Techno-Economic Assessment of Hybrid Turbine Inlet Air Cooling (TIAC) Systems for Gas Turbines in Riyadh’s Extreme Climate

Turbine inlet air cooling (TIAC) is a well-established approach for enhancing the performance of gas turbine power plants operating in hot climates. However, single air-cooling methods have shown limitations mainly in harsh and severe climates. In this work, nine hybrid TIAC configurations integrating two different cooling technologies are proposed and systematically analyzed. The hybrid systems are grouped into three main configurations based on the arrangement of evaporative and refrigerated cooling: Configuration I, where media evaporative cooling is followed in series by refrigerated cooling; Configuration II, where refrigerated cooling precedes evaporative cooling; and Configuration III, where both systems operate in parallel and are then mixed. Each configuration is evaluated through thermodynamic and thermo-economic analyses, considering the performance of a typical 85 MW General Electric (GE) PG7121EA gas turbine unit under the harsh climate conditions of Riyadh, Saudi Arabia. Simulations were carried out using the Engineering Equation Solver (EES) software. This study provides a comprehensive framework for selecting hybrid TIAC configurations based on an overall thermo-economic assessment that considers additional power generation, water consumption, and economic performance. The results reveal that all hybrid TIAC systems substantially reduce the inlet air temperature below ISO reference conditions, with Configuration I providing the best overall balance between technical and economic performance. In terms of cost-effectiveness, Configuration II–Hybrid VI (single-effect H2O–LiBr absorption refrigeration followed by evaporative cooling) demonstrates improved economic performance over the standalone single-effect H2O–LiBr absorption system. The findings underscore that hybrid TIAC systems can significantly enhance gas turbine output while achieving favorable payback periods, making them a promising solution for desert climates.