Another concept that is being studied is the humidified air turbine (HAT) cycle. This is an intercooled, regenerated cycle with a saturator that adds a considerable amount of moisture to the compressor discharge as shown in Fig. 1.20. The combustor inlet contains 20-40% water vapor, depending on whether the fuel is natural gas or gasified coal gas. The intercooling reduces the compressor work, while the water vapor in the exhaust gases increases the turbine output. Capital cost is lowered by the absence of steam turbine and condenser system. The gas

Turbine combustor design is modified to handle the large amount of water vapor in the incoming air. Cycle efficiency is expected to be in the range of 55% LHV with a significant increase in power output.