Limitations of Inlet Air Evaporative Cooling System for Enhancing Gas Turbine Performance in Hot and Humid Climates

This paper aims to investigate the evaporative cooling limitations of compressor intake-air for improving the performance of gas turbine power plants. The limitations of the evaporative cooling capability are analyzed and formulated in terms of the characteristic dimensions involving the temperature ratio, the power gain ratio (PGR), thermal efficiency change, and humidity ratio. The effects of different pressure ratios (PRs) are examined for Saudi Arabia summer weather when the turbine inlet temperature is predetermined at1373.15 K. The results of a specific example where the air evaporative cooler drops the temperature to the wet bulb temperature are presented. These indicate that the power gain ratio enhancement depends on the ambient temperature, relative humidity, evaporative cooler effectiveness, and slightly the PR. Especially for PR =10, the PGR is enhanced by 9% at 20% of relative humidity and dropped to 3.37% at 60% of relative humidity. The daily performance of the evaporative cooling method is examined for the hot humid conditions of Jeddah, Saudi Arabia. The results show that the evaporative cooler increased both the daily power output and the thermal efficiency by 2.52% and 0.112%, respectively.