A very old idea, and a good one.
Old adobe structures, way back to the Indians, were designed to retain heat at night and keep heat out during the day, using the mass of the walls.
Same for sod houses.
In Arab nations, buildings were designed the same way, sometimes including vented towers that encouraged air movement inside the buildings.
Some modern solar heating systems use melting salts to absorb heat during the day, and the heat released by solidification to heat the building at night.