Room dividers and free standing screens are mostly used as a way to visually block out parts of a room. But they can also be used in a more utilitarian way, by blocking draughts and keeping a room sheltered from the cold.
To do this with an existing screen, first you need to find the source of any draughts or places that you suspect heat dissapates from a room. Then simply place the screen/s in a perimeter around that area. The screens will then slow down the heat loss from the area behind it.
You will need a certain type of screen for this to work though. Preferably one that is flush with the floor and reaches at least a few meters into the air. Screens made of thick fabric are very effective at blocking out draughts, so make use of any drapes or large pieces of material by layering them up on the walls of a screen.