A mock metal roof and attic assembly, designed to demonstrate Glenview, Ill.-based Metal Construction Association manufacturer member’s energy-efficient products, was built by University of Tennessee at Knoxville students and showcased at METALCON International last October in Tampa, Fla. Prior to the demonstration, a team of four senior engineering students from UTK—Ethan Herman, Adesanya Oldamilola, Steve Pionke and David Whittiker, directed by Dr. William Miller, adjunct professor at UTK and research engineer at Oak Ridge, Tenn.-based Oak Ridge National Laboratory’s Building Envelope Group—studied heat transfer and modeling software used in the construction industry. The work involved simulating the effect of infrared reflective pigments in painted metal roof panels that were offset mounted from the roof deck. Students determined the air space formed between the metal roof and deck allowed for natural convective cooling airflows that carry heat away from the attic plenum. The team compared it to a conventional direct nailed asphalt shingle roof having different solar reflectance levels. Simulations looked at different aspect ratios of the air space above the roof deck and different emissivity levels for radiant barriers placed in the attic. From these simulations, the students built the roof and attic display for MCA.
From the demonstration, a data acquisition system displayed temperatures of a metal roof and asphalt shingle roof while heated by infrared heat lamps. The display showed the effects of a cool paint system, above-sheathing ventilation and radiant barriers on roof deck and attic air temperatures. A scheme for recovering solar heat from the roof was designed into the display and was highlighted to show attendees the opportunity to use the roof’s solar heat to supplement whole space and process heating energy. For more information, visit www.metalcon.com.