A team of Metal Construction Association members, contractors and manufacturers say they have developed a new retrofit roofing concept that merges existing technologies into an integrated metal roof system that can improve energy efficiency and lower energy demands in buildings.
Known as a fully-integrated retrofit metal roof system, the concept is described as a “holistically designed” metal retrofit roofing system that creates an air space by adding structural subframing atop the existing roof, followed by installation of a new cool metal roof over the assembly, the Metal Construction Association (MCA) says.
Metal Construction Association
Within the air space, the installation will house high-performance insulation, solar water heating, and solar thermal air cooling systems. The surface of the retrofitted roof enables solar generated electricity and rainwater collection systems to be installed on the topside of the new metal roof.
The project team also included members of the U.S. Dept. of Energy's Oak Ridge National Laboratories (ORNL), Oak Ridge, TN, where metal roof components have been tested and proven energy efficient, MCA said.
Cool metal roofs are produced by applying solar-reflective coatings on metal to be used in roofing, typically by means of the coil-coating process in large-scale, automated industrial finishing operations. Field-applied, reflective “cool-roof” coatings also can be used for roof maintenance and restoration.
DOD Project to Demonstrate Roof System’s Performance
The Department of Defense's Environmental Security Technology Certification Program (ESTCP) has awarded MCA a grant for a 20-month project demonstrating the performance of the integrated retrofit system, which will be installed on a U.S. Department of Defense building at a U.S. Air Force base in Texas. Preparations for the installation are now in progress; when it is complete and the building instrumented, the system will be monitored for its impact on energy use, water use and overall savings, MCA said.
MCA said the DOD project will provide substantiated research data and cost savings that meet or exceed the department’s stated directive to reduce energy consumption in all forms.
“The expected energy savings from these technologies will improve the energy efficiency of the building and lower the electrical energy demand from the grid and on fossil fuels for water heating and space conditioning,” MCA said. “In addition, the incorporation of a rainwater harvesting system will reduce the demand for fresh water.” MCA said these improvements also will enhance DOD’s capability to obtain U.S. Green Building Council LEED certification on new and retrofit projects.
The association said it is anticipated that the high-performance roofing system will deliver approximately 6 kilowatt hours and 6 to 12 KWH-T (kilowatt thermal equivalent) per square foot of installed area, depending upon location, solar-array orientation and thermal system loads.
Members of the MCA-supported team will manage the project installation. Robert Scichili Associates Inc., Richardson, Texas, will coordinate information updates between the ESTCP, MCA and the building site. Paramount Metal Systems, Little Rock, Ark., will oversee all design and construction management, procure materials for the entire roof assembly, and act as liaison with Dawn Solar Inc. Brentwood, N.H., for all solar-related equipment, purchasing and installation.
A mock-up of the integrated system will also be displayed at the METALCON International show, where an education session about the technology titled "Integrating Building Envelope Roof Technologies" will also be presented on Wednesday, Oct. 12. Presenting the program will be Mark James, vice chair of the MCA Retrofit Council and vice president of sales and marketing for Roof Hugger Inc., Odessa, Fla., and Scott Kriner, MCA technical director and President of Green Metal Consulting Inc., Macungie, PA.
METALCON is sponsored by the MCA, and is scheduled for Oct. 11 -13 at the Georgia World Congress Center in Atlanta. More information: www.metalcon.com.
Project Marks Further Step in Roof-System R&D
Rick Perry, MCA’s technical and research manager, said the DOD project applies some of the findings from a study carried out by the Department of Energy’s Oak Ridge National Laboratory and MCA, involving “dynamic” roof assemblies that employ combinations of retrofit metal panels, integrated with photovoltaic laminates and a phase-change material heat sink. That study was described in a Durability + Design story in October 2010; see Subtraction by Addition: Multiple Parts Equal One Cool Roof System.
“The DOD project uses some of the information from the DOE/MCA study, but take it much, much further,” Perry told Durability + Design. “The metal roof is an important part of the integrated metal roof system in the DOD proposal, but this is a fully-integrated retrofit metal roof system.”