I’ve always thought about building a solar chimney dug into ground, with screens and filters and possibly extra racks with material that self wetted to add evaporation into the ‘fridge’ to reduce temps / add humidity- or alternatively wrapping ‘ fridge’ container externally with self wetting ( material that has a corner in a large tank of water will wet itself) , my house is built on a hillside so the basement level would be buried/ wet wrapped,( in summer only ) then as it came into the ground level into my single story north side attached porch - where it would have the food for access in the house- and the container would continue thru the roof as a small solar chimney- to continually pull colder air thru ( with appropriate filters below food storage area.