Comment by scoot
2 days ago
Isn't this effectively neutral over time? Heat generated during compression, lost during decompression, so basically using the air as a heat storage medium?
2 days ago
Isn't this effectively neutral over time? Heat generated during compression, lost during decompression, so basically using the air as a heat storage medium?
I think what he's saying is you can boost efficiency if you compress a cooler gas. So if you could capture the "cold" that you get from discharging the device, and use it to pre-cool the air for the next cycle (or use it for the data centers cooling system) , it would be much more efficient.
Cooling is rarely done in any other way than compressing a gas, allowing the heat to dissipate and then allowing it to decompress again. You don't want to compress a gas to cool another gas about to be compressed. What reasonably advanced compressed gas storage systems do is capture and store the heat that gets created during compression and feed it back during decompression. This gives the same efficiency difference as compressing some magically pre-cooled gas would do, only on the discharge side.
So far so good, just the old thermodynamics. It gets interesting when you have a cooling use case anyways: then you can skip on some of the decompression recovery and use the "cold" from decompression directly, to cool down something that needs cooling, without going the extra way of converting back to electricity and then sending the electricity recovered into a compressor setup for "creating cold". Bonus points if you also have a use case for the heat you did not use in reconversion to electricity, but chances are between losses during storage and heating some the gas back some amount beyond neutral you won't have much spare heat anyways.
Yes. A large radiator would handle both. I assume they just store the heat because hot water will be a lot more efficient at reheating the co2 than night time air and a pool with an insulated cover is not hard to construct.