that at power-storage scales the presence of such amounts of liquid oxygen might create safety issues. Separating it out might nullify any energy storage advantages.

0cf8612b2e1e 2y ago
You could embed the chiller in a nitrogen only environment. I am imagining a closed loop system where you are cooling/using the nitrogen on a daily basis.
nullc 2y ago
It's not all that energetically disfavorable to extract oxygen if you're already compressing the gas. There is a lot of demand for concentrated oxygen too, so one could manufacture it as a side product instead of storing it. As far as 'closed loop' sadly that does break the economics, I think-- part of the reason why cryogenic nitrogen storage is interesting is because the nitrogen expands 800 fold at atmospheric pressure, so the container for the decompressed nitrogen would be gigantic.
- voakbasda 2y ago
  I would wager that the regulations governing LO2 generation facilities preclude pursuing that as a side product. I imagine lots of red tape, either already in place or coming soon -- right after someone blows up their neighborhood trying.
- yetihehe 2y ago
  Or you can use that liquid oxygen to precool your input, saving some energy over just venting it.