Design validation and calculation of a self-supporting and foldable solar panel system using FEA

Abstract

The potential for the production of green energy in the Netherlands is insufficiently utilized. The cause for this problem is the insufficient bearing capacity of industrial roofs for the installation of solar panels using ballast. This required ballast exceeds the bearing capacity of the roof structure, or exceeds the bearing capacity of the weak sections. To solve this problem, a new self-supporting and foldable solar panel system has been designed.
Research into roofs with insufficient bearing capacity, gained an insight in the different spans required for the system. Several existing foldable solar panel systems were found, together with lightweight solutions for roofs with low bearing capacity. Finally, a patent research revealed no patents causing infringements with the current support system design.
The solar panel support system has been designed with two functionalities. The first functionality of the system, is that it has been designed as a lattice structure. In this way, the system becomes a self-supporting structure, capable of spanning the weak sections of the roof. Another advantage of the lattice structure is, the required ballast is eliminated. The second functionality of the system is that it is foldable. In this way the installation time, and the required space for transportation, is reduced.
To determine the behaviour of the support system, a prototype test is executed. This prototype test will subsequently be used for the validation of the Finite Element Model. For the test, four A-frames have been assembled, after which several loads were applied. After applying each load, the deflection, reaction forces and tension forces in the steel cables were measured.
Validation of the simplified Finite Element Model is required, to determine if the model accurately shows the behaviour of the system. Validation is executed by comparing the measured quantities during the prototype test, with the model in the same conditions. After adjustments to the model, the model accurately represents the behaviour of the support system, and is therefore validated.
The validated model is used to analyse the support system according to snow and wind loads. For these analyses, a case study is executed based on an example from industry of a roof with insufficient bearing capacity. Several problem areas became apparent during the analysis of this case study. To solve these problems, design adjustments to the current design are proposed.
In this research, a method for the validation of a Finite Element Model using an experimental test for a self-supporting and foldable solar panel system is executed. It became also apparent that a test was required to adjust the model and accurately represent the behaviour of the system. This approach can also be used for different type of loadings, or can be beneficial or applicable to other systems.
With this model, future analyses for different cases can be executed and a contribution towards the production of renewable energy has been made. Re-analyses of the support system with the proposed design adjustments is required to determine if these adjustments are sufficient. Further optimization of the design can be executed using the suggested optimization techniques. For the application of the support system outside the Netherlands, recalculation of the system according to the applicable standards for snow and wind loads is required.