What is IBH?
IBH is a way to decrease compressor efficiency and reduce mass flow through the compressor. Inlet bleed heat(IBH) takes compressor discharge air and routes it back to the inlet of the compressor. By taking compressor discharge air away from the combustion wrapper you reduce mass available to the combustor. Also introducing this very hot air into the turbine inlet raises the temperature of the air and decreases the efficiency of the compressor since warm dry air has less mass than cold damp air. All of this is typically done to reduce mass flow through the compressor at low load conditions to help control emissions. It also helps to decrease the formation of ice in cold climate areas, and lastly helps to provide compressor protection at low loads, again by reducing the efficiency of the compressor. Inlet bleed heat demand is typically a logrithmic function of IGV angle, although you would be advised to review application code for the particular unit you are familiar with. This descrip