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Go to Editorial ManagerThe efficiency of gas turbine units is highly affected by the variation of ambient temperature. Increasing the ambient temperature decreasing the efficiency of gas turbine. Cooling the inlet air to the compressor of the gas turbine units is an essential and economical technique for improving its efficiency. Al-Rumaila gas turbine power plant was located in Basrah city, Iraq, which is characterized by its hot climates for more than six months during the year. A novel upstream inlet air cooling system was applied and tested for Rumaila gas turbine power plant. This article represents a thermo-economic evaluation of applying upstream inlet air cooling system. The analysis is based on the test results for operating single unit of Rumaila gas turbine power plant using upstream inlet air system for cooling. The test was performed during July of 2019 for 90 minutes of operation period with ambient temperature of 45 °C. The evaluation analysis shows that, the power output increased from 217.71 MW to 250.11 MW during the period test with percentage increase in power by 15%. This increase in power output led to net economic gains is approximately 1000 $/h.
Industrial gas turbines are central to electricity supply in hot-climate countries such as Iraq, yet their actual performance often deviates from design-point values because of high ambient temperatures, part-load operation, and component degradation. This study quantifies the operational, thermodynamic, and exergy performance of a 125 MW-class simple-cycle gas turbine in southern Iraq and identifies the principal sources of performance loss. High-resolution SCADA data (30,912 valid 15-min records) were analyzed over one full year using integrated energy and exergy balances. The unit operated predominantly at 75–90% of ISO-rated power, with an annual capacity factor of 0.41. At 90–100% load, the average net power output was 114.7 MW, the thermal efficiency was 0.321, the heat rate was 11,210 kJ/kWh, and the exergy efficiency was 0.343, corresponding to a 7–9% derating relative to ISO conditions. Thermal efficiency decreased by about 0.095 percentage points for each 1 °C increase in ambient temperature. Exergy analysis showed that the combustor accounted for approximately 59% of total exergy destruction, followed by the turbine (about 15%) and exhaust-related losses (about 21%). The results confirm the strong dependence of plant performance on ambient temperature and load. Near-term improvement should focus on sustained high-load operation and condition-based maintenance, whereas inlet-air cooling and waste-heat recovery should be evaluated in future techno-economic studies.