Just caught wind of a relatively new airconditiong/heating unit that runs on DC, is very energy efficient and provides both battery back-up and DC power for lighting and ceiling fans.
The SoCool System
It's a pretty slick bit of tech. The 2-ton unit uses 24V DC power and can be fed directly from solar or wind power in DC which it then will store in a battery, use to run itself and can divert to additional DC items like lighting and cieling fans. It also optionally integrates a freezing battery like the Ice Bear which will freeze and decrease power consumption for hours afterwards. The new Millenia 4 even converts condensate into drinking water with an add-on option. And according to their literature the whole mess uses as little as 25% what a traditional unit might for the same tasks.
I've no experience with them but I'm in love with their ideas.