Power generation from gas turbines is penalised by a substantial power output loss with increased ambient temperature. By cooling down the gas turbine intake air, the power output penalty can be mitigated. The purpose of this paper is to review the state of the art in applications for reducing the gas turbine intake air temperature and examine the merits from integration of the different air-cooling methods in gas turbine based power plants. Three different intake air-cooling methods (evaporative cooling, refrigeration cooling and evaporative cooling of pre-compressed air) have been applied in two combined cycle power plants and two gas turbine plants. The calculations were performed on a yearly basis of operation, taking into account the time-varying climatic conditions. The economics from integration of the different cooling systems were calculated and compared.

Background: Power generation from gas turbines is penalized by a substantial power output loss with increased ambient temperature. By cooling down the gas turbine intake air, the power output penalty can be mitigated. Method of Approach: The purpose of this paper is to review the state of the art in applications for reducing the gas turbine intake air temperature and examine the merits from integration of the different air-cooling methods in gas-turbine-based power plants. Three different intake air-cooling, methods (evaporative cooling, refrigeration cooling, and evaporative cooling of precompressed air) have been applied in two combined cycle power plants and two gas turbine plants. The calculations were performed on a yearly basis of operation, taking into account the time-varying climatic conditions. The economics from integration of the different cooling systems were calculated and compared. Results: The results have demonstrated that the highest incremental electricity generation is realized by absorption intake air-cooling. In terms of the economic performance of the investment, the evaporative cooler has the lowest total cost of incremental electricity generation and the lowest payback period (PB). Concerning the cooling method of pre-compressed air, the results show a significant gain in capacity, but the total cost of incremental electricity generation in this case is the highest. Conclusions: Because of the much higher capacity gain by an absorption chiller system, the evaporative cooler and the absorption chiller system may both be selected for boosting the performance of gas-turbine-based power plants, depending on the prevailing requirements of the plant operator.

The purpose of this work is to investigate the benefits of some different ambient air conditioning methods for reducing the gas turbine intake air temperature in order to enhance the gas turbine power. As a reference case the combined heat and power plant of the campus area of the Technische Universita¨t Mu¨nchen in Garching is considered, which is equipped with an Allison KH501 Cheng Cycle gas turbine. Three novel technical possibilities of ambient air cooling and power augmentation are shown in detail (desiccant dehumidification and evaporative cooling, absorption chiller unit with air cooler, evaporative cooling at increased inlet air pressure). Based on site ambient conditions and measured yearly load lines for heat and electrical power connected with actual cost functions, the potential economic savings are worked out for the different technical modifications using ambient air cooling for power augmentation of the gas turbine plant. The economic operation lines for power and heat, supplied by the modified gas turbine plant, are calculated by a cost optimization system. The results are compared based on investment costs and economic savings by the extended annual electrical and thermal power production of the modified gas turbine plant.