[rikkipitt]

I too was wondering that as the ideal gas law states that PV = nRT. When you compress a gas it gets hotter, conversely, allowing it to decompress cools it. I assume they store the heat energy...

https://en.wikipedia.org/wiki/Compressed-air_energy_storage

[Mvandenbergh]

Yes, their website says they have a thermal store.

[mirekrusin]

They should do free ice maker on the other end.