Increasing the operating lifetime of photovoltaic (PV) modules is a key factor in further reducing their levelized cost of electricity. Analytical degradation models typically use the external relative humidity (RH) as a stress factor, rather than the moisture concentration inside the module. This study presents a Finite Element Method (FEM) model, built in COMSOL Multiphysics, to simulate the moisture ingress inside a PV module. We explore the effects of different encapsulant and backsheet materials, as well as various climatic conditions, on moisture penetration. Overall, the impact of the climate has a larger impact on the moisture ingress than the choice of material, implying that the PV module design should be adjusted for different climates. As FEM simulations are computationally intensive, we also present an analytical model, based on empirically determined characteristics, to simulate the moisture ingress. This reconstruction can be done with a deviation lower than 0.05 for all conditions. Finally, our findings indicate that the relative moisture content (RMC) within the module serves as a more accurate stress factor than outdoor RH. Degradation rates over time found in literature are captured more accurately when deploying RMC.

This work presents a practical approach to designing an optical filter for thermal management for photovoltaic modules. The approach emphasizes the practicality of manufacturing over optical performance. Simulation work demonstrates that, for an interdigitated back contact solar cell architecture, complete rejection of infrared radiation offers limited thermal benefits requiring highly complex optical filter designs. An alternative approach consists of reducing thermalization losses by providing reflectance at lower wavelength values. An optical filter design that fulfills this requirement is possible using simple structures based on two materials and taking advantage of the harmonics present in quarter wavelength optical thickness designs. The filter is later optimized for angular performance via second-order algorithms, resulting in a device consisting of only 15 thin-film layers. Performance simulations on two locations, Delft (the Netherlands) and Singapore, estimate a temperature reduction of 2.20°C and 2.45°C, respectively. In a single year, the optical loss produced by the filter is not compensated via temperature reduction. However, improvements in the annual degradation rate show that in Singapore, the overall effect of the filter on the lifetime DC energy yield is positive.