Session: 30-11 System Testing

Paper Number: 152150

Extended Duration Operation of a Pilot-Scale Supercritical CO2 Test Loop 

Supercritical carbon dioxide (sCO₂) power cycles offer significant advantages over steam and organic Rankine cycles particularly for high temperature thermal input, but remain a relatively new technology with limited extended duration operations and testing experience. As part of a test of a solid-fueled heater system, a simple recuperated sCO₂ test system was designed, built and installed at the San Rafael Energy Research Center for extended test operations. The system design parameters included a maximum pressure of 20 MPa, and a maximum primary heater discharge temperature of 600°C, and a design CO₂ flow rate of 5 kg/s. The design point thermal input from the fired heater to the CO₂ working fluid was 1.2 MW. Residual heat rejection to the environment was via evaporative water cooling using a conventional cooling tower, and the CO2 to water heat exchanger was of the diffusion-bonded heat exchanger type. The recuperator was of similar design, while the primary heat exchanger was similar to a tangent-tube fired boiler design, while the heat source was alternately coal and natural gas.

The primary purpose of the test campaign was the demonstration of the fired heater - thus a work-extraction turbine was not included in the system for simplicity. A variable area throttle valve was used to control the system flow and pressure, allowing for more flexible operation than possible with a fixed geometry turbine.

A robust closed-loop control system was designed for the test system permitting unattended fully automated operations. During the test campaign, extended duration fired testing in excess of 200 hours of continuous operation were successfully achieved including several switches between gas and solid fuels, and variation in firing rate. 

Presenting Author: Timothy Held Echogen Power Systems

Presenting Author Biography: Dr. Timothy Held is the Chief Technology Officer at Echogen Power Systems in Akron, Ohio, where he is responsible for development, maturation, and transition to product of supercritical CO2 power cycles and energy storage systems. Prior to joining Echogen in 2008, Dr. Held was with GE Aviation for 13 years, where he held leadership positions in several combustor design and fuels technology teams. He received a BSAAE from Purdue University in 1987, and a Ph.D. in Mechanical and Aerospace Engineering from Princeton University in 1993. He has published several technical journal articles and book chapters, and holds 49 U.S. patents.

Authors:

Timothy Held Echogen Power Systems
Kyle Sedlacko Echogen Power Systems
Brett Bowan Echogen Power Systems
Jason Miller Echogen Power Systems
Vamshi Avadhanula Echogen Power Systems
Andrew Fry Brigham Young University
Brian Schooff Brigham Young University