Energy performance analysis of GE-F5 gas turbines at off-design conditions by applying an innovative convergent–divergent system for the inlet air cooling

Abstract

Ambient air temperature increase, in a gas power plant, causes the intake air mass flow rate to be decreased and can have a significant reducing effect on output power and efficiency. To compensate for this reduction, at different climate conditions, various systems can be used to cool the inlet air. To predict the performance of a gas turbine at off-design conditions (by changing surrounding conditions and/or the air cooling method), modeling of the unit performance is required. Due to the high consumption of water and electricity in the conventional cooling systems, in this paper, in addition to introducing an off-design algorithm, governing equations of each cycle elements were inferenced by their characteristic curve. By developing code in MATLAB software, the effect of applying a novel convergent–divergent system on GE-F5 gas units in Yazd Zanbagh power plants was studied. The results show that in a temperature range between 14 and 50 °C, for each degree decrease in ambient air temperature, an approximately 8.99 kW increase in output power can be obtained. The main advantage of this system is the capability of its application in both dry and humid regions. In addition, the refrigerant medium is not required, which makes this system desirable to use in arid areas.