Air leaks in buildings contribute to energy use by allowing uncontrolled airflow between conditioned and unconditioned spaces. Current methods for tightening building shells have relied primarily on manual sealing methods that are labor intensive and often insufficient, particularly in retrofit applications. WCEC is testing an aerosol envelope sealing process, AeroBarrier, to improve sealing effectiveness, reduce labor costs, and improve the consistency of installation. AeroBarrier was originally developed by WCEC with funding from the California Energy Commission and U.S. Department of Energy. This past year, the WCEC demonstrated AeroBarrier in both commercial buildings and new single-family homes.
The results presented are expected to facilitate the adoption of the aerosol sealing method for other DoD installations by providing a number of demonstrations on multiple building types and in multiple climate zones. Prior work in residential homes has demonstrated excellent results showing the ability to seal 80% of the building leakage in less than two hours with prototype equipment. Very few retrofit demonstrations have been performed which was the focus of this project. These demonstrations validated the performance of the sealing technology as an effective solution for retrofit installations.
This project demonstrated that the aerosol envelope sealing technology is very effective at sealing building leakage on DoD facilities. Ultimately, over 75,000 CFM at 75 Pa was sealed over the sixteen demonstrations cutting the air leakage of the buildings in half. presents the overall percent air leakage reduction for each demonstration. The most successful demonstration sealed 80% of the building leakage and three of the demonstrations brought the buildings to within the USACE specification for envelope leakage. This was impressive considering two of these buildings were in poor condition and scheduled for demolition.
Durability testing was performed to assess the strength and longevity of the seals created using the aerosol sealing process. Seals were created under different humidity conditions to determine the sensitivity of seal strength to this parameter. Multiple tests were conducted on seals formed on test plates in the laboratory, including pressure cycling at medium and low pressures, temperature cycling at medium pressure, and holding high pressure for one hour.
In summary, there were no seal failures during the lab testing of seal durability in which the seals were subjected to pressures up to 5,000 Pa (equivalaent to a wind speed of more than 200 miles per hour). There was a gradual increase in leakage rates when subjected to prolonged pressures above 800 Pa. Cyclic tests at more reasonable pressures of 100 Pa showed that after 1,900 pressure cycles the overall change in leakage flow between the first and last 100 cycles was 0.067 scfm for the six sealed leaks tested. This translates to an increase in leakage area of approximately 0.004 in2. For six sealed leaks each measuring about 1.2 in2, this represents an overall increase of less than 0.1% in the sealed leakage area, indicating very little change over the course of the testing. You can find additional durability testing information here
The Western Cooling Efficiency Center (WCEC) is an authoritative and objective research center at the UC Davis Energy and Efficiency Institute that accelerates the development and commercialization of efficient heating, cooling, and energy distribution solutions. Their work is increasingly important as energy policies in the U.S. and California recognize the far-reaching implications of greenhouse gas emissions on our environment and changing climate. You can learn more about WCEC here
Working closely with manufacturers, policymakers and utilities, WCEC tests new and existing HVAC technologies in our laboratory. They also deploy real world demonstrations that provide objective technology evaluations of field performance. Their engineers recommend and implement performance improvements for the technologies tested.
HUMAN FACTORS & POLICY RESEARCH
WCEC understands that even game changing technologies face considerable barriers to adoption that include policy, market and human interaction. WCEC works with policymakers, supporting codes and standards that will save energy and promote new, efficient technologies. They also work closely with Utility partners, to evaluate technologies for market incentives, and in parallel, address human behavioral factors