Fabric Duct More Efficient than Metal, Study Says

February 1st, 2012 → 11:37 pm @ // No Comments

Information all Los Angeles County Air Conditioning companies should know.

Mechanical engineers always suspected that fabric HVAC dutwork is more energy efficient than its meal duct counterpart, but now three members of the Iowa State University’s Mechanical Engineering Department have proven an overwhelming 24.5-percent efficiency differential.

The 10-month-long study, “Thermal Comparison Between Ceiling Diffusers and Fabric Ductwork Diffusers for Green Buildings” proved fabric duct heats rooms faster and more uniformly to satisfy temperature set points versus metal duct/diffusers, which results in reduced mechanical equipment runtime, thus saving energy in the process.

Thermal Air Conditioning provides you with the link to view this study which is now available free at www3.me.iastate.edu/bglab. It has also been published in Energy and Building Magazine, New York, an international journal of research applied to energy efficiency in the built environment.

The majority of its funding came from the National Science Foundation, Arlington, Va., and the Iowa State Institute for Physical Research and Technology, the latter which fosters the development of green technologies, such as fabric ductwork difusion.

The study used computation fluid dynamics (CFD) analytics in an 8x8x8-foot room with a ceiling-mounted return air vent, which is a typical commercial office space heating configuration. CFD modeling analyzed the airflow of a typical 1×1-foot metal ceiling supply fixture with a four-way diffusion pattern. Then compared it to the performance of an eight-foot-long, six-inch-diameter ceiling suspended fabric supply duct with seven pairs of one-inch-diameter air dispersion orifices spaced one-foot apart.

“Ductwork system efficiency tends to take a secondary importance to mechanical equipment efficiencies in project specifications, therefore we have now provide engineers with the data that will make air distribution more efficient as well,” said Micahel G. Olsen, Ph. D, an associate professor of mechanical engineering, who conducted the project along with Iowa State University mechanical engineering department colleagues, Baskar Ganapathysubramanian, Ph.D., assistant professor; and Ph.D. candidate/graduate assistant, Anthony Fontanini.
While various post-study phases are still being completed, the authors are certain of a slim +/-2.5-percent margin of error and that the same 24.5-percent efficiency can be achieved in larger spaces such as big box retailers, warehouses and other commercial/industrial buildings, according to Ganapathysubramanian.

“This analysis is used to construct metrics on efficiency,” said Ganapathysubramanian. “A number of different flow rates are examined to determine the performance over a range of operating conditions. Transient finite volume simulations consisted of over 13 million degrees of freedom for over 10,000 time steps. The simulations utilized HPC (High Performance Computing) for the large scale analysis.

As always, Thermal Air Conditioning thanks you for reading.


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