Mission Critical - Winter 2008 - (Page 8)

Cronin’s Workshop BY DENNIS CRONIN Dennis Cronin has been in the mission critical industry for more than 30 years. In that time, he has completed more than 4 million square feet of mission critical space. He is a founding Member of 7x24 Exchange, and an advisory board member of Mission Critical. Imagining the perfect data center power and cooling solution Help Dennis and win a Mission Critical coffee mug T he difficulty of removing the ever-increasing heat loads in the data center continues to challenge even the most diligent engineers, manufacturers, and end users. Skyrocketing energy costs and diminishing energy reliability make continuous operations more difficult and expensive. While processing densities have rapidly increased, data centers have propagated, and energy costs gone through the roof, we’ve seen little true innovation in addressing data center power and cooling problems. The problem: Server cabinets now burn 12, 18, 25-kilowatts (kW) and more of power. • Old technology is slowly decommissioned so total site power/cooling increases • Cooling systems cannot match the added heat load • Companies are moving from two data centers to triangulating operations among three • The price of oil flirted with $100 per barrel in January; expect electricity and gas prices to follow I’ve outlined a tiered solution that is simply an aggregation of time-tested tools and systems that are readily available. I’ve also described a radically different solution that addresses the shortcomings of the familiar solutions. The Tiered Solution: Raised-Floor Distribution Cabinet-Based Systems Water-Cooled Processors Introducing “Cronin’s Workshop” Win a Mission Critical coffee mug The enormous creativity of our industry means that we face radical changes in the way we design, build, operate, and maintain mission critical facilities. Making this change will demand strong debate about what is right, wrong, and best practice. We have created “Cronin’s Workshop” to foster this debate. Each month our columnist Dennis Cronin will describe a problem and pose a solution. We want to hear what you have to say about these problem/solutions posed by Dennis. In the subsequent issue we will publish the best positive and negative opinions received from readers. Next issue we will discuss the correct applications of “Free Cooling” • Why it has failed so miserably in the past • Risks in applying it to a data center operation • How it can succeed now. Raised-Floor Distribution. Most basic data centers use cooling delivered via the under-floor plenum from computer room air conditioners (CRACs) that take and cool the warm air in the computer room before discharging the cold air back into the plenum. The cold air is released into the computer racks via floor cutouts and perforated floor tiles. Raised floor height restrictions, underfloor obstructions, and the CRAC unit capacities limit the effectiveness of this basic cooling process. It is generally accepted that the upper limits of cooling from this method is in the range of 8 to 12-kw per rack or 120 to 150 watts per square foot (W/sf). More than 15 years ago, I led a live test of data center cooling that concluded that as a data center approaches 100 W/sf, the footprint of the CRACs begins to equal the footprint of the electronic equipment. Deeper raised floors have pushed this limit to 150 w/sf. Cabinet-Based Systems. With newer technology pushing past 20 kW per rack and 150 W/sf, the industry has turned to spot cooling of high-density racks. First manufacturers added fans to move more air through the racks. This increased rack cooling but also introduced heat load from the fan motors, thereby reducing the overall data center capacity. Next the industry turned to cabinet-mounted cooling systems. These entail mounting a water- or Freon-cooled coil on the front, back, sides, top, and/or bottom of the rack. These designs used fans to re-circulate rack air between the coil and the electronics in the rack. This removed heat generated from electronics from the room; however, the designs place the electronics at great risk from water in the racks as well as from the added piping, valves, fittings, and liquids throughout the data center. Further, routing pipes through the underfloor of existing data centers it is not always practical. In new data centers, this design requires higher raised floors (over 24-in), which many facilities cannot accommodate due to floor-tofloor height limitations in most multi-story buildings. Water-Cooled Processors. Last, the industry is turning to direct water-cooling of the processors. Water cooling removes the most heat in the most efficient manner, but the presence of pressurized hoses, connections, and manifolds within the rack and in close proximity to the electronics poses 8| Mission Critical Winter 2008

Table of Contents Feed for the Digital Edition of Mission Critical - Winter 2008

Mission Critical - Winter 2008 Table of Contents Editorial: What Have We Been Doing? Cronin’s Workshop: Imagining the Perfect Data Center Power And Cooling Solution Digital Power: The Next Edge in Business Resiliency Zinc Whiskers: Keeping Up With The Green Movement Mission Critical Care: Shipping, Staging, and Installation Legal Perspectives: “A Reliable Energy Supply Is Key to Data Center Success” Continued Payback, Instant Protection Beyond the Nines The Green Information Technology Revolution Health Care Network Offers Glimpse of the Future of Backup Power High-Density Data Centers – Discuss, Design, Deploy High Performance Data Centers Call for Innovative Cooling Techniques More Data in the Data Center Five Considerations for Powering Data Center Racks New Products Industry News Events Classifieds Letters Ad Index Datacenter Wiki: wiki-Mission Critical

Mission Critical - Winter 2008

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