The unique capabilities of aluminum extrusions have been proven extensively for many decades in applications necessitating cost-effective solutions while requiring excellent strength-to-weight ratios, inherent resistance to corrosion and other critical capabilities. Aluminum’s proven performance in transportation, building and construction, and thousands of other applications have made extrusions an obvious choice for solar frames and mounting systems.
The most successful designs utilizing extrusions do not simply replace steel with aluminum to take advantage of the material’s corrosion resistance, low maintenance costs or light weight, they also incorporate the ability of the extrusion process to place metal where functionally required for strength, fastening and other purposes. There are an infinite number of extruded profiles available, dependent only on the creativity of the designer to best match the needs of the product to the capabilities of the extrusion process and material.
Extrusions are widely used in both photovoltaic (PV) and concentrated solar power (CSP) mounting systems and frames, with innovative designs continuing to provide enhanced performance and reduced costs over earlier designs and certainly versus other materials, such as steel.
The utility-scale power parabolic trough CSP facilities at Nevada Solar One, in multiple Spanish installations and in a “hurricane-strength” design for the Martin Florida NextEra Energy facility have shown that when properly designed, extruded aluminum solutions provide long-term exceptional performance in a cost-effective manner in the most demanding environments.
IBIS Associates, a strategic material consulting firm, is internationally known for its work in highlighting the incredible value of aluminum for light-weighting transportation applications. IBIS performed independent studies on the use of extruded aluminum in CSP and PV applications, conclusively proving that while aluminum may cost more on a dollar-per-pound basis, the design possibilities of the extrusion process enabled optimized structural solutions, with their light weight, superior performance and other design advantages leading to less expensive systems.
It was determined that the extruded systems yielded exceptional performance, the lowest “total installed cost” (material acquisition, extrusion, fabrication, transportation, subassembly and final field assembly) and an end-of-life value three times that of comparable steel systems. The fluctuations in acquisition costs of steel, zinc (for the galvanized steel) and aluminum over a 20-year period were evaluated. The study concluded that there would have been no time during the past 20 years when a steel solution would have been a better choice than aluminum.
A study by engineering firm MAADI Group concluded similar results when comparing the use of steel versus aluminum in structural applications, proving that despite a higher dollar-per-pound cost, the total cost of ownership of extruded aluminum pedestrian bridge systems was lower than steel alternatives.
Engineers typically receive a thorough education in the use of steel as a structural material. While extrusions have proven their worth over more than 60 years, engineers are simply not as familiar with utilizing extruded solutions, and engineering design software does not yet fully incorporate the analysis and optimization of extruded solutions versus steel systems.
Ironically, the inherent design flexibility of extrusions becomes one of its largest challenges. Design software can analyze the limited few profiles available in steel in a tabular fashion, while current software is challenged to adequately and efficiently analyze the almost infinite number of profiles possible from aluminum extrusions. Currently, the Aluminum Extruders Council, with the support of its members, is working to provide design software with the key formula necessary to properly support the use of aluminum extrusions in a truly parametric design fashion versus the limited tabular listing of steel shapes, thus bridging the “gap” in design support between extruded aluminum and steel components.
By: Craig Werner, Owner of Werner Extrusion Solutions and Past Chair of the Aluminum Extruders Council