The other water-cooled data center

Once-through water heat rejection systems, more commonly known as once-through cooling systems, are widely used in energy-intense industries due to their efficiency and reliability, yet remain rarely used in data centers. A small but growing number of colocation providers are taking the opportunity to use once-through cooling to deliver efficiencies, and in some cases high-density racks, to their customers. This report explores different designs and provides real-world case studies of colocation providers using them.

KEY POINTS

• Unknown or untested technical and administrative details, from mechanical engineering to building permits, can stymie cost benefit analyses for once-through cooling designs — but a strong business case typically follows.
• Operators of once-through cooled data centers say upfront engineering efforts are non-trivial.
• The success of a project often depends on how creatively a technical team responds to the specific needs of each site.
• The energy efficiency and environmental sustainability benefits of once-through cooled data centers will likely become too attractive to ignore when considering siting and design for new builds.