Thermoregulation of integrated photovoltaic panels with bio-based phase change materials

Resumo

Although photovoltaic (PV) technology has achieved significant advancements in harnessing irradiation to generate electricity, different questions remain open, especially regarding the adverse effects of high temperatures on the PV system. As the temperature of PV panels increases, their energy-conversion efficiency decreases, reducing the overall electricity production. High temperatures also accelerate the degradation of the PV panel, leading to shorter operational lifespans and higher maintenance costs. Hence, reducing the PV panel temperature throughout the day can prevent thermal degradation and increase its efficiency. In the present work, we numerically evaluate the thermal behavior of a PV system integrated with a phase change material (PCM). The numerical model uses the Finite Volume Method to solve the conservation equations of mass, momentum, and energy. A 3D transient thermal model incorporating the PCM enthalpy formulation was developed to analyze the PV panel temperature. The thermal model considers the energy transfer by conduction, convection, and radiation throughout the day. A mean absolute deviation of 3% was obtained for the PV panel temperature by comparing it with experimental data available in the literature. After the numerical model validation, the PCM was changed to a bio-based PCM (bioPCM) consisting of la uric acid, whose melting point is relatively high (from 4446 °C), allowing its use in regions of high solar incidence. Furthermore, it has a high latent heat of fusion, being chemically stable and non-toxic. Using the proposed bioPCM, a temperature reduction of 9 °C was obtained, increasing the energy production, on average, by 9% compared to a conventional PV without PCM. Overall, using the proposed bioPCM can avoid excessive losses of energy-conversion efficiency under high irradiance conditions and extend the lifespan of photovoltaic panels.