I need an air current in this room, even when the sun shines directly into it.
I was thinking covering the hopper window with either paper or reflective foil and leaving it a bit open, but I don’t know if this is a stupid idea.
A closed window means an unlivable room.
Look at aluminet. Woven thicker aluminum foil into a reflective sheet that wind can pass thru. You can specify the weave density to choose the % light blocking for your preference of wind and shade trade-off. I’ve got a 70% blocking one and use it a lot for camping in the desert. Available in different sizes and they come with a border that has ring holes for securing.
Looking at the price I think I will stick with dust sheets. But that stuff probably does look a bit nicer.