Technical Assessment of Large-Scale PCM Packed Beds for Water-Free Gas Turbine Inlet Air Cooling and Peak Power Enhancement

This study examines the application of large-scale phase change material (PCM) packed beds for compressor inlet air cooling to enhance gas turbine power generation during high-temperature periods. The proposed system employs encapsulated PCM installed in covered underground trenches to provide latent thermal energy storage and maintain an approximately constant inlet air temperature, without the use of water injection. Three PCMs—RT31, RT35hc, and lithium nitrate trihydrate—were evaluated, with lithium nitrate trihydrate demonstrating superior thermal performance and more compact system dimensions. The method was applied to a gas turbine with a rated capacity of 123.4 MW and average capacity of 85 MW. The average air mass flow for this turbine is 281.63 kg/s. The simulation results indicate that the system can increase annual electricity generation by more than 4,700 MWh. Compared with water-based cooling, the PCM system achieves comparable power enhancement while saving approximately 4,300 tons of water annually. Unlike conventional evaporative cooling systems, the proposed PCM packed-bed approach enables water-free compressor inlet air cooling, making it particularly suitable for humid climates where wet- and dry-bulb temperatures are close and for regions experiencing water scarcity.