Development of waste brine to energy system with Concentric Cylindrical Thermoelectric Generator (CCTEG) at Ulubelu Geothermal Power Plant

Abstract

The Ulubelu geothermal field plan to utilize geothermal energy through the direct use energy of brine. Develop waste to energy a Thermoelectric Generator (TEG) into the system represents an innovative approach to harness additional energy from the high-temperature brine before it is reinjected into the well. The Circular Construction Thermoelectric Generator (CCTEG) is designed using a double-pipe heat exchanger, with diameters of 1.02 m for the brine and 0.91 m for the cold water. The brine enters at 174°C with a mass flow rate of 763 kg/s, while the condensate water from the cooling tower is at 28°C. Simulation results show that the CCTEG requires 2309370 TEG semiconductors along a 32-meter length, achieving a power output of 538.25 kW with a total voltage of 51.2 kV and a current of 10.5 A. The system experiences pressure drops of 189 kPa on the hot side and 1,869 kPa on the cold side, utilizing 0.6% of the total brine energy potential of 79760 kW. This design demonstrates an efficient method to optimize energy extraction from geothermal resources.