Comparative Study of Inlet Air Cooling Technologies for Gas Turbines Under Tropical Conditions

Abstract: In this paper, a comparative thermodynamic performance analysis is presented for Evaporative Cooling and Mechanical Chilling, two inlet air cooling techniques for simple cycle gas turbines in tropical environments. While numerous papers in the literature have examined different cooling methods, this study is particularly focused on the evaluation and comparison of the performance of these two widely employed techniques under Nigerian Climatic Conditions.

The research employs operating data from a Nigerian gas turbine power station combined with MATLAB-based modeling to simulate the effect of each cooling method. Performance was assessed under two Relative Humidities, 30% and 70%, typical of the country's two major climatic zones. The key parameters assessed are net work output, Thermal Efficiency, and heat rate.

The findings indicate that, against common belief, Evaporative Cooling performs more positively in both low- and high-humidity environments. Although Mechanical Chillers achieve ambient-independent cooling performance regardless of the ambient conditions, their advantage is limited to extremely high ambient temperature with high Relative Humidity conditions, where Evaporative Cooling becomes inefficient. In most other situations, Evaporative Cooling performs better in enhancing Gas Turbine performance.

These results necessitate the need for a climate-sensitive approach in the selection of Inlet Air Cooling technologies. Rather than adopting a single-fit-all approach, power plant operators are encouraged to align their choice of cooling systems with the prevailing environmental conditions in specific locations. Practical suggestions that can assist in improving overall efficiency and reliability of power generation in Nigeria's different climatic regions are provided by the study. By determining the conditions under which each cooling technology is optimally effective, the paper contributes to more informed decision-making in Gas Gurbine performance enhancement in tropical climates.

gas turbine, inlet air cooling, evaporative cooler, mechanical chiller, tropical climate, thermal efficiency, relative humidity

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