Evaluation of Phase Change Materials for Cooling in a Super-Insulated Passive House

• Main Author: Lauck, Jeffrey Stephen
• Format: Others
• Published: PDXScholar 2013
• Subjects: Dwellings > Insulation > Oregon > Portland > Case studies; Dwellings > Energy conservation > Oregon > Portland > Case studies; Dwellings > Heating and ventilation > Oregon > Portland > Case studies; Ecological houses > Oregon > Portland > Design and construction > Case studies; Construction Engineering; Engineering Science and Materials; Environmental Design; Natural Resources and Conservation
• Online Access: http://pdxscholar.library.pdx.edu/open_access_etds/1444; http://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=2443&context=open_access_etds

Due to factors such as rising energy costs, diminishing resources, and climate change, the demand for high performance buildings is on the rise. As a result, several new building standards have emerged including the Passive House Standard, a rigorous energy-use standard based on a super-insulated and very tightly sealed building envelope. The standard requires that that air infiltration is less than or equal to 0.6 air changes per hour at a 50 Pascal pressure difference, annual heating energy is less than or equal to 15kWh/m2, and total annual source energy is less than or equal to 120 kWh/m2. A common complaint about passive houses is that they tend to overheat. Prior research using simulation suggests that the use of Phase Change Materials (PCMs), which store heat as they melt and release heat as the freeze, can reduce the number of overheated hours and improve thermal comfort. In this study, an actual passive house duplex in Southeast Portland was thoroughly instrumented to monitor various air and surface temperatures. One unit contains 130kg of PCM while the other unit contains no PCM to serve as an experimental control. The performance of the PCM was evaluated through analysis of observed data and through additional simulation using an EnergyPlus model validated with observed data. The study found that installation of the PCM had a positive effect on thermal comfort, reducing the estimated overheated hours from about 400 to 200.