Advanced science.  Applied technology.


SwRI receives $3.2 million contract from Energy Department for solar power research

San Antonio — Sept. 17, 2015 — Southwest Research Institute (SwRI) has been awarded a $3.2 million contract by the U.S. Department of Energy SunShot Initiative. The contract is part of an $8.8 million effort to design, manufacture, and test an ultra-high efficiency supercritical carbon dioxide (sCO2) compressor-expander for power generation at concentrating solar power (CSP) plants. CSP plants use mirrors to concentrate the energy from the sun to drive traditional steam turbines or engines that create electricity.

SwRI turbomachinery engineers will collaborate with Samsung Techwin America (STA) to develop an integrally geared compressor-expander, or “compander,” for use in an sCO2 plant. The compander is a turbine through which a high pressure gas is expanded to drive a multi-stage gear compressor. This integrally geared compander (IGC) has the potential to improve efficiency, modularity, and process control. The technology provides a critical step toward making sCO2 CSP power plants commercially viable.

“This project is one of 11 sCO2 power cycle projects SwRI is conducting for the Energy Department. The goal of these projects is to develop the critical technology building blocks needed to make sCO2 power cycles technically feasible and commercially viable,” said Dr. Klaus Brun, a program director in SwRI’s Mechanical Engineering Division.

IGCs increase overall machinery efficiency, and are widely used in both air separation and process gas industries. Because all of the turbomachinery elements are integrated into a single machine, the design optimally lends itself to a modular power block, making it suitable for waste heat recovery, fossil fuel power plants, and especially CSP applications.

“STA is pleased to collaborate with SwRI on the design of an IG compressor-expander and believes that this technology will provide viable solutions to many of the practical challenges associated with sCO2 power cycles,” said Dr. Karl Wygant, vice president for the STA Turbomachinery Design and Development Center in Houston.

The compander design project also includes development of an sCO2 compressor impeller that incorporates novel flow path designs for maximizing compressor efficiency and mechanical reliability under a wide range of inlet conditions. These novel flow path designs are enabled through direct metal laser sintering, an additive manufacturing process that increases design flexibility and produces high-strength parts.

The project, which will be conducted in three phases, begins in October 2015 and will continue through September 2018 pending awards for subsequent phases. SwRI project managers for the newly funded contract are Group Leader Dr. Tim Allison and Research Engineer Dr. Jason Wilkes, both of SwRI’s Mechanical Engineering Division.

For more information about SwRI’s Machinery Program, visit

About the SunShot Initiative: 
The U.S. Department of Energy SunShot Initiative is a collaborative national effort that aggressively drives innovation to make solar energy fully cost-competitive with traditional energy sources before the end of the decade. Through SunShot, the Energy Department supports efforts by private companies, universities, and national laboratories to drive down the cost of solar electricity to $0.06 per kilowatt-hour. Learn more at

For more information, contact SwRI Solutions.