The black cans are the same, I am just using a longer air path that will heat the air considerably more.  I am using a zig-zag connection of cans so that instead of just going top to bottom, the air goes thru every can. Also, I am not using silicone, but epoxy which is easier to work with, imho. And it is very durable and less bulky than a caulk would be.

If you don't use epoxy, start! It is a great adhesive.

I'm also using some aluminum flex to conjoin the cans.

My unit is not going to occupy a window, as windows help direct sunlight heat the house. It will sit on my roof and have heat enter through a hose with a fan at the end to pull air in.