Gas-steam combined cycle (GSCC) power plants experience significant efficiency losses when inlet air temperatures rise, a challenge that intensifies in arid and tropical regions where ambient temperatures reach extreme levels. To address this issue, researchers have evaluated two inlet air cooling technologies through a comprehensive environmental thermoeconomic cost model that assesses energy efficiency, economic viability, and environmental impact simultaneously.
The study examined absorption refrigeration cooling (ARC) and spray evaporative cooling (SEC) as solutions to mitigate temperature-induced performance degradation. Results indicate both technologies effectively reduce the thermal burden on GSCC systems, but their effectiveness varies considerably based on climatic conditions.
Spray evaporative cooling demonstrated superior cost-effectiveness in arid environments, achieving maximum total environmental cost reductions of 0.64 percent for every 10 percent decrease in relative humidity. This technology leverages the natural evaporative process, making it economical in dry climates where moisture levels remain consistently low. The lower capital and operational requirements of SEC make it particularly attractive for power plants in desert and semi-arid regions.
Absorption refrigeration cooling, while more complex and capital-intensive, proved superior in humid climates, delivering up to 3.6 percent total environmental cost reduction. Its cooling effectiveness increases with rising ambient temperature, providing reliable performance even as conditions worsen. In high-humidity environments where evaporative cooling loses effectiveness, ARC's mechanical refrigeration cycle maintains consistent cooling capacity.
These findings provide power plant operators with evidence-based guidance for technology selection based on local climate characteristics. For utilities in arid regions, SEC offers an economical pathway to maintain efficiency and reduce environmental costs. Conversely, plants in tropical or humid regions benefit from ARC's superior performance and consistent cooling reliability. This research supports strategic capital investment decisions and operational optimization for combined cycle facilities worldwide, particularly in regions experiencing increasing ambient temperatures due to climate change.
