3D printing enables new solar power receivers to better absorb sunlight

Engineers at Sandia National Laboratories have designed new fractal-like, concentrating solar power receivers that are up to 20 per cent more effective at absorbing sunlight than current technology.

Although most concentrating solar power facilities in the world are large, Sandia engineer Cliff Ho says the team designed the solar power receivers for small- to medium-scale use because India is interested in developing 1 megawatt or smaller facilities that could provide the appropriate amount of power for a small village or community.

Sandia National Laboratories intern Jesus Ortega inspects one of the new bladed receivers at Sandia’s National Solar Thermal Testing Facility. (Photo by Randy Montoya)

The team used powder-bed fusion to 3D print multiple fractal designs from Inconel 718, a high-temperature nickel alloy.

“Additive manufacturing enabled us to generate complex geometries for the receiver tubes in a small-scale prototype,” Ho said.

“When light is reflected off of a flat surface, it’s gone,” adds Ho. “On a flat receiver design, 5 percent or more of the concentrated sunlight reflects away. So we configured the panels of tubes in a radial or louvered pattern that traps the light at different scales. We wanted the light to reflect, and then reflect again toward the interior of the receiver and get absorbed, sort of like the walls of a sound-proof room.”

The new tubular designs work with conventional heat-transfer fluids for concentrating solar power, including molten salts and steam, but they can also use other media for heat transfer and storage.

Ho and the research team developed and tested multiple prototype fractal-like receiver designs scaled in size to work at small- and medium-scale concentrating solar facilities and found the designs that work best for each application.

Ho said both the U.S. and India are interested in pursuing supercritical carbon dioxide to develop the next generation of concentrating solar power technology because it can reach greater efficiencies with smaller footprints.

The smaller footprint and cost would help enable the possibility of small-scale (in the 1-10 megawatt range) supercritical carbon dioxide Brayton cycle-based concentrating solar power plants, making concentrating solar power more competitive with other types of renewable energy.

The receivers were designed and studied as part of a Laboratory Directed Research and Development project and are also being applied to Sandia’s work for the Solar Energy Research Institute for India and the United States, or SERIIUS.

www.sandia.gov