The Installation & Testing of the Fog Inlet Air Cooling System for the Yazd Combined Cycle Power Plant

Abstract

Gas turbines are almost constant volume machines at a given constant shaft speed. On the other hand, the gas turbine output power depends strongly on the inlet air mass flow rate. Therefore, the available output power considerably reduces when the air density decreases at high ambient temperatures. The solution of this problem is very important because the peak demand season also happens in the summer. In Iran, various inlet air cooling systems are used in power plants to overcome this problem. In this paper, the different inlet air cooling systems are reviewed and the fog system is selected as the best alternative for the Yazd combined cycle power plant. This system is installed and commissioned in Yazd power plant in the spring of 2006. The test results of this system at 38 and 7% relative humidity have shown an average power increase of 10.6 MW (11.8%) for the gas turbine No.1 and 10.9 MW °C (12.1%) for the gas turbine No.2. The economical study has shown that this system is very cheap in comparison with the installation of new gas turbines.