[mariuolo]

The closest thing I remember is Google taking over an old paper mill in Finland that used a condenser sunk into a canal connected to the Baltic sea.

https://www.wired.com/2012/01/google-finland/ there should be a video with the details here.

[brunnsbe]

There's also a data center in Helsinki, Finland that is cooled by sea water and the waste heat produced is piped via a heat pump into the district heating network. Here's a press release from 2011: http://www.investineu.com/content/atos-builds-world%E2%80%99...

[Maxion]

This, it feels like an awful waste to dump the heat straight into the ocean. District heating networks are a very efficient way to heat up a city, and they can be used as a place to dump excess heat. Further, we've now also got district cooling, http://basrec.net/wp-content/uploads/2014/05/District%20Cool... [PDF warning]