An Illustration of Thermodynamic Modeling and Economic Analysis of Inlet Air Chilling System for Gas Turbine Power Augmentation

Inlet air chilling system has been widely used in recent years as a method of the gas turbine (GT) power augmentation in power plants. In this paper, thermodynamic modeling of inlet chilling system had been studied in order to improve the performance of the two units of gas turbines (GT1 & GT2) in Pesanggaran power plant, in Bali, Indonesia. The study was focused on power enhancement, specific fuel consumption (SFC), heat rate and thermal efficiency and conducted on three cooling conditions i.e. 17°C, 15°C and 13°C. Moreover, the economic analysis was conducted to determine the capacity cost, operating cost and payback period due to the investment cost of the system. Based on the simulation results, the lower the chilling temperature, the higher the power enhancement and the parasitic load on the system. The maximum power enhancements for GT1 and GT2 were at the lowest chilling temperature 13°C, i.e. 6.57% and 6.61%. Based on the evaluation of the economic aspects, capacity costs should be ideally balanced with a decrease in the production cost after the application of the chilling system, however, the power cost was not economical because it couldn’t compensate the investment cost and it had a very long payback period.