In tropical country is there a condition for home or mobile that run on solar?
Look to local designs before there was cheap electric for guidance.
eg the islamic design of a courtyard fountain and a tower/chimney to create a through draft over the water. plus tiles and suitable shading.
or simple thatched huts, high thermal mass, shading and few windows
or raise on stilts to get draughts…
For old land rovers you can get a double skin roof to keep cool.
If you want to use a mechanical system heat pumps give best efficiency