Novel multi-layer nano-modified PCM configuration for efficient thermal management of photovoltaic-thermal systems

Effective thermal management of photovoltaic (PV) systems is crucial for mitigating temperature-induced efficiency losses and enhancing overall performance. This study proposes a novel approach to address this challenge by employing multi-layer phase change materials (PCMs) with strategically degraded nanoparticle concentrations integrated into photovoltaic-thermal (PVT) systems. The transient heat-transfer dynamics, temperature distributions , and conversion efficiencies were numerically investigated for three configurations: a uniform single-layer nano-PCM, a two-layer nano-PCM with degraded concentrations, and a three-layer nano-PCM with degraded nanoparticle concentrations. Notably, the three-layer degraded configuration consistently outperformed other arrangements, maintaining PV temperatures up to 5 °C lower and electrical efficiencies up to 4 % higher over 100 min of operation. This configuration also achieved the highest thermal efficiency of 0.682, surpassing the single PCM case by 6.7 %. By combining multi-layer PCMs with degraded nanoparticle loadings, the proposed approach enabled more uniform heat distribution within the nano-PCM composite, overcoming the inherent limitation of decreasing thermal interaction between nanoparticles and PCM regions farther from the heat source observed in uniform nano-PCMs. The proposed approach for thermal management can significantly enhance the heat absorption, temperature regulation, and thermoelectric performance of PVT systems under continuous operation scenarios. • New approach using multi-layer nano-PCMs with degraded nanoparticle concentrations • Graphene nano-PCMs showed superior thermal regulation over alumina and copper. • Multi-layer nano-PCMs with graded configurations outperformed uniform configurations. • Degraded concentrations enable more uniform heat distribution within the nano-PCMs.