Liquid-cooling devices were installed on server racks in a data center at Lawrence Berkeley National Laboratory (LBNL) in Figure 1. The passive-technology device removes heat generated by the servers from the airflow leaving the server rack. This heat is usually transferred to cooling water circulated from a central chiller plant. However at LBNL, the devices are connected to a treated water system that rejects the heat directly to a cooling tower through a plate-and-frame heat exchanger, thus nearly eliminating chiller energy use to cool the associated servers. In addition to cooling with passive heat exchangers, similar results can be achieved with fan-assisted rear-door heat exchangers and refrigerant-cooled rear-door exchangers.
Author(s): Mathew, P., B.Tschudi, and S. Greenberg