Here’s an article [1] from last year about the transition of Google’s NL datacenter to use surface water to cool their servers. It mentions the DC uses both op

Here’s an article [1] from last year about the transition of Google’s NL datacenter to use surface water to cool their servers. It mentions the DC uses both open and closed loop cooling, and you can see a picture of the heat exchanger, so it seems you are correct (at least for this DC). [1] https://www.dutchwatersector.com/news/google-nl-switches-to-surface-water-for-its-datacentre-cooling https://www.dutchwatersector.com/news/google-nl-switches-to-...