C42 -- Operational and Lifecycle Carbon Assessment of Building-Integrated Phase Change Materials

Phase change materials (PCMs), when integrated into a building, have the potential to store thermal energy and delay its release into a conditioned space, reducing peak solar loads in the cooling season, and prolonging the time during which passive solar heating can occur during the heating season. As such, PCMs can reduce conditioning-related operational emissions. To date, limited research has been conducted to quantify these operational emissions reductions, alongside the associated embodied emissions of PCMs. The objective of this study was to predict the emissions payback period associated with PCMs installed into the wallboard of a house using EnergyPlus. The analysis considered over 30 geographic locations across Canada and the United States located in various ASHRAE climate zones, and with different electricity grid emissions intensity values. It was found that, in nearly all locations across Canada and the United States, the emissions payback period would be less than 20 years due to the installation of PCM. Lower emissions payback period values (6 years or less) occurred with natural gas space heating, except in cases wherein the city electricity grid intensity contributed greater emissions due to space conditioning than with natural gas. In contrast, in locations such as Manitoba and Quebec, Canada, with low emissions intensity electricity grids, the emissions payback periods were found to be up to 190 years. The results indicate that PCM could be used as a transitional technology to reduce the operational emissions associated with buildings during the gradual transition to lower carbon intensity space conditioning equipment.