Engineered Systems - June 2008 - (Page 20)

CaseInPoint Polypropylene pressure piping system improves server reliability When Utah State University planned to upgrade its data center, improving the server cooling system was a top priority. USU engineers considered using welded steel but had concerns regarding condensation as well as the difﬁculty of installing and repairing the system in an occupied space. “Our problem with the data center was using a piping system that was reliable,” said Lorin Mortensen, a mechanical engineer at USU. “We originally specced stainless steel, but the environment of the data center was not suitable for welding, so we looked at alternatives.” Another option they explored was running single lines of ﬂexible PEX tubing from a main line outside the data center to and from each cooling unit, but it quickly became clear that with the insulation needed to prevent condensation, there would not be enough room to run all the lines cleanly. WELDED PIPE WITHOUT THE FUMES Fortunately, Jon Burrows from Colvin Engineering suggested an alternative system. “We were working with an existing system. We had to maintain the ﬁre protection and the air quality,” Burrows said. “[USU] wanted welded pipe, but without the welding fumes. The Aquatherm system seemed like a good way to give them that.” Aquatherm, a German-based pipe manufacturer, produces a fusible polypropylene system called Climatherm, a system specially designed for heating and cooling applications. While only recently available in North America, Climatherm, and its sister-system Fusiotherm (for potable water applications), have enjoyed decades of success in over 70 countries around the world. Climatherm uses heat-fusion to form connections, a process often used in natural gas piping because of its reliability. Heat fusion bonds both sides of a joint into a single, homogenous material without the use of chemicals or mechanical connections. This tends to eliminate systematic weaknesses and fail-points in the pipe. The heat fusion connections, combined with polypropylene’s resistance to corrosion and abrasion, eliminated the concerns of pipe leaking. The engineers at USU took the innovation a step further by installing the system without additional insulation. Polypropylene has a natural insulation value, and Climatherm is made from over 97% pure polypropylene. Based on the minimum operating temperatures of the system and the maximum humidity levels in the data center, the engineers determined that no condensation would form on the uninsulated pipes during normal operation. Steve Clark, P.E. and president of Aquatherm Inc., stated that, “Based on the temperature of the water in the pipes and the air around it, and the relative humidity of the room, the bare pipe will not sweat, even under extreme conditions. Ironically, if they do insulate it, and someone damages the vapor barrier, then you’ll almost deﬁnitely see condensation.” RE-PURPOSING THE ELEVATED FLOOR USU’s central energy plant provides the chilled water, which is carried through steel mains up to the server room. From there, 6-in. Climatherm lines are ﬂanged directly into the steel and carry the 20 En gi neer ed S y stem s June 2008 These pipes carry 40° chilled water to cooling units throughout the Utah State University Data Center. No insulation is needed to prevent condensation because polypropylene is a natural insulator. water securely into the data center. The ﬁrst phase of the remodeled cooling system supplies 22 APC modular cooling units, with threaded outlets taken from three 4-in. Climatherm branch loops. A second phase, still in planning, will add at least 15 more units on an addition branch line. All the piping is installed inside an elevated ﬂoor, previously used to circulate chilled air underneath the data center. “We’ve been running the system for about a month now,” Mortensen said, assessing the system’s early performance. “We basically have to run the system 24/7. We can’t afford to have any shutdown time. We can isolate zones and units if we need to. It’s allowed us to plan for future expansions.” By integrating the polypropylene pressure piping systems into their design, the engineers at USU were able to avoid many of the major pitfalls sometimes associated with other systems. Corrosion and impact resistant pipes, combined with leak-proof fusion connections, allow for more pounds of cooling to be brought into the data center without jeopardizing the delicate equipment. The result is improved server performance and reliability. “This system saves the owner a lot of ﬂoor space,” Mortensen added. “If we’d installed [ﬂexible tubing], it would have been spaghetti in there. The Aquatherm cleaned it up very nicely.” Sustainable building authority walks the walk when promoting green products “Do what we say and what we do!” might well be the mantra for the Campus Center for Appropriate Technology (CCAT) at Humboldt State University (HSU) in Arcata, CA. When CCAT decided to remodel its live-in demonstration home and educational center for technology and resource conservation, it was done with an eye to sustainability. CCAT, an authority on sustainable building for more than 30 years, knew that the move provided the perfect opportunity to add green amenities to the home. To get the project started, the onestory, 1920s-era home, was lifted from its site and “recycled” by mov-

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Engineered Systems - June 2008 Contents Editor’s Note Letters To The Editor Back2Basics HVAC Challenge Case In Point Commissioning Efficiency Incentives HydroTech Building Automation Energy Wiz HVACR Designer Tips Notre Dame Tackles the Heat State Of The Arts Time For A Transplant? Project Delivery: What Can IPD Do For You? Issues & Events Computers & Software Products Application Checklist Glossary Classifieds Advertiser Index Tomorrow’s Engineer

Engineered Systems - June 2008

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