>>1090029They do, but the type in the OP is of course limited. That type absorbs more than it reflects, but also releases that energy back at you. They are great for blocking the prevailing wind, but are best with 3 sides.
For proper reflection, drape an emergency blanket on the fire side. They become amazing then. Keep in mind that if you are going to use an emergency black for a reflector, you don't need a solid wall. You only need a a couple sticks/trees to tie up the emergency blanket. That's far less work and more LNT too. You can pack light weight poles with your tent and use those if you think you'll not have sticks to find on site.
You can also couple it with this type of setup, though using an emergency blanket for this will be much better.
