Evaluasi dan Optimasi Pembangkit Listrik Tenaga Panas Bumi Unit 1-2-3 Kamojang Berdasarkan Analisis Exergi
The development of Kamojang Unit 1-2-3 since the 1980s marked the first utilization of Indonesias geothermal field. Kamojang Unit 1-2-3 constantly produces 140 MWe with high quality Equivalent Availability Factor (EAF) of 93% in average which comes from 1,000 T/h steam supply.
Within production period, Kamojang reservoir pressure and temperature decreases around 9.3 bara and 19°C from its initial condition which affects the production rate of 3% decrement per year.
In term of overall sustainability of Kamojang geothermal field, especially from the power plant perspective, concerns arise to improve power plant efficiency. Exergy analysis method is used to describe and determine the overall system losses.
Based on exergy analysis, Kamojang Unit 1-2-3 has system losses about 104,431 kW of exergy and exergy efficiency of 57.62%. Condenser corresponds the largest loss from the system of more than 30% of exergy.
The improvement were estimated on cooling tower system, that cooling water outlet temperature slightly change from its existing condition of 33°C into 29,44°C. This can be done by modify the water inlet flowrate to 90% (11.160 m3/h) and increase air inlet flowrate to 110% (11.107,49 m3/h). The result shows turbine steam flowrate increment of about 3.22 kg/s or 11.59 T/h for a single unit.