Numerical Modeling of a Novel Ejector Combined Flash-Binary Geothermal Power Cycle for Maibarara Geothermal Power Plant in Santo Tomas, Batangas, Philippines

The Philippines may experience an energy crisis because of the increasing energy demand, and the country’s resources are insufficient. Most existing geothermal power plants involve reducing the geothermal pressure below the saturation pressure for the fluid temperature and shifting from a pressurized liquid to a combination of liquid and vapor. The majority of the separated liquid, known as brine, will not be utilized in energy production. In this study, the numerical modeling of a Combined Flash-Binary Geothermal Power Cycle with Ejector that utilizes the waste brine from the Maibarara Geothermal Power Plant was proposed, and to analyze and select the optimal working fluid for the system, it was screened through the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). It is a multi-criteria decision-making numerical method (MADM). The model was simulated using MATLAB with CoolProp to determine the ejector profile and thermo-fluid dynamic parameters. The study shows that using a Novel Ejector Combined Flash-Binary Geothermal Power Cycle can efficiently utilize waste brine; the criteria for selecting the optimal working fluid have a significant impact; adding an ejector to the system that does not require other energy to operate can improve the system even further. The ejector combined flash-binary ideal cycle improves power output and thermal efficiency by 6.2681 MW and 5.3862%, respectively.