Learn more about NREL's capabilities in collector/receiver characterization.
Receiver research at NREL focuses on developing and validating advanced thermal receiver technologies and absorber materials for use in concentrating solar power (CSP) systems. NREL's high-temperature power tower receiver concepts currently under development include the fluidized-bed particle receiver and the direct supercritical carbon-dioxide (s-CO2) receiver, which are both capable of generating thermal power at temperatures greater than 650°C (1200°F) at targeted thermal efficiency of more than 90%. NREL also works to characterize and improve selective coatings for both line-focus and power tower receivers and to advance cleaning methods that ensure high performance and durability of CSP systems.
In a CSP system, the sun's rays are reflected onto a receiver, which converts the sunlight into heat that is used to generate electricity.
Opportunities and Potential Impact
Advancing CSP systems to the target cost of $0.06 per kilowatt-hour, set by the U.S. Department of Energy (DOE) SunShot Initiative, will require advanced CSP system components that operate at the high temperatures needed to significantly increase conversion efficiency. It will also require significant improvements to the lifetime reliability of system components to drive down costs of system installation and maintenance.
Revolutionary power conversion systems must operate at high temperatures without depending on water and fluids. And advanced receivers will need to be developed to integrate with these next-generation power systems.
Current Research Projects and Our Innovation
NREL's research on receivers focuses on several key areas:
- Direct supercritical CO2 receiver—Developing efficient thermal receivers that work at high temperatures and are compatible with the s-CO2 power cycle to increase the thermodynamic conversion efficiency of CSP systems.
- Fluidized-bed particle receiver—Developing a high-temperature thermal receiver for power tower applications using an innovative solar-only version of existing fossil boiler technology.
- Advanced solar receiver coatings for heliostats—Developing, characterizing, and refining advanced coatings to increase solar absorption and decrease emissivity to increase receiver efficiency. High-temperature solar-selective coatings for power tower receivers—Developing advanced coatings with Sandia National Laboratories that meet the high-performance requirements of large central receivers.
- Solar Power tower Integrated Layout and Optimization Tool (SolarPILOT)—Developing a code to address the performance and layout requirements for power tower systems. This tool integrates the rapid layout and optimization capability of the analytical DELSOL3 program with the accuracy and precision of SolTrace ray tracing.
Competitively Funded Project
NREL has won a competitive DOE award to fund the following project:
Facilities and Capabilities
- Large-Payload 2-Axis Tracker—Highly accurate and automated open- and closed-loop tracking.
- Optical Efficiency Test Loop—Fully automated test loop to complement laboratory measurements of receiver heat loss.
- Thin-Film Deposition Research Facilities—Equipment allowing NREL to develop advanced solar-selective and reflective coatings and to partner with industry to prototype and commercialize advanced selective coatings.
- Ultra-Accelerated Outdoor Testing—A system that simulates the harmful effects of long-term sun damage on outdoor products (such as coatings and paints) in just months, rather than decades.
- High-Flux Solar Furnace—A furnace in which NREL exposes, tests, and evaluates many components, including receivers, collectors, and high-temperature materials and coatings in an extreme solar environment.
- Receiver Optical Test Stand—A tool used to analyze the steady-state, off-sun thermal losses of receivers used in solar parabolic trough power plants; helps to reduce collector optical losses and reduce receiver heat loss at elevated temperatures.
- Infrared Camera Solar Field Survey (Thermal Scout)—A device to identify and analyze bad receiver tubes using a global positioning system, infrared camera, and sophisticated software that tracks and analyzes data in real time.
- Receiver Characterization Laboratory—Equipment to characterize line-focus receivers, to help reduce collector optical losses and further reduce receiver heat loss at elevated temperatures.
Through its innovative research and unique experience, facilities, and capabilities, NREL is working to accomplish the goal of the U.S. Department of Energy's SunShot Initiative to make installed large-scale solar energy systems cost-competitive with other energy sources by 2020.