Researchers, government agencies, and roofing manufacturers from around the world gathered in Berkeley last month (July 28-29, 2011) to discuss the latest research on cool roofs. These solar reflective materials reduce energy use, and help cool the planet by reflecting sunlight to outer space. Their use has begun to soar in markets around the world thanks to their economic and environmental benefits.
The International Workshop on Advances in Cool Roof Research was organized by the Heat Island Group of Lawrence Berkeley National Laboratory (Berkeley Lab), and by representatives of Concordia University, Oak Ridge National Laboratory, and the U.S. Department of Energy.
One focus of the workshop was understanding how roof materials age, including how quickly their ability to reflect sunlight changes, and how to best simulate this natural aging with accelerated laboratory processes under development at Berkeley Lab and at Oak Ridge National Laboratory.
Currently, the solar reflectance of a cool roof is rated after three-year of natural exposure in three different US climate zones, as required by the U.S. Cool Roof Rating Council. Developing accelerated aging test protocols is important to expedite the introduction of new cool roof products to market.
Meeting attendees also discussed how to incorporate cool roof requirements in building codes, and how to develop internationally recognized standard for natural and accelerated aging of roofing materials.
Marc LaFrance, Manager for Building Envelope and Windows R&D programs at the U.S. Department of Energy in the Office of Building Technology, welcomed participants, especially international visitors who traveled a long way to be in Berkeley, by audio feed from Washington D.C. He urged the group to work to develop accelerated aging test protocols that provide results faster than the current three-year standard for natural exposure.
Ashok Gadgil, Director of Berkeley Lab's Environmental Energy Technologies Division also welcomed the participants with an overview of EETD's research and a brief description of the Lab's current project of installing cool roof shingles on one of its major national user research facilities, the Advanced Light Source.
Art Rosenfeld, Distinguished Scientist Emeritus at Berkeley Lab, and former California Energy Commissioner, delivered a noontime Thursday talk showcasing the growing installation of cool roofs around the globe. He discussed recent Berkeley Lab research quantifying the capacity of cool roofs to cool the earth's atmosphere. "If we whitened all possible urban roofs worldwide," he points out, "it would be equivalent to removing the carbon dioxide emissions of 300 million cars for 20 years." Or in different terms, it offsets the emissions of 500 medium-sized coal-fired power plants.
Ronnen Levinson discussed the quantitative energy, climate and economic benefits of cool roofs. Dev Millstein presented his climate simulation studies to better understand the potential impact of cool roofs on the Earth's climate. Berkeley Lab researchers Mohamad Sleiman and Hugo Destaillats presented version 1.0 of their accelerated aging protocols, that combines soiling and weathering cycles and mimics well in 3 days only the changes in solar reflectance exhibited by 3 year naturally exposed roof samples.
A second day of presentations highlighted the growing international standardization and use of cool roof materials in the European Union, Japan, Australia and India. In another session, presenters provided a U.S. perspective on the influence of policies and codes on the adoption of cool roofs. Kurt Shickman, Executive Director of the Global Cool Cities Alliance, described his organization's efforts to promote cool buildings and cities globally, to reduce energy use and the urban heat island, and to mitigate the effects of climate change. Doug Davenport of Berkeley Lab described the San Jose Cool City Pilot project, a partnership between the city, Berkeley Lab, the Global Cool Cities Alliance and the U.S. Environmental Protection Agency.
Peter Turnbull, Principal Program Manager of Commercial Buildings and Zero Net Energy Program Manager at Pacific Gas and Electric, discussed the lessons learned on how to diffuse this new technology effectively though his company's northern California service area, and how their experience might be used by other utilities.