Following methods are used to improve the efficiency of gas turbine power plants.
- Gas turbine cycle with regeneration
- Gas turbine cycle with reheating
- Gas turbine cycle with intercooling
Gas turbine cycle with regeneration:
The temperature at the exhaust of the gas turbine is higher than the temperature of the air at the exit of the compressor. In order to utilize the heat energy of the exhaust of the turbine, which is a waste to the atmosphere, the compressed air is heated in a heat exchanger called regenerator. In a counter flow heat exchanger, it is theoretically possible to heat the air discharged by the compressor reversibly to the temperature of the exhaust leaving the turbine and to cool the turbine exhaust gases equal to the temperature of the discharge of the compressor air.
Gas turbine cycle with reheating
Turbine output can be increased by reheating of the gas during expansion in two or stages. In between the turbine stages, an additional combustors or reheaters are added in order to heat the gases.
Gas turbine cycle with intercooling
As it is known that the majority of the power generated by the turbine is utilized for running compressor, it is important to reduce the compressor power consumption. This can be achieved by compressing the air in two or more number of stages by providing an intercooler in between the stages such that law of compression approaches to isothermal compression.