Outdoor Recreation Store
Alterra Solar
Racking System: rmdt
Structure Type: Small Commercial
Location: Monterey, CAlifornia
Completed: December 2020
Challenge
The owner of this retail shop and warehouse just outside Watsonville, California, had recently reroofed the building and wanted to avoid attachments despite being in one of the most seismically active regions of the United States.
Energy density was also a central goal despite the small footprint. As the design became more complex due to code changes, Unirac’s design team helped the installer navigate a number of questions and issues to produce a system that met the requirements.
Solution
Emil Carson, Engineering Manager at Allterra Solar, started with U-Builder (https://design.unirac.com) and chose Unirac’s Roofmount Dual Tilt (RMDT) because it’s known for frequently providing the greatest yield for a given square footage. He knew ballast weight wasn’t likely to be an issue because of the unique background of the building, which was initially built to robust government standards. “It’s a super-beefy building,” Carson says. “There was no worry about handling the weight.”
The project had originally been permitted in 2019. In 2020, as project installation neared, ACSE 7-16 had been adopted. “We had to totally repermit the job,” Carson said. When Allterra reached out to Unirac to verify the ballast-only solution and the impact of the code changes, they found that setback requirements in particular required a redesign.
Parapets also became a greater factor with the new code, helping with seismic values but adding to wind loads. Anima Bista, a Civil Engineer at Unirac who has crafted many of its software design tools, did the majority of the calculation herself, using values from the Sustainable Energy Action Committee (SEAC) and other sources, but also coordinated with Unirac’s team in India to minimize turnaround times.
Implementation
As Allterra began work, it encountered many obstructions on the roof, some significant enough that the roofer eventually returned to remove a number of them. “Every time I had to change it, I sent it to Anima and she would get the ballast report back to me,” Carson said. The RMDT system itself went together quickly and easily. “The installers loved it.
IT WAS REALLY NICE TO HAVE UNIRAC THERE TO SUPPORT US. ANIMA, MARK AND PATRICK WERE SUPER HELPFUL. YOU FEEL LIKE YOU’RE IN THE DARK SOMETIMES, AND WHEN YOU GET THAT SUPPORT, IT FEELS REALLY NICE.
Emily Carson, Engineering Manager, Allterra Solar
Benefit
The project was completed in December 2020. The end customer obtained a 114.21kW system made up of just over 280 Jinko JKM 405-watt modules in a dual-tilt configuration. The system, as requested, had no penetrations.
