If like to see a true engineer mock or what it would entail. I think it would require a dedicated facility to pull it off given just how much heat needs removed and the volume of water used. The problem is there is an insane amount of heat energy from these DCs. It has to go somewhere, and water is a very good medium for that. That heat still has to go somewhere, so removing it from the water is much harder. If you had a huge setup of heat exchangers, they could probably do it with enough time and space, but time isn't an option, because they run continuously. It would probably end up being just a huge holding tank that lets the hot water cool over time.

I don't think anything like solar is going to help. It would be good environmentally to offset some of their power consumption, but I think it would be negligible in their overall power draw and wouldn't have any effect on their cooling. It's not like they are cooling airspace, which they also are, but it's the components themselves.