Thermo-Economic Analysis and Multi-Objective Optimization of DEVAP Cooling System in a Gas Turbine

The most significant factor which affects thermal efficiency in gas turbines is climate condition. Studies showed that decreasing inlet air temperature will result in enhancing gas turbine thermal efficiency. Evaporative cooling, which is commonly used as an inlet air cooling technique, is not applicable in humid climates. Implementing desiccants to dehumidify the inlet air will enhance evaporative inlet cooling efficiency in humid climates. A thermo-economic analysis and optimization of a desiccant-enhanced evaporative cooling system in gas turbine is performed in this paper. The optimum values of main parameters such as inlet air temperature and velocity, mass flow rate of working air, mass flow rate of desiccant, geometrical dimension of the working channel and efficiency are evaluated using multi-objective optimization method. The results showed that for the optimized values of inlet air velocity, dimensionless length, WAR (working to inlet air ratio), cooler’s length, width, height and threshold temperature which were ۲.۱۴۹ m/s, ۴۴۰, ۰.۲۷۵, ۱.۱۷۰ m, ۱۴.۵۹۰ m, ۵.۴۳ m and ۰.۱۱ °C, respectively, the value of AANP and efficiency increase ۴% (۲.۰۶۶ MW) and ۰.۲۵% compared to the base condition. Additionally, the payback period was ۳.۴۷ years which indicated that the improvement project is feasible.