https://www.techpowerup.com/269057/alphacool-announces-water-cooling-solutions-for-server-racks
 
As hardware gets increasingly more powerful it generates more and more waste heat. This can lead to thermal problems, especially with server racks that have the hardware packed so close together. Compact air coolers are hardly able to dissipate the excess heat from processors. It becomes even more problematic when one or more graphics cards also need to be cooled. At full load processors and graphics cards struggle with temperatures and can quickly start to throttle down their clock rates early due to thermal throttling.

Many server operators want simple and cost-effective solutions to solve this problem. Therefore, Alphacool has developed and launched a whole range of water cooling sets for 1 to 4U server racks in cooperation with its Enterprise Solutions customers. All sets can also be individually extended or adapted. Quick-release fasteners, additional pumps, radiator, and graphics card coolers can be added by arrangement and the components can be adapted to individual requirements. The sets are delivered to the customers pre-filled.
 
Many server rooms I have seen are in air-conditioned rooms so this solution could reduce air-conditioning requirements, saving money.