Battery powered fans - cram it full of batteries, set it up like a trap/bedroll, and it keeps everything within a square or two a small bit cooler than the outside temperature.
Swamp coolers - if you’ve never seen one before they’re basically a big fan that runs the air over a big, wet, absorbent surface which cools the output via evaporative cooling. Since we don’t have normal electrical outlets in Cataclysmworld perhaps you’d stuff it full of batteries and water (if it’s possible to have an object that requires two fuel types at once) and once active, it would keep a small radius of squares around it a good bit cooler than the ambient temperature.
Automotive AC. Seriously, it’s not even been an option on cars for decades in RL; they all come with it standard now. Perhaps while you’re driving you could toggle it on and off via the vehicle context menu. Maybe it needs a special component, maybe it only works if your seat has a roof tile over it, maybe it eats a little extra fuel as a limiter.
Even better and simpler would be the option to use rags/bandanas along with water to gain a short-lived evaporative cooling cloth to wear around your head/neck.
Cooling vests would be extra nice to have in the scorching heat of summertime (perhaps just an article of clothing that has a negative warmth number if that’s even possible) perhaps you could find them in sporting goods/hardware stores/hospitals along with the chemical packs that make them work.
Come to think of it, this is making me want to try modding some of this stuff into the game to see if it’s even possible.
