They should open some warehouses with great insulation and some solar panels and AC. Maybe some stores too. :p
I did some math once and it might be possible, given some fancy material science, to create a suit with its own AC that’s powered by a 5x2ft foldable solar panel.
The only issue is that this is entirely theoretical and no one makes a sufficiently small AC. I think you only needed about half a BTU or so
If it weren’t for cultural issues it would be more popular and cheaper to simply wear a climate controlled suit rather than have AC. There are also some comfort issues that would need to be resolved I suppose.
(For the curious the actual AC portion, fan and coolant would be in a backpack would be in a backpack like device)