For many decades, aluminum extrusions have been proven a cost-effective solution in applications 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 makes extrusions a good choice for solar frames and mounting systems.
The most successful designs using extrusions do not simply replace steel with aluminum to take advantage of the material’s corrosion resistance, low maintenance costs or light weight and strength, but incorporate the ability of the extrusion process to place metal where functionally required for structural, fastening and other purposes. The infinite number of extruded profiles available is dependent only on the creativity of the designer to best match the needs of the product to the process and material capabilities.
Extrusions are widely used in both photovoltaic (PV) and concentrated solar power (CSP) mounting systems and frames, providing enhanced performance and reduced costs over earlier designs and other materials, such as steel.
The utility-scale power parabolic trough CSP facilities at Nevada Solar One, in installations in Spain and in the Martin Florida, “hurricane-strength” design prove that when properly designed, extruded aluminum solutions provide a long-term cost-effective solution providing high performance in the most demanding environments.
IBIS Associates, a strategic material consulting firm, is internationally known for highlighting the 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, extrusion’s design flexibility enabled optimized structural solutions: low cost, light weight, superior performance and other design advantages.
The study proved that extruded systems yielded highperformance, 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 20 years were evaluated, concluding that there would have been no time during the past 20 years when a steel solution would have been a better choice than aluminum.
Experts emphasize that to save up to 20% of the material cost, designers should only specify anodized or painted extrusion surfaces where required for aesthetic reasons or in extremely hostile environments (protective surface finishes are not needed for extrusions in typical solar installations). Designers should also take liberal advantage of extrusion’s low tooling costs and quick tooling delivery to allow for sequential prototyping of ideal solutions – costs were reduced by 40% in one recent project by doing this.
Engineers receive adequate education regarding steel as a structural material but receive little exposure to using extruded aluminum solutions. Ironically, the inherent design flexibility of extrusions becomes one of its largest challenges for designers. Design software analyzes the limited few steel profiles in a tabular fashion, but can’t yet adequately and efficiently analyze the almost infinite number of profiles possible from aluminum extrusions. Hence it is most worthwhile to contact an extruder early in the design process, to capitalize on their in-depth design experience.
The Aluminum Extruders Council team is working to provide design software with the key formulae necessary to properly support the use of aluminum extrusions in a truly parametric design fashion, bridging the “gap” in design support. This in turn will help drive the creativity of aluminum solar structural designs, further enhancing the performance and reducing the total cost of ownership—both critical to ensuring the future of solar power systems.
By: Craig Werner, owner of Werner Extrusion Solutions and past chair of the Aluminum Extruders Council
Learn more about the advantages of using aluminum in your next solar project in:
Installation Practices: The Case For Aluminum Solar Racking Systems
Webinar: Creating Cost Effective Solar Installations With Aluminum Extrusions
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