A novel photovoltaic/thermal (PVT) system using nano-enhanced micro-encapsulated PCM slurry for steam production: A numerical study

As industries reliant on steam-based processes strive to reduce fossil fuel consumption and carbon emissions, interest in renewable technologies, particularly photovoltaic/thermal (PVT) systems that generate both thermal and electrical energy, is increasing. However, the limited thermal performance of PVT systems remains a key barrier. Traditional working fluids, such as water, nanofluids, and phase change material (PCM) slurries, exhibit low thermal conductivity, poor temperature regulation, and inefficient heat storage. To address these issues, a novel working fluid incorporating graphene oxide (GO) nanoparticles into microencapsulated PCM (MPCM) slurry is proposed. The integration of GO nanoparticles not only enhances the dispersion stability of the MPCM slurry but also significantly increases its thermal conductivity, leading to improved heat dissipation from PV cells. A comprehensive CFD investigation is conducted using ANSYS Fluent 2021, employing an Eulerian–Eulerian multiphase model to simulate the three-phase flow. In this model, water serves as the primary phase, while GO nanoparticles and MPCM function as secondary dispersed phases. The results demonstrate that increasing the GO volume fraction from 0 to 0.005 reduces average PV cell temperatures by up to 5°C at 40°C. Additionally, the nano-enhanced MPCM slurry achieves a thermal efficiency of 88.1 % and an electrical efficiency of 10.3 %. It is also found that using MPCM slurry as the working fluid, a 15 % volume fraction of MPCM with a melting point of 40°C achieves the highest thermal efficiency of 90.1 %, outperforming water by 20.1 % and surpassing previous studies on MPCM slurry and nanofluids. © 2025 The Author(s)