Description and Test Results from a Supercritical CO2 Brayton Cycle Development Program

The Supercritical CO2 Brayton cycle (S-CO2) can potentially offer more efficient and compact power conversion systems for advanced nuclear reactors, solar, or fossil fuel systems. The DOE Office of Nuclear Energy, Knolls Atomic Power Laboratory, and Sandia National Labs are investigating this cycle in a phased development program because it has the potential for high efficiency (in the temperature range from 400 °C to 750 °C), is very compact making it transportable, and may reduce capital costs due to the very compact turbomachinery. This paper describes resent test results from a supercritical CO2 closed Brayton cycle test loop. Sandia manufactured the loop through its contractor Barber Nichols Inc. The paper describes experimental test measurements of the main compressor performance map, the operational behavior of the supercritical loop at the critical point and below the critical point, and it illustrates the approach to break-even power production at very low turbine inlet temperatures (60 °C / 140 °F) using 78 kW of heater power.