Athletic center aims high


In Oskaloosa, Iowa, William Penn University recently underwent the largest and greenest expansion in the private university's 135-year history. The project featured geothermal heating and cooling, fabric ductwork, energy recovery ventilators (ERVs), and advanced BAS. The recent additions help make the 155,000-sq-ft Penn Athletic Center (PAC) the most efficient building on campus. The green design qualified William Penn for a $340,000 incentive from MidAmerican Energy, the local utility.

Michael Vogt, project engineer for design/build mechanical contractor Cunningham Inc ., believes the combination of geothermal, fabric duct, and ERVs will earn points toward U.S. Green Building Council LEED certification. The fabric ductwork from DuctSox saved 60% in HVAC ductwork installation costs versus metal duct. The fabric duct also evenly distributes heating/cooling space temperatures, which leads to shorter, energy-saving mechanical equipment run times.


The PAC's gable roof, which rises 45 ft at its pinnacle, presented challenges to the design team. High ceilings are mandatory for sports complexes like the PAC, so an air distribution system with a high-throw capability was necessary. Although metal duct is capable of high throws, metal duct registers placed every 10 ft result in uneven throws. The Cunningham team installed two 290-ft runs of 48-in.-round TufTex, which was specified to have 3-in.-diameter high-throw orifices running the entire length.


“There's a noticeable difference between the air comfort in the PAC and other large athletic buildings with metal duct/register systems,” said Vogt. “Plus, the college saved tens of thousands of dollars in installation labor costs because lightweight fabric duct is so much faster and safer for workers to install in elevated places.”


The geothermal system supplies the ductwork for the PAC and the 55,000-sq-ft Musco Technology Center. The system conserves the most energy of any of the new systems. The athletic center's six 20-ton heat pumps continually receive 55-F water from a geothermal well field. The water is drawn to the two buildings by two 460-V, 25-hp pumps, which run through 25 miles of underground horizontal piping bored at 15, 30, and 45 ft. Varieties of smaller heat pumps are located throughout the facility to service the locker rooms, showers, offices, and exercise rooms. While the geothermal system handles the sensible heat load of the building, Vogt specified various ERV models to handle the latent heat load by recovering energy from the return air.


William Penn University's state-of-the-art design is expected to be a role model for other campus buildings nationwide that want to combine green and sustainable features with indoor air comfort and quality.


Information provided by DuctSox.



William Penn University in Oskaloosa, Iowa, underwent the largest green expansion project in the university's history. The project featured geothermal heating and cooling, fabric ductwork, energy recovery ventilators, and advanced BAS. The expansion project's highlights include:


  • Fabric ductwork that saved 60% in HVAC installation costs versus metal duct.

  • A geothermal system that supplies the ductwork for the PAC and the Musco Technology Center.

  • Six 20-ton heat pumps which receive 55-F water from the geothermal well field.

  • Water that draws to the two buildings by two 25-hp, 460-V pumps.

  • Installation of two 290-ft runs of 48-in-round TufTex, specified to have 3-in.-diameter high-throw orifices.

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