Gas turbines with heat exchanger and water injection in the compressed air

In gas turbine plants with heat exchanger, water injection into the compressed air between the compressor and the heat exchangeronly marginally increases the efficiency but it substantially raises output, regarded from the point of view of energy economics, by as much as 55% in two-shaft plants. The specific cost is thus reduced as compared with simple gas turbines without heat exchanger. Regulation of the water supply presents no dlfficulty. The transient behavior is discussed. The addition of water to the cycle reduces the emission of nitrogen oxides by at least half. (auth)