First comes the framing, of course. Good building practice calls for pressure treated lumber on the bottom against the concrete, and I think untreated lumber should be OK for the rest of it.
The end studs are screwed to the walls and the bottom 2 x 6s are screwed to the floor with Tapcon screws.
Since there is drywall on the basement walls, I covered it with plastic to protect it from any condensation that might seep through from the cooler.
Insulation recommendations from the Cool-Bot folks say to use 4 inches of foam. Since there were already 2 inches of foam on the basement walls, I added a 2 inch foam piece to each one. The foam could be glued on, but I used long screws and fender washers to hold them.
In the wood-framed walls, I cut the foam slightly oversize and pushed it into place. The snug fit was all it needed to stay put. Where there were gaps, I used spray foam and that really locked the rigid foam into place.
Next went on an exterior door and some cheap 5 mm plywood. An exterior door is important because it is insulated and it has good seals. It’s pretty tough (at least for me) to try to build something that will be as well sealed as the factory-made door. When I’m inside with the door closed, I can see only a tiny sliver of light at one corner of the door. Two foam panels are on the floor covered by plywood, and I put a few trim boards here and there and to help hold on the flimsy plywood.
I picked up a used 12,000 BTU/h LG brand air conditioner, which is probably overkill for the size of the cooler, but the price was right. Inside, the cooler measures about 4 feet x 5 feet x 8 feet tall. In hindsight, making it 8 feet tall was probably not the best idea. Seven feet would have been plenty.
The small black box you see below the AC unit is a device called a Cool-Bot controller. It controls the AC so that the temperature inside the cooler can get much colder than the AC could normally get it, and also keeps ice from building up on the AC unit. You can check out the Cool-Bot at Cool-Bot.