"With this new research project, and working closely with DOE’s Oak Ridge and Lawrence Berkeley National Laboratories, we are looking to push performance boundaries, which could ultimately result in an entirely new polymer technology for elastomeric roof coatings,” said William Jackson, global research and development leader for Dow Building and Construction. “We’re excited to be part of this important research project that has the potential to greatly increase cool roof adoption rates and reduce our nation’s energy usage and environmental footprint.”
Cool roof coatings are a cost-effective and relatively non-intrusive means of improving the energy efficiency of existing buildings, which offer over 20 billion square feet of commercial roofing space subject to retrofit in the U.S. today. DOE estimates that replacing or resurfacing conventional roofing materials with these improved reflective elastomeric roof coatings (ERCs) can reduce a commercial building’s annual air conditioning energy use by up to 25 percent, an improvement from up to 15 percent savings of existing ERCs, and decrease annual CO2 emission by five metric tons for every 10,000 square feet of commercial roof area. These ERCs also potentially offer a one-time offset of 150 metric tons of CO2 per 10,000 square feet of cool roof via “global cooling” (negative radiative forcing). Energy savings are highly variable based on levels of installed insulation, climate and other related factors. DOE has a calculator to help building owners determine the potential savings of their buildings, which can be found at www.roofcalc.com.
Current standards require that after three years of exposure to the elements, cool roofs retain a solar reflectance of at least 55 percent. The charge of the CRADA is to develop new technologies that would enable cool roof manufacturers to meet a standard of 75 percent solar reflectance after five years, which would increase cool roof energy savings by over 50 percent compared to current ERCs.
Dow and ORNL, in partnership with Lawrence Berkeley National Laboratory (LBNL), will focus on technologies to improve the long-term resistance to dirt pick up and microbial growth on white elastomeric roof coatings. The aim of this program is to improve retention of solar reflectance using newly developed and accelerated testing protocols for faster commercialization.
As part of the CRADA, Dow and ORNL/LBNL also intend to develop accelerated weatherization testing protocols that speed commercialization, and conduct studies to quantify the performance of the new cool roof products. This work would potentially allow DOE to propose new standards for cool roof performance. The stated outcome of the CRADA is to commercialize the next generation of polymers for roof coatings to save energy in new and existing buildings, and to advance a predictive accelerated aging/dirt pickup testing program for cool roof coatings.