Energy, exergy, economic, and environmental (4E) analysis of gas turbine performance enhancement through inlet fogging across different climate zones

Generally, gas turbines have been sensitive to ambient conditions, mainly temperature and relative humidity, which alter their efficiency, power output, fuel consumption, and environmental emissions. The present study performs a detailed energy, exergy, economic, and environmental (4E) analysis of the effect that an inlet fogging system will have on a gas turbine operating in three different climate zones: Shiraz (hot and dry), Ghazvin (cold and dry), and Neka (moderate and humid). The results demonstrate that the fogging system increases power output relative to the climatic zone. The most significant increase of up to 4.5 % was observed in Shiraz (hot & dry), then Neka (moderate & humid), where the increase was 3.6 %, and Ghazvin (cold & dry), where the power output increased by 2.7 %. The thermal efficiency also improved by 2.3 % points in Shiraz, 1.9 points in Neka, and 1.5 points in Ghazvin. From the exergetic analysis, it was concluded that exergetic efficiency improved by 12.3 % in Shiraz, 9.8 % in Neka, and 7.2 % in Ghazvin, all from the contribution of the fogging system, particularly through a reduction of exergetic destruction across the compressor and turbine. Economically, the fogging system had large fuel cost savings ranging up to $2.1 million in Shiraz, $1.4 million in Neka, and $0.85 million in Ghazvin, where ROI was 158 % in Shiraz, 102 % in Neka, and 72 % in Ghazvin. In addition, the payback period was quickest with 0.9 years in Shiraz, 1.2 years in Neka, and 1.6 years in Ghazvin. Environmentally, the fogging system had a CO₂ reduction of ∼ 61,875 metric tons/year in Shiraz, ∼43,200 metric tons/year in Neka, and ∼ 18,900 metric tons/year in Ghazvin, while water usage was achieved within sustainable levels in all three locations. These results conclude that fogging is most effective in hot and dry climates, with substantial gains in efficiency, power output, and sustainability, while in humid and cold climates, its economic and environmental viability remains moderate. The study gives critical insights into the optimization of turbine performance under varying climatic conditions for both power plant operators and policymakers.