Technology & Research
Microsteam® Turbine
Euler Turbine
Variable Phase Turbine
Variable Phase Cycle

Variable Phase Cycle

The Variable Phase cycle is a patented power system that generates power from waste heat and geothermal resources. The Variable Phase Turbine enables an efficient system for waste heat recovery and geothermal power generation.

Heat is transferred to a pressurized liquid in a liquid-liquid heat exchanger eliminating a boiler, which has a pinch point limitation. The liquid is flashed in a near isentropic two-phase nozzle, driving a Variable Phase Turbine. The cycle is closed by condensing the vapor and subsequently pressurizing the liquid to return it to the heat exchanger.


The result is an increase in net power from a sensible waste heat source or geothermal resource by 20-40% relative to the traditional Organic Rankine cycle.


A variable phase turbine generating 1 MW is shown in the photo. The turbine operates at 3600 rpm directly driving a generator and the main pump for the power cycle. The entry to the turbine is at the top and is powered by flashing hot high pressure refrigerant that is produced by a heat exchanger with geothermal brine.The flashing refrigerant exits the turbine as shown directly into a condenser where it is condensed and recycled to the heat exchanger.

The second photo shows a complete power plant. The power plant was designed, manufactured and installed by Energent. Energent personnel commissioned the power plant and continue to operate it at the COSO Geothermal resource.

Please refer to our technical paper about the Variable Phase Turbine and its application to geothermal power production in a Variable Phase cycle for a more detailed description of the technology.