Micro-/nano-encapsulated phase change materials: Revolutionising heat transfer fluids for solar energy applications
Oguzhan Kazaz, Nader Karimi, Manosh C. Paul
Abstract
Micro- and nano-encapsulated composite phase change material-based heat transfer fluids represent a promising advancement for solar energy systems by significantly enhancing heat transfer and thermal energy storage capabilities. This review addresses the critical limitations of conventional heat transfer fluids, such as low thermal conductivity and limited energy storage capacity, which hinder solar thermal system performance and efficiency. The integration of advanced encapsulated phase change materials is hypothesized to overcome these challenges by simultaneously augmenting thermal storage capacity and heat conduction, thus optimizing the overall solar system performance. This paper systematically reviews recent progress in the selection of phase change materials tailored for solar applications, innovative encapsulation techniques, and the development of micro- and nano-encapsulated composite fluids with improved thermophysical properties. Applications in various solar thermal systems are examined to highlight their practical potential. Key findings from experimental and theoretical studies demonstrate that these advanced composite materials and fluids can improve thermal conductivity by up to 471 % and enhance energy storage efficiency by 92 % compared to traditional materials and heat transfer fluids. Despite these promising results, challenges remain, including scalability of manufacturing processes, long-term thermal and chemical stability, and environmental sustainability of materials. The review emphasizes the need for further research focused on scalable production methods, durability testing, and eco-friendly material development. Overcoming these obstacles is essential to enable broader commercial adoption. Ultimately, these innovations hold the potential to significantly boost the cost-effectiveness, reliability, and sustainability of solar thermal technologies, contributing to a faster global transition toward renewable energy sources.