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N E W S NEWS Y O U N E E D , YOU NEED, P R O D U C T S PRODUCTS Y O U W A N T YOU WANT Learn more about featured products at HVACPproducts.com/ market HVACPproducts.com/subscribe alternatives when accounting for VRF's expedited labor advantages. Operating expenses are expected to be approximately 30 percent lower while providing zoned temperature control for occupants versus the previous system. "We've noticed a definite indoor comfort improve- ment with the VRF system," said David Harrison, executive vice president of TSB. The building's original three air handlers were replaced with 32 Mitsubishi VRF-based fan coil units in zones fed by two branch circuit controllers per floor. Eighty-percent of the building's original supply ductwork was re-used for air distribution at a great savings. The VRF equipment's sizing was determined by the building's peak north side heating load. Sain and Wilkerson's VRF calculations were assisted by Andy St. John, commercial sales manager at Mitsubishi distributor Robert Madden Co. and verified by Power Systems' in-house computer modeling. SUPPORT FOR CUTTING-EDGE TECHNOLOGY Because it was Air Dynamics' first major VRF project, Sain was comprehensive in managing and installing the project. He sent his installation and service crew to a Robert Madden Co.-sponsored VRF school in prepara- tion. Sain also wanted to find the highest quality mount- ing system for the rooftop condensers and discovered Big Foot Systems rooftop equipment mounts, also avail- able through RectorSeal. Instead of the conventional poured rooftop concrete pads and the roofing costs associated with them, Sain specified Big Foot Systems, which are tubular, corrosion-resistant, hot-dipped gal- vanized modular steel support frames. The frames were designed by RectorSeal's in-house engineering team and assembled onsite in various configurations by Air Dynamics' crew to custom fit the condensers. While the Big Foot system is an aesthetic and functional consideration, Sain recommended them also for superior sound and vibration attenuation properties. Previously, he had not been completely satisfied with noise abatement attempts of previous mechanical rooftop systems set on I-beams, even when used with anti-vibration pads. The mounting system features adjustable legs and 12-by-12-inch square anti-vibration nylon feet. When the building is re-roofed someday, roofing can be replaced underneath one leg at a time while the units and piping stay connected and functional. The system also includes nylon-footed "H"-shaped stands for the lineset ducting. Sain found the mount- ing systems' under-unit access very convenient for expedited refrigeration and electrical hookups. The system's conduciveness to attaching appendages, such as electrical conduit with common hardware clamps, encouraged Sain to innovatively support each condensing unit's electrical disconnect boxes to the mounting frame. "The mounting system is costlier in materials than I-beams, but it's really an even trade-off because in- stallation labor is cut by more than half and it looks so much better," said Sain, who has more than 45 years of experience in the HVAC industry. Another energy savings built into the design was a 10-ton, 2,000-cfm dedicated outdoor air system by Desert Aire, supplied by Direct Expansion Systems. Previously, space humidity was controlled strictly with air conditioning, which on hot West Texas summer days is inefficient and costly in electricity. The DOAS provides outdoor air dehumidification and condition- ing, but also recovers 95 percent exhaust air energy. The unit also includes an integral back-up gas-fired heater for additional heating capacity. To support Sain's request for VRF, Wilkerson performed a cost analysis comparing it to conventional chiller, rooftop DX and split DX systems and found its higher capital equipment costs were offset by a reduction in labor and installation expenses. The real advantage Wilkerson found in the VRF installation was minimal downtime or tenant space disruption. "My cost comparison analysis found that all the HVAC methodology choices for the TSB, including VRF, were within a few percentage points of each other in price," Wilkerson said. Both Sain and Wilkerson plan more VRF system de- signs in the future and predict VRF will become an im- portant factor in U.S. HVAC design as contractors gain more installation experience and costs are reduced due to volume and experience. CHECK OR CIRCLE #164 The RectorSeal Corp. is a manufacturer of chemical and specialty products designed for the plumbing, heating, air conditioning, electrical and construction industries. For more information, visit www.rectorseal.com, email marketing@rectorseal.com or call 800-231-3345. The key players in the Texas State Bank building HVAC retrofi t are, from left: Robert Hatfi eld, owner Bill Caldwell Electric; Cecil Sain, president, Air Dynamics Inc.; Jeremy Harrison, vice president, Harrison Roofi ng; Paul Wilkerson, owner, Power Systems and David E. Harrison, vice president, Texas State Bank. HVACPproducts.com Summer 2014 \ HVAC & Plumbing Product News 21 F d H A P 0 6 1 4 - 0 1 - 2 8 . i n d d 2 1 FdHAP0614-01-28.indd 21 7 / 2 / 1 4 1 0 : 5 8 A M 7/2/14 10:58 AM