The objective of this project was to present a large photovoltaic array at 90 [+/-1] degrees to the sun at all times. This required two key features. Firstly the ability to mount all the individual cells flat [to within one degree] and secondly to move the array to follow the Sun’s position [within a similar tolerance]. For construction efficiency each array needed to be large [with a size of 5 x 6 metres].
Creating an excellent solution required simultaneous input from both the Finite Element team and our Manufacturing Feasibility team. Modelling the adhesive performance is important to achieving a realistic model for fatigue and wind loads, and this is an area where we have developed a good interaction with FE teams over several projects to achieve effective outcomes. As with an aircraft wing, the assembly needs to demonstrate elastic flexibility associated with the lightest possible mass.
The main supports for each of the sub assemblies are operating in shear and a folded sheet solution was the obvious approach for these components and at higher volumes a pressed solution is planned.
The photovoltaic cell support rails are based on extrusions which provide the predictable levels of sub assembly straightness required to meet the overall flatness tolerances required by the Customer.
Bonding the anodised sub components with a single part epoxy provides the structural performance and long term mechanical and thermal durability required for the space frames. All critical joints are backed up with mechanical fasteners for added peel resistance and robustness during the final assembly process on site and for maintenance loads.
Sub assembly fixturing appropriate to the initial volumes is based on simple aluminium plates.
We are pleased to have supported the team at Circadian Solar in this challenging and environmentally relevant project. www.circadiansolar.com