PRACTICAL ASPECTS OF SUPERCRITICAL CARBON DIOXIDE BRAYTON SYSTEM TESTING

The supercritical carbon dioxide (S-CO2) Brayton cycle has been gaining interest in recent years due to its high efficiency and compact components. Bechtel Marine Propulsion Corporation (BMPC) is testing an S-CO2 Brayton system at the Bettis Atomic Power Laboratory. The Integrated System Test (IST) is a two shaft recuperated closed Brayton cycle with a variable speed turbine driven compressor and a constant speed turbine driven generator using S-CO2 as the working fluid designed to output 100 kWe. This paper presents practical aspects of S-CO2 Brayton cycle operation including loop purge and fill operations and system leakage as well as design considerations including thermal stresses, material quality and loop cleanliness, and instrumentation. Additionally, operational test data for CO2 temperature, pressure, and density are presented and comparisons made on the ability to accurately calculate CO2 density using REFPROP for an operating Brayton loop.