i would like to do passive solar heat from an upstair west facing window

[dembotoz]

70s condo. north and west facing windows...has to be internal only....condo association does not have sense of humor....
unused bedroom currently. just storage. big window usually cover in plastic for added insulation...thinking of putting a layer of thin
black plastic out side the open blinds to capture a bit of heat....

open top and bottom for ventilation ......think i have some plastic downstairs....worth the bother?

ideas?...live in southern wisconsin