Energy Efficient Phase Change Materials (PCM) Insulation
Nicholas Josefik | USACE ERDC-CERL
This project will demonstrate the advantages of blown-in phase change materials (PCM) based insulation to mitigate energy loss in building envelopes. The technology addresses the problem faced by the Department of Defense (DoD) to reduce energy intensity (BTUs per square foot) by 3% per year or 30% overall by 2015 from the 2003 baseline, as per the Energy Independence and Security Act of 2007. Under DoD's High Priority Performance Goals, the interim target is an 18% reduction by the end of 2011. Energy monitoring instrumentation will be installed on a selected building at Fort Bragg, North Carolina, and the efficacy of the current fiberglass insulation will be monitored for 1 year. Cellulose insulation with PCM will then be blown into the attic just above the drop ceiling, and the energy usage will again be monitored for 1 year, and compared.
The PCM insulation to be demonstrated is made by combining cellulose insulation with hard shell polymer microcapsules (2-20 microns in diameter) that contain organic fatty acids and fatty acid esters as core materials. The core materials change phase from solid to a liquid or semi-liquid to prevent excessive heat flow and maintain comfortable temperatures; they exhibit a "thermal mass effect," i.e., capacity to store energy as latent heat. On very hot days the PCM will prevent outside heat from entering the building by changing phase to soak up the extra heat, thus reducing the cooling load. On cold days, the PCM helps to conserve heat energy escaping into the walls, by storing that energy as "latent heat." The latent heat is released back into the building as "sensible heat" when the temperature drops at night. This project will attempt to show that significantly less energy is required to maintain comfortable temperatures using the PCM insulation in attics, compared to the currently used fiberglass insulation.
The innovative PCM-based insulation technology is expected to enhance energy efficiency in heating and cooling buildings in moderate climates by reducing excess sensible heat in the summer and reducing heat loss in the winter. The anticipated cost of this technology is 40% greater than the cost of standard insulation; however, the technology is expected to save 30% of the annual cost of energy for heating and cooling. (Anticipated Project Completion - 2014)