well, they'll be cooking their food anyway
They can put their absorption fridge on the fire with their meal once or twice a day. After an hour over the flame, they let it cool, then stick it in an insulated barrel full of preserved food, vaccines, and other perishables.
I imagine it would find a large market in developed countries too. Tired of coolers full of icepacks that melt? Tired of making a run to the store for bag of ice when camping in the so-called wilderness?