EFFECT OF ORGANIC RANKINE CYCLE MODIFICATION TO SYSTEM PERFORMANCE

Abstract

The Organic Rankine Cycle (ORC) is the most used power plant type in the world. The performance of this type of power plant is investigated as an alternative of means to produce electricity. Specifically, three subtype of ORC system are investigated: a simple ORC system, an ORC system with a recuperator, and a regenerative ORC system with open feedwater.
The brine data is based on the brine from Jailolo geothermal field located in West Halmahera, Indonesia. Previous exploration studies identified the field as two-phase water-dominated reservoir with a brine enthalpy of around 1100 kJ/kg and steam fraction of 20%. It is planned to inject the brine at a minimum temperature of 90°C.
Specifically, the effect of modification of usage on the performance of an ORC system, without changing the turbine inlet pressure is investigated in this study. It is found that modifying the system will improve the thermal efficiency and brine output temperature, especially in a regenerative ORC system. This improvement is offset by the increased demand for brine from the reservoir. It is also found that in this scenario the exergy efficiency increases if a recuperator is used but is reduced if a regenerative ORC system is used.