Novel turboexpander operates in gas, gas-liquid states

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Recent testing of the RadMax prototype gas expander with compressed air produced predicted torque and power generation at all tested speeds, the company Regi U.S. has said. In the tests, torque produced by the RadMax expander was used to generate measured electric power through the use of a belt driven alternator connected to an adjustable electrical load.

Sufficient startup torque was produced by the expander to easily self-start the unit and the alternator. Collected inlet and outlet pressures and temperatures confirmed that the torque created was due to the desired gas expansion process.

Produced torque was also verified using a Prony brake dynamometer. Measurements were taken at start up and at various speeds. Test findings prove that the RadMax sliding axial-vane technology can be used to create an effective and efficient gas expander.

Design enhancements and testing are expected to continue through the first quarter of 2018 to optimize efficiency, materials and collect wear and durability data. Development for integrating electricity producing components directly into the expander will also continue during this time.


The RadMax expander has the capability to effectively operate in both gas and gas-liquid states. Proving the RadMax expander concept is the first major milestone in developing the RadMax Two-Phase Expander (TPX) and the Two-Phase Expander Generator (TPXG) which are predicted to extract 10 – 20 percent of the available pressure-volume energy normally lost in throttling operations.

Initial targeted applications for the RadMax TPX and TPXG are the large commercial markets for air conditioning, refrigeration, natural gas distribution and other applications where throttling valves are commonly used, such as the Petrochemical Industrial sector. We are currently actively pursuing industry leading development partners in these markets.