Method to cool at least a turbine stage and/or at least a combustion chamber, turbine plant and gas and steam turbine plant.

The method for the cooling of at least one turbine stage (5) and/or at least one combustion chamber (3) of a turbine is by the application of cooling fluid under pressure which at least in part is supplied from a system (11) for the producing of a fluid under pressure which is not a component part of the turbine. Nitrogen from an air separation plant is used as the cooling fluid. A part of the cooling fluid not required for the cooling of the turbine stage and/or combustion chamber is supplied for the combustion in the combustion chamber. Independent claims are also included for the following: (A) a turbine installation, especially a gas turbine installation, using a fluid under pressure for cooling purposes; and (B) a combined gas and steam turbine plant incorporating the aforesaid gas turbine installation.