Analisis Termo-Ekonomi pengaruh Metode Penyemprotan Air untuk Inlet Udara pada Air Cooled Condenser terhadap Performa Pltp Sarulla menggunakan Aspen Plus

Abstract

One of the geothermal energy conversion systems is the binary generation cycle, which is mostly air-cooled. Air-cooled geothermal plants are highly dependent on the dry bulb temperature of the air. An increase in ambient air temperature results in an increase in condenser pressure and turbine back pressure, thus causing a significant decrease in the efficiency as well as the net power of the power plant. In this study, power plant optimization is carried out with an evaporative cooling method in the form of spraying water into the air which is numerically simulated in Aspen Plus software. This water spraying method is also analyzed from a thermodynamic and economic perspective. The plant studied is the Sarulla Geothermal Power Plant, Silangkitang Unit in North Tapanuli, North Sumatra, Indonesia. The findings of this study are a power increase of 1.401% in the binary cycle that utilizes the residual steam of the steam turbine output as the pentane heater (Bottoming cycle) and 3.59% in the binary cycle that uses the separator output brine as the heating fluid (Brine cycle). Optimization with the water spraying method is also able to increase annual electricity production by 673 MWh/year with a water consumption of 2097 tons. The thermal efficiency of the plant also increased, by 1.1% in the Bottoming cycle and 2.8% in the Brine cycle. In particular, the economic analysis of the water spraying system was evaluated to determine its feasibility factor as a project. The results show that the water spray cooling system project is feasible by generating a Net Present Value (NPV) value of $183,803.66, an Internal Rate of Return (IRR) value of 148.47%, and a Payback Period of 0.29 years or 4 months.