PhoenixNAP Cooling Infrastructure
On the other side of the wall from the data center floor is a hallway with large 80-Ton Stulz Computer Room Air Handler (CRAH ) units. These are what circulate air through the facility and keep the racks cool. The heat exchange happens in these hallways, but the real cooling happens outside.
Outside the facility, there are chillers that take the water heated by the equipment exhaust and then chill the water for re-circulation. This facility has a yard enclosed by high steel-reinforced walls that houses the power and cooling equipment. First, we are going into the main chiller plant, but one can see that as the second floor is built-out and servers rise in power, that there is a concrete pad already poured for an additional chiller plant in the photo below.
Inside the chiller plant, there are two 700-ton chillers and two 720-ton fully-magnetic chillers.
These chillers take the 55F water that comes from the data center (after a few steps we will get to later) and return water to the data center at 44F.
Outside of the main chiller plant hut, there are stages for media fill cooling towers (a method to increase water to air heat exchange.)
Each chiller has an 8500-gallon tower that will keep the water chilled for approximately 20-25 minutes in the event of an outage so the cool water supply is not lost.
Feeding the facility, there are two water mains coming in from different directions that ensure that there is a water supply even if one feed is shut off.
As a quick aside, if you are wondering what the fixture is on the right side of the photo above where there are cables that go to nowhere, the answer may surprise you. PhoenixNAP uses its own maintenance staff instead of relying on outside contractors. This area is actually a small portion of the training facility next to that team’s offices and lockers. The various fixtures are there to show, train, plan, and test before doing something in the production floor.
There are also two 75,000 gallon water tanks on the campus for backup capacity. One can see those just behind the generators in the distance below.
Phoenix is not known for having the best water. Joe who filmed the video is from Alaska where I personally think the best US water comes from due to it usually coming from glacial melt. Phoenix water is the kind that one can taste that there are minerals and such in the water which is why many households filter water before drinking. In the data center context, the same minerals and pH imbalances can also cause buildup, corrosion, and other challenges for water lines. As a result, the facility has its own water conditioning stage on-site to ensure that the water meets specifications for the cooling loops.
Next, the last major focus of our tour, the power infrastructure.