United States Patent #9,920,749 - Awarded March 20, 2018 to Ormat Technologies, Inc.
A method for producing power from two geothermal heat sources includes:
- separating a first geothermal fluid from a first geothermal heat source into geothermal vapor comprising steam and non-condensable gases, and geothermal brine;
- supplying the geothermal vapor to a vaporizer;
- vaporizing a preheated motive fluid using heat from the geothermal vapor, wherein the heat content in the geothermal vapor exiting the flash tank is only enough to vaporize the preheated motive fluid in the vaporizer;
- expanding the vaporized motive fluid in a vapor turbine producing power and expanded vaporized motive fluid;
- condensing the expanded vaporized motive fluid to produce condensed motive fluid; and
- preheating the condensed motive fluid in a preheater using heat from a second geothermal fluid from a second geothermal heat source having a lower temperature and salinity content that the first geothermal fluid, thereby producing the preheated motive fluid, make-up water and heat-depleted geothermal brine.
