Hybrid cooling systems for low-temperature geothermal power production

The overall objective of this investigation is to identify and evaluate methods by which the net power output of an air-cooled geothermal power plant can be enhanced during hot ambient conditions using minimal amounts of water. This report addresses binary power plants that use a hydrocarbon as the working fluid and utilize an air-cooled condenser (ACC) for heat load rejection. We considered two configurations to mitigate losses in power production: 1) evaporative pre-cooling of the ACC inlet air (without the use of any added heat exchanger) and 2) the use of a water-cooled condenser/heat exchanger in parallel or series with the ACC (or an air-cooled heat exchanger (ACHX)) to split the total condenser load. Steam cycles, though not currently used in industry for low temperature geothermal resources, were also analyzed.