Evaporative Cooling of Gas Turbine Engines

There are numerous gas turbine applications in power generation and mechanical drive service where power drop during the periods of high ambient temperature has a very detrimental effect on the production of power or process throughput. Several geographical locations experience very high temperatures with low coincident relative humidities. In such cases media evaporative cooling can be effectively applied as a low cost power augmentation technique. Several misconceptions exist regarding their applicability to evaporative cooling, the most prevalent being that they can only be applied in extremely dry regions. This paper provides a detailed treatment of media evaporative cooling, discussing aspects that would be of value to an end user, including selection of climatic design points, constructional features of evaporative coolers, thermodynamic aspects of its effect on gas turbines, and approaches to improve reliability. It is hoped that this paper will be of value to plant designers, engineering companies, and operating companies that are considering the use of media evaporative cooling.