Review of bio-based phase change materials as passive thermal storage in buildings

Phase change materials (PCMs) have the potential to significantly decrease space conditioning loads and associated carbon emissions when integrated into a building. If PCMs with low embodied carbon are utilized, emissions associated with building operation can be reduced further (when compared to market-dominating paraffinic PCMs). For these reasons, research has been emerging on bio-based PCMs, such as animal- and/or plant-based oils, fatty acids, or combinations of these, in recent years. This study provides a comprehensive review of the thermophysical properties, building integration techniques, and lifetime impacts of bio-based PCMs, including barriers limiting their usage and potential areas for future research. PCMs of different thicknesses have minimized conditioning loads most in moderate climates, compared to extreme cold or warm regions. The results of this review also show that primary use bio-based PCMs may have similar or greater lifecycle carbon emissions when compared to paraffins; however, recycled, secondary use bio-PCMs may minimize total carbon emissions and is an area that necessitates future research.