@ACTupper This is really cool! Can I use this idea in the solarpunk RPG I keep procrastinating on writing?

IRL I really want to use compressed air as a battery system for a DIY solar energy install, as described in Low-Tech Magazine:
https://solar.lowtechmagazine.com/2018/05/ditch-the-batteries-off-grid-compressed-air-energy-storage/
Or maybe use a bike to charge it:
https://solar.lowtechmagazine.com/2023/07/human-powered-air-compressor-and-energy-storage-system/

If I pulled this off, I might want your engine :-)

But I'm just not handy enough to build this myself yet, and I'm not sure how to get help.