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DuctSox Fabric Ductwork installed in Sports Arena

Case Study

Cedar Rapids School

Cedar Rapids, Iowa

School District’s Geothermal/Heat Pump/ Fabric Duct Design Serves as Role Model HVAC Retrofit

Engineer’s design records utility bill savings of 60 to 65-cents/s.f. versus the $1/s.f. Annual operational costs for conventional system it replaces. Cedar Rapids, IA -- The Cedar Rapids Community School District’s (CRCSD) long term mission of energy-efficient HVAC building retrofits will save taxpayers millions of dollars in long term energy savings, but also provide optimal learning environments with unprecedented air comfort.

Annual Operational Savings

The state-of-the-art HVAC design by consulting engineering firm, Shive- Hattery Architecture & Engineering, Iowa City, Iowa, uses geothermal technology facilitated by water source heat pumps, energy-recovery outdoor air equipment and fabric ductwork in larger spaces. Middle School fifteen years ago. The successful design was later used in the HVAC retrofits of the remaining five middle schools, Truman and Hiawatha Elementary Schools, Thomas Jefferson and Kennedy High School, and most recently at George Washington High School. The design was first implemented in the HVAC retrofit of Roosevelt Washington’s results are still being tabulated. However, the three previous geothermal school retrofits have proven to be 30-40% more efficient than the original systems, according to Tim Fehr, P.E., Principal, Shive-Hattery, who progressively made the commitment to “use geothermal on every future school HVAC retrofit project.”

DuctSox Fabric Innovations

Truman’s original geothermal concept remains state-of-the-art today, although Shive-Hattery does tweak the design when including innovations introduced on the market such as DuctSox Custom Airflow Dispersion Systems. Truman’s open architectural ceiling areas used fabric duct manufactured by DuctSox, Dubuque, Iowa.

Fabric duct reduces ventilation material/installation costs and fast- tracks installation time by 60% to assure work completion during a short two-month summer recess. Shive-Hattery specifies fabric duct more frequently today, but now incorporates the industry’s latest innovations such as linear L-vents for indoor air comfort, custom colors to match school colors, in- duct tensioning systems for 24/7 inflated aesthetic appearance and other improvements.

Washington’s design takes advantage of DuctSox fabric systems many innovations with the use of a custom Warriors red color to match school colors, linear L-vents for draft-less air distribution, and the Internal Hoop System (IHS), which maintains an inflated appearance even when the air handler is off.

Keeping an inflated appearance and eliminating the distraction and noise of roll-outs during air handler startup was a game-changer and encouraged more fabric duct use than the past retrofitted buildings, according to CRCSD’s buildings and grounds manager. Fabric is also a good retrofit choice because double-wall insulated round metal duct is 85% heavier for contractors to handle. Also, metal typically requires painting or coatings, and is very labor-intensive when connecting seams or tightly threading through bar joists of open architectural ceilings, according to Fehr. While metal duct is difficult to remove and is expensively outsourced for cleaning in place, CRCSD’s in-house staff has a periodic schedule of cleaning fabric duct runs to provide optimal IAQ, which requires approximately a half- day to disassemble, commercially launder and reassemble. Another important factor in the CRCSD’s post-retrofits energy efficiency is the building automation system. The CRCSD also went the extra mile with their schools’ control systems realizing that extensive monitoring and control points create routines and programs that optimize total energy efficient. According to Fehr.

Kleinsmith’s in-house staff has a periodic schedule of cleaning fabric duct runs to provide optimal IAQ, which requires approximately a half-day to disassemble, commercially launder and reassemble. Another important factor in the CRCSD’s post-retrofits energy efficiency is the building automation system. The CRCSD also went the extra mile with their schools’ control systems realizing that extensive monitoring and control points create routines and programs that optimize total energy efficiency. According to Fehr. Future CRCSD school building HVAC retrofits will continue to deliver impressive energy savings well into the 21st Century using the Shive-Hattery geothermal design that’s still cutting-edge today.