Homes in bipolar climates store heat in their thermal mass during the day, releasing it at night. Which is great . . .during the winter. Not so great in the summer.
Before energy-hungry compressor-based air-conditioners were commonplace in the home the solution was to stick propeller fans in the
windows, blowing external air in one side of the domicile and out the other. Uncomplicated. Of course the only thing actually cooled was the air: walls, ceilings and floors - untouched by airflow - continued to radiate heat throughout the night, parboiling insomniac occupants.
Unlike a propeller fan, a squirrel cage* fan sucks air in the front and blows it out the sides, radially. It looks like a hamster wheel.
Sited in a window it will suck cool air from the outside and blow it along the wall (thence floor, ceiling), quickly removing the source of all-night radiant heat from the path between ingress and egress fans.
As well as being quieter and more effective, a design including rim-mounted motor and magnetic bearings will allow a window to still be a window.
* sorta makes one wonder what people did for entertainment, before television.