Experimental and Numerical Investigation of a Bio-Based Nano-Enhanced Phase Change Material Integrated within a Thermal Energy Storage System: Early Results

Global energy demand and the limitations of fossil fuels have accelerated interest in renewable energy and efficient storage technologies. Solar thermal systems paired with latent heat thermal energy storage (LHTES) offer a promising solution, relying on phase change materials (PCMs) to store and release heat during phase transitions. However, conventional PCMs such as paraffins exhibit low thermal conductivity, which restricts system efficiency. The use of nanoparticles has been studied as an effective approach to enhance heat transfer. This study presents a preliminary evaluation of the performance of a commercial organic fatty acid PCM and its nanoenhanced counterpart incorporating 4 wt.% graphene nanoplatelets (GNPs). Both materials were tested experimentally and numerically within a small lab-scale domestic hot water storage tank. Results show that the nano -PCM accelerates melting and solidification, reducing melting time by 6 min and increasing the discharge temperature by about 1.3 °C compared with pure PCM. CFD simulations showed good agreement with the experimental results. Overall, the incorporation of GNPs markedly improves LHTES performance, enabling more efficient and reliable solar thermal systems.