Sandia’s Supercritical Carbon-Dioxide/Brayton-Cycle Laboratory Signs Important MOU with Industry Partners

Sandia and eight other companies and research organizations^* will collaborate to advance a distributed power system that can produce cleaner, more efficient electricity. The memorandum of understanding (MOU) focuses on developing an energy-conversion system based on supercritical carbon dioxide (sCO₂)/Brayton-cycle technology. Gary Rochau, manager of Sandia’s Advanced Nuclear Concepts Dept. said sCO₂/Brayton cycle technology could bring about large-scale improvements in production across most energy sectors, especially solar, nuclear, and gas turbine. Potential economic and environmental benefits include reduced fuel consumption and emissions and the ability to generate power from a variety of heat sources, he said.

Jim Pasch, principal investigator of the sCO2/Brayton-cycle R&D program, and Darryn Fleming, principal investigator of the sCO2/Brayton-cycle heat-exchanger program, investigate a turbine and compressor inside a test facility at Sandia. (Photo by Randy Montoya)

The term “supercritical” refers to the semi-liquid CO₂ state when it is above its normal critical temperature and pressure, where the working fluid basically has the momentum of a liquid and the friction properties of a gas—allowing sCO₂-based systems to operate with very high thermal and kinetic efficiency—to much more efficiently convert any kind of thermal energy (whether it be from concentrated solar, nuclear, or fossil-fuels) into electricity.

Sandia’s Brayton Lab in Albuquerque is the only sCO₂ research facility of its kind. The partners plan pilot testing there, using a gas-turbine engine based on a 6 MW energy-generating system developed by Peregrine Turbine Technologies that uses sCO₂ as a working fluid. CEO David Stapp said it could be 30%–60% more efficient than current technology. These turbines are also significantly smaller than those now used in current power plants. For example, their 20 MW generator takes up only 4 m³, where a typical 20 MW Rankine-cycle steam turbine generator takes up 240 m³ (12 × 4 × 5 m), 60 times as much space (and that larger mass also means much higher materials/manufacturing costs). A second prototype engine would likely be tested at the US Space & Rocket Center.

“This is the first large collaboration to identify partnerships that will take the DOE’s lab-scale technology and accelerate its development to commercial industry deployment of a highly efficient, low-carbon emission, electrical power generator,” said Rochau.

The MOU allows our organizations to work easily together to accomplish similar goals

• advancing the commercialization readiness of the sCO₂/Brayton-cycle technology;
• providing world-class testing and analysis; and
• encouraging the establishment of US-based, high-value technology and manufacturing jobs.

The Sandia sCO₂/Brayton-cycle team, working under a cooperative research and development agreement (CRADA) with Vacuum Processing Engineering, Inc., has also recently

• developed a design code (rules for the design of a new technology);
• obtained ASME Process Code stamps (third party certification of process quality); and
• built the first US-manufactured diffusion bonded, printed-circuit heat exchanger.

Based on preliminary testing, this heat-exchanger technology will reduce the cost of heat exchangers by a factor of 10 and improve efficiency up to 10% over conventional shell-and-tube heat exchangers, which are currently in use world-wide.

Read the Sandia news release.temp

^*Organizations signing the memorandum of understanding with Sandia are

• Peregrine Turbine Technologies and its subsidiary PTT Distributed Energy Systems (Wiscasset, Maine);
• Vacuum Process Engineering (Sacramento, California);
• Mid-South Engineering (Hot Springs, Arkansas);
• CFD Research Corp. (Huntsville, Alabama);
• US Space & Rocket Center at NASA’s Marshall Space Flight Center (Huntsville, Alabama);
• Government Energy Solutions Inc. (Huntsville, Alabama); and the
• Energy Huntsville Initiative (Huntsville, Alabama).