Session: 07-01 Air-Based Energy Storage Systems

Paper Number: 82263

82263 - Organic Rankine Cycle Turbine and Heat Exchanger Sizing for Liquid Air Combined Cycle 

Cryogenic energy storage offers several opportunities to design turbomachinery and other equipment for novel cycles. This paper presents the design and analysis of turbomachinery and heat exchangers for an Organic Rankine Cycle (ORC) subsystem for a hybrid energy storage concept. The Liquid Air Combined Cycle is a cycle that stores air at cryogenic conditions at times with high variable renewable energy that can be dispatched along with a gas turbine to recover the exhaust heat. In order to re-vaporize the air, the liquid air is coupled with an ORC as an additional bottoming cycle. The ORC turbine is expected to expand the fluid with a pressure ratio of nearly 30 and a flow rate of approximately 45 kg/s. Sizing calculations for both a radial and axial turbine solution were performed over a range of speeds and stages to determine the optimal design point. The final design for the ORC turbine was that it would be an axial turbine with 7 stages split into two shafts and housings to meet the requirements of the system. The ORC system also incorporates five heat exchangers to distribute heat, vaporize the liquid air, or recover exhaust heat from the gas turbine. The heat exchangers were analyzed to understand the size of heat exchangers and pressure drop for the overall system. Different types of heat exchangers were explored for the different purposes, including plate-fin heat exchangers, counter-flow heat exchangers and shell-in-tube heat exchangers. It was determined that the ORC recuperator, liquid-air vaporizer, and vaporized air heater would be counter-flow heat exchangers, while the remaining two heater exchangers were better suited as shell-in-tube heat exchangers.

Presenting Author: Owen Pryor Southwest Research Institute

Presenting Author Biography: Dr. Owen Pryor is a research engineer at Southwest Research Institute. Dr. Pryor’s research interests include thermodynamic cycle design, analysis and optimization, energy storage, turbomachinery design and supercritical CO2 cycles. At SwRI, he has designed and commissioned trans-critical CO2 systems and developed a transient operational model for an energy storage system. Dr. Pryor received his Ph.D. in Mechanical Engineering form the University of Central Florida in 2018 where he studied combustion characteristics of different fuels and worked developing laser diagnostics for the DOE Co-Optima Fuels program.

Authors:

Owen Pryor Southwest Research Institute
Aaron Rimpel Southwest Research Institute
William Conlon Pintail Power LLC