Collaborative Research, Development, and Patent Licensing for an Energy-Saving Roofing System

Abstract

This paper describes the process and preliminary results of a collaborative research and development project for an energy-saving ventilating roofing tile system intended for market introduction. The project also served to apply an interdisciplinary design approach to the fields of architecture and civil engineering similar to that used in many high-tech industries. I began the project seeking to develop a marketable high slope roofing system having: (a) an internal ventilation system to mitigate solar heat transfer, (b) a partial composition of recycled material, (c) durability and resistance to stresses including transport, impact, and natural forces (freeze/thaw, fire, insects, precipitation, earthquake, etc.). Interlocking roofing tile geometries were explored producing a series of contiguous channels running from eave to ridge. These geometries suggested using non-conventional roofing materials. Asst. Professor Gregor Fischer, Univ. of Hawaii at Manoa (UHM), Dept. of Civil and Environmental Engineering, who specializes in Engineered Cementitious Composites (ECC) and I discussed the project, and we decided to collaborate. We evaluated the potential of ECC for forming the roof tiles. ECC appeared promising for this application as it: (a) can be molded using common mass-production methods, (b) can be made with recycled or waste materials, (c) has a high strength-to-weight ratio, and can withstand bending stress without steel reinforcement, (d) is crack and weather resistant, (e) is fire resistive, (f) can be formed with various shapes, textures, and colors. Computer and physical models were used to achieve a design synthesizing form, material, and function in the system. This synthesis was achieved due to our combined expertise in construction methods, building systems, material science, and structural analysis. Prototype tiles were molded of ECC, and were evaluated for dimensional tolerance and impact and bending stress resistance. To secure intellectual property protection for the ventilating roofing system, we conducted a patent search and co-authored a Provisional Patent Application which was filed with the U.S. Patent and Trademark Office through UHM's Office of Technology Transfer and Economic Development (OTTED). An OTTED development award allowed thermal testing of the system. As of this writing, testing is starting and is scheduled to conclude in June 2005. Test results hope to show that the ventilating roofing system will reduce heat transfer from the roof to underlying interior spaces vs. existing methods. Prototype molding techniques were successful, and these appear adaptable to roof tile industry practices. Due to the promising indicators of commercial viability, OTTED has indicated interest in filing a utility patent on the invention, and negotiating patent licenses with manufacturers.