I believe that it’s physically possible to build something like this, but there’s no way it will be cheaper or simpler than cooling on earth. In their comparison table (table 1), they have earth based cooling for a 40 MW cluster over ten years at 7 million dollars and on the right side calculate the space cost as $0 (although they only imply that it would be cheaper than on earth by saying it’s „more efficient“). If you believe that their cooling system will be less than 7 million with enough redundancy for 10 years (or alternatively maintenance or replacement missions), I don’t know what to tell you. It’s not happening.