Sandia National Laboratories researchers have analyzed AeroShield Materials Inc.’s flat plate collector system, which integrates a novel aerogel insulating material within non-concentrating, flat plate collectors, enabling them to achieve high efficiencies with peak temperatures exceeding 150°C, potentially making the system cost-competitive for facilities using fuel oil or diesel. Sandia engineers working in concentrating solar power (CSP), along with engineering firm EtaJoule, recently had an up-close look at the material, and a chance to share their capabilities and expertise with the Round 4 American-Made Solar Prize winning company.
“Working on the AeroShield project through the American-Made Solar Prize competition has expanded my understanding of the scope of solar thermal technology that can provide process heat at a wide range of temperatures necessary to decarbonize the industrial sector,” said Nathan Schroeder, the lead researcher on the project.
Flat plate collectors absorb thermal energy from sunlight similar to the way your dashboard is heated on a warm summer day, said Schroeder. The solar energy transmits through the glass (the windshield) where it is absorbed by the collector (the dashboard). The glass prevents the absorbed heat from escaping the system. AeroShield Material Inc.’s novel aerogel layer provides a highly transparent, yet insulative layer, which better contains the heat within the system, he said.
Typical flat plate solar collectors are only able to achieve maximum temperatures up to ~80°C due to significant thermal losses through the collectors’ glass aperture, Schroeder said. A lower maximum temperature corresponds to a lower thermal efficiency for the whole system. To combat these losses, some common collector designs feature multiple layers of glazing (i.e. glass) to decrease thermal losses but these designs have a tradeoff, in that they also decrease the total transmitted solar irradiance into the receiver. AeroShield’s aerogel insulating layer provides substantial thermal resistance to the collectors’ aperture, while maintaining high solar transmissivity, which increases the net thermal energy delivered to the system and maximum system temperature. AeroShield’s flat plate collector system was able to operate at temperatures above 120°C at 48% efficiency.
Sandia used its capabilities and expertise to provide AeroShield Materials Inc. with a number of tools to determine the system levelized cost of energy (LCOE) based on deployment location and operating temperature. AeroShield can leverage this capability to provide a detailed analysis of the system’s cost to the end user, potentially increasing market adoption and accelerating industrial decarbonization.
“Sandia was the perfect partner to help AeroShield validate the performance of our proposed system,” said AeroShield Co-Founder, Aaron Baskerville-Bridges. “We leaned on the teams’ expertise in solar thermal, optical modeling, and EES models, and the final deliverable helped us understand the impact our design choices had on performance. Even more importantly, we can use these models again and again to test new designs and ideas as we scale up and develop new prototypes.”
“AeroShield’s technology could open up many process heat use cases as ~30% of process heat applications involve temperatures below 150°C including pasteurization, drying, and sterilizing,” Schroeder said. “Analysis showed the system could provide distributed rooftop thermal energy with storage at 120°C for a LCOE of 9 to10 cents per kilowatt, which would be cost-competitive for facilities using fuel oil or diesel, and efficiency and LCOE would only improve at lower temperatures.”
Brantley Mills, a thermal analyst at Sandia who also worked on the project, agreed. “Working with cutting-edge companies like AeroShield Materials Inc. through the American-Made Solar Prize has been a rewarding experience for me. It was exciting to participate in this technology’s development and see the broad range of different solar technologies that will contribute to a decarbonized future.”
To learn more, visit the National Solar Thermal Test Facility and AeroShield.
The American-Made Solar Prize is directed and administered by the National Renewable Energy Laboratory and is funded by the U.S. Department of Energy’s Solar Energy Technologies Office.