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Rick Thomas has been known to say he’ll “never buy an enclosed rack system” because everything he’s ever used has “plenty of air flowing around it.”

The Quad/Graphics data center manager changed his mind following his latest data center installation at the commercial-printing company’s data center in suburban Milwaukee.

“Not only did I have to rethink that, but I came to the conclusion that I was wrong,” Thomas says. “Not only am I installing closed racks, I’m now completely sealing them too.”

What changed his mind? The need to consolidate a 2,000 sq ft data center and an 11,000 sq ft data center the company inherited through an acquisition into one 3,000 sq ft facility.

When CRACs just won’t cut it

The first choice for solving his high-density issue was a forced-air solution, which proved to be ineffective in the amount of space Thomas was working with.

“With some of the physical room limitations we had, there was no way we could use forced air and drive the densities we wanted,” he says.

After evaluating several options, Thomas’s team settled on Rittal’s LCP+ air-to-water cooling system.

Ron Vissers, a data center project manager at Quad/Graphics, says the team looked at 100 or more CAD designs using traditional cooling solutions and Rittal’s LCP products.

“We did some serious comparisons between Computer Room Air Conditioning (CRAC) and the chilled-water scenarios, and the LCP system repeatedly came out on top for efficiency,” he says.

Not only did the Rittal system completely address the room’s structural limitations and provide better cooling efficiency than other options, it also offered the ability to maximize the use of free cooling, Vissers says.

Sold on liquid cooling

They were sold and shortly thereafter Quad/Graphics’ new data center had 19 LCP+ units cooling its 24 Rittal model TS8 enclosures.

The team also added four of Rittal’s passive rear-door heat exchangers, which also use air-to-water technology. They included the rear-door units to address a very specific problem: the heat generated by storage arrays.

“Even as these [storage] components require less and less physical space, they generate more heat,” Thomas says. “The rear-door coolers take all that into consideration and do the job in a confined space.”

Warmer water and warmer air

The data center’s inlet-air temperature on day one was 74F, and the managers have a plan to raise it gradually over time. As the inlet temperature rises, more free cooling can be used and the chillers use less power.

The data center team reduced the chillers’ power draw further by cooling its chilled water to 55F instead of the standard 45F. “Running our cooling water at 55F as opposed to 45F allows our 120-ton cooling system to work as if it were a 140-ton system,” Vissers says.

They also have a wide humidity envelope on the data center floor, which saves energy by reducing the necessary amount of dehumidification.

Savings in numbers

Here’s how much Quad/Graphics expects to save on cooling yearly by not going the CRAC-route:

• Combined CRAC costs: $82,149 per year
• Rittal chillers plus free cooling: $19,129/year
• Annual savings: more than $63,000

What’s more? Quad/Graphics tells Rittal that these numbers could be on the conservative side since they have been able to virtualize, consolidate and retire more components than originally planned, so they aren’t demanding as much power as they expected from the start.

About the authors: Chad Sewell is a data center solutions specialist at Rittal. A.D. Horn is a marketing communications specialist at Rittal.

Disclaimer: views expressed above are those of the authors and do not necessarily reflect the views of DatacenterDynamics