SEMINAR: Techno-Economic Development for Supercritical CO2 Advanced Energy Conversion
Supercritical carbon dioxide (sCO2) recompression Brayton cycle offers higher plant efficiency than the traditional Rankine superheated steam cycle as the turbine inlet temperature is increased beyond 500oC. The compact turbo-machinery, simple configurations, and dry cooling are characteristics driving interest in sCO2 cycle across a range of power generation areas. These characteristics are due to the attributes of supercritical CO2, primarily high fluid density, low viscosity, and high heat capacity when CO2 is compressed to pressures above 7.4 MPa at temperatures above 31°C, allowing the closed Brayton cycle to be optimized for particular performance characteristics. Because sCO2 power cycles offer advantages across a range of operating temperatures, sCO2 power cycles are being considered for next generation utility scale fossil fuel power generation, modular nuclear power generation, solar-thermal power generation, shipboard propulsion and house power, geo-thermal power, and industrial scale waste heat recovery.
In this talk, the fundamental technical challenges and developments needed to commercialize the cycle will be discussed. Thermal-hydraulic aspects, issues associated with the proposed compact diffusion bonded heat exchangers will be addressed in detail. Turbomachinery issues experienced during tests at Sandia National Laboratories will be summarized along with the scaling aspects to commercialize the turbomachinery components. Because of the close approach to the critical point, nucleation can be potential issue in the turbomachinery components and efforts to simulate this behavior in a laboratory scale testing will be discussed. Also there is a constant push to increase the source temperature for concentrated solar power (CSP) to 800oC and sCO2 Brayton cycle efficiency can reach the value as high as ~60% for such heat sources. The material challenges for such high pressures and temperatures applications will be discussed along with on-going efforts to develop ceramic based heat exchangers for CSP applications. Use of ceramic components along with the implementation of dry air cooling for the CSP cycles is considered as the future for cheap and reliable electricity. Work was performed in collaboration with Argonne National Laboratory to reduce the capital cost of dry air cooled sCO2 cycles.
Associate Professor and J. Erskine Love Jr. Faculty Fellow, George W Woodruff School of Mechanical Engineering, Daniel Guggenheim School of Aerospace Engineering (Courtesy Appointment) , Georgia Institute of Technology
Dr. Devesh Ranjan is an Associate Professor and J. Erskine Love Jr. Faculty Fellow in the GWW School of Mechanical Engineering at Georgia Tech. He was previously a director's research fellow at Los Alamos National Laboratory (2008) and Morris E Foster Assistant Professor in the Mechanical Engineering department at Texas A&M University (2009-2014). He earned a bachelor's degree from the NIT-Trichy (India) in 2003, and master's and Ph.D. degrees from the UW-Madison in 2005 and 2007 respectively, all in mechanical engineering. His research program focuses on the shock-driven mixing and combustion, the physics of hydrodynamic instabilities, and advanced power conversion cycles. He is a recipient of National Science Foundation CAREER Award, US AFOSR Young Investigator Award and the DOE-Early Career Award. He is currently an Associate Editor of ASME Journal of Fluids Engineering and serves on the Editorial board of Shock Waves (Publisher-Springer & Verlag).