Engineered Systems - March 2008 - (Page 50)

HVAC Here is why the CESVA SC-160 or SC-310 Meter is essential for your job: The Modern Unit Ventilator lems, a prime one previously mentioned (leaky dampers), and all of them easily solvable by using F/BP. Years ago, some engineers felt there was a significant benefit to using a blow-through coil configuration rather than draw-through. Blow-through mixed the air before it came to the coil and minimized stratification (another prime freeze cause). However, a bigger freeze cause is valve control of the hot water coil. In a UWUV, the coil is 5 or 6 ft long and fed from one end. The room thermostat control is based on average temperature, and it was not uncommon to see temperature differences of 30°F or 40° from one end of the coil to the other. Maintenance. A big plus for UVs vs. a central system such as VAV is that an outage will only affect one room, not the whole building. However, a big negative is that UWUVs are hard to work on when things do need maintenance. All work has to be done either kneeling or lying on the floor. The end compartments of UWUVs will get very congested with piping and controllers, making that equipment hard to get to (this is another area where F/BP offers advantages with fewer devices to pipe up). The VUV tends to have a lot more room for piping and controls, and all work can be done by one mechanic standing on the floor. 12/13/07 1:06:57 PM 800-224-3813 FREE INFO: 17 ES01084Scantek.indd 1 NO DUCT TAPE KLO-SHURE® INSULATION COUPLINGS • • • • • • • Installs 60% faster Supports tubing and secures insulation Superior vapor barrier Eliminates insulation compression Improved finish – no tape, no glue Reduced material cost Meets the 25/50 flame spread/smoke developed index Contact us today to request your FREE product catalog, and learn how well Klo-Shure Insulation Couplings can work for your next project! CONCLUSION The UV still has a place in school design, but not the way it was done 20 years ago. The UV should be considered when doing renovations of existing UV schools. The UV should be strongly considered for buildings that have insufficient headroom for central air handler ductwork. And when properly applied, the UV can be less expensive to build, less expensive to operate and easier to maintain than other options, without compromising IAQ, occupant comfort, or humidity control. ES 1-800-839-0891 or www.klo-shure.com Durkin is a principal at Durkin & Villalta Partners Engineering (Indianapolis). Reach him at tdurkin@ dvpe.net. Partington is vice president of Temspec Inc. (Toronto). Reach him at bpartington@ temspec.com. FREE INFO: 75 50 En gi neer ed S y stem s March 2008 http://www.scantekinc.com http://www.scantekinc.com http://www.klo-shure.com

Table of Contents Feed for the Digital Edition of Engineered Systems - March 2008

Engineered Systems - March 2008 Contents Editor’s Note Back2Basics HVAC Challenge Case In Point Commissioning Building Automation Energy Wiz HVACR Designer Tips Application Checklist Exemplary Design = Elementary Success The Modern Unit Ventilator On A Mission VAV Systems And Green Design – Part II Issues & Events Products Glossary Classifieds Advertiser Index Tomorrow’s Engineer

Engineered Systems - March 2008

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