This project is designing, developing, and testing a supercritical carbon dioxide (sCO2) heat exchanger that operates at temperatures higher than 720°C and record-high sCO2 pressures. In sCO2 heat exchangers, heat is transferred from hot particles to carbon dioxide, which expands in a turbine to generate electricity. Industry experience with similar heat exchangers is limited to lower pressures, lower temperatures, or alternative fluids like steam or water. Sandia is partnering with three experienced heat exchanger manufacturers to develop several designs that achieve both high performance and low cost. A prototype unit will be manufactured and tested to confirm key metrics for performance and cost. This project builds off of the High-Temperature Falling Particle Receiver project in the 2012 Concentrating Solar Power (CSP) SunShot R&D funding program.
The research team is designing fluidized-bed and moving packed-bed sCO2 heat exchangers which will be tested with a flow system to determine required temperatures and pressures for superior operating conditions. Both heated and unheated tests will determine if the flow system has high flow rates and excellent thermal-hydraulic performance.
Researchers will use the newly designed sCO2 heat exchanger and flow system to scale-up the design to a multi-megawatt plant to gauge cost estimates and design uncertainties. By identifying these relative costs, uncertainties, and potential for cost reductions, researchers can determine the target cost of the sCO2 heat exchanger necessary to meet SunShot goals. The scaled-up heat exchanger design with performance and cost estimates will reduce risk of industry adoption and will enable the Department of Energy to make informed decisions regarding future research.