Effect of inhomogeneous loads on the mechanics of PV modules

Abstract

In contrast to homogeneous mechanical load according to IEC 61215, photovoltaic modules in the field are mainly exposed to inhomogeneous loads like snow or wind. This paper deals with such inhomogeneous loads using computational fluid dynamics and finite element method simulations. Temperatures different to room temperature and the choice of encapsulates have significant influences on the thermomechanics of a photovoltaic module in case of snow load. Polyolefin is the encapsulant with the lowest storage modulus and has the lowest overall stress in solar cells and glass down to −30°C. Furthermore, with colder temperatures, the first principal stress decreases in solar cells but increases in the glass. For wind loads, the impact of module orientation, wind direction, module inclination angle, and wind speed is analyzed. A crosswind scenario is found to be most critical. Additionally, as a rule of thumb, higher module inclination angles result in higher stresses. Finally, general thermomechanical rules are extracted allowing for a deeper understanding of the underlying effects and therefore help to build more robust modules in the future.

Mechanical Analysis of the Quasi-Static and Dynamic Composite Action in PV Modules with Viscoelastic Encapsulant

“…Among others, the pure mechanical performance and capacity assessment of PV modules as load-bearing components in buildings is of primary importance (see Section 2.1 ), not only because they are implicitly associated with the electrical functionality of the system, but also in terms of possible risk for people, in case of breakage. For this reason, for example, the PV module performance under inhomogeneous snow loads in cold temperatures (down to −30 °C) was investigated in [ 24 ], taking into account the encapsulant stiffening with extreme temperatures and the consequent stress modification in the glass cover.…”