Paraffin As a Phase Change Material to Improve Building Performance: An Overview of Applications and Thermal Conductivity Enhancement Techniques

Abstract

In recent years, phase change materials (PCMs) have increasingly received attention in different thermal energy storage and management fields. In the building sector, paraffin as a phase change material (PPCM) has been introduced as an efficient PCM incorporated in a building envelope, which showed remarkable results. However, the poor thermal conductivity of PPCM is still the topmost drawback in experimental and numerical investigations. In this paper, a general assessment of paraffins, their common uses and applications, have been presented with a particular focus on their potential in building envelope applications. Moreover, the general and desired properties of PPCM are highlighted and evaluated. The primary practical limitation of PPCM of poor thermal conductivity and their effect on PPCM performance is presented and discussed. Correspondingly, the popular techniques applied to improve the poor thermal conductivity are presented and discussed in four categories: the dispersion of nanoparticles, expanded graphite, metallic foam, and extended surfaces technique (fins). All in all, the analysed research works indicated that PPCM based building envelope applications could remarkably improve the thermal performance of buildings in terms of thermal load reduction, energy-saving and thermal comfort. Furthermore, the adoption of enhancement techniques is essential to improve the thermal performance of PPCM in building applications for better utilisation. This review provides a clear vision for the newcomers and interested parties about the main application aspects of PPCM in the building sector for further investigations towards technology commercialisation.