One of the main factors considered by the design team was how we could re-purpose excess power and HVAC resources that were going unused in the active data room. When we planned out the facility 5 years ago, we anticipated that customers would demand rack environments that could support high power densities. And while we have had some customers deploying as much as 19 kW in a single rack, the majority of our customers have had more modest power requirements. The end result is that while the overall engineering plan for our first data room projected that we would need eight 30 ton Computer Room Air Conditioners (CRACs) to cool the room at full capacity, the reality is that with 85% – 90% of the floor capacity used, we are only running three to four total CRACs even at times in the summer when outdoor heat reached critical levels. So our engineering team came up with a plan to re-direct cooling from the active data room to the new data room. We would knock out penetrations at the top and bottom of the common wall separating the two rooms and assemble both cold air ducting and hot air returns to the CRAC units located on the other side of the common wall. As illustrated below three cold air feeds were constructed to supply air to a common overhead plenum. One of the most important parts of the project was making sure that no contamination from construction debris passed into the active data room. Great care was taken in sealing the areas where the dry wall was to be cut and the active data room was pressurized using the existing exhaust fan systems so that any potential debris was sucked into the new data room.
One feature that allowed us to accomplish our objective was that our Liebert CRAC units were constructed in a manner that allowed us to put the hot air return on either side of the unit. All we had to do was move the hot air returns that were facing into the active data room so that they pointed towards the common wall.
Ultimately, the penetrations were all completed without any disturbance or issues with the active data room. The supply ducts are air-tight and will supply enough air for our initial deployment of approximately 60 racks in the new space. As we grow, the plenum will already be installed throughout the room and we will just need to aid more air handling capacity to meet capacity.