Abstract: A tesla-type turbine for converting the enthalpy of a gas volume flow into mechanical energy, a method for operating the Tesla-type turbine, and an apparatus for converting thermal energy into mechanical energy, a method for converting thermal energy into mechanical energy, and a method for converting thermal energy into electrical energy. The Tesla-type turbine has at least one disc which is positioned on an axis of rotation and is set into rotation by a gas volume flow flowing substantially tangentially, so that mechanical energy can be collected at a shaft coupled to the disc. A disc body that forms the disc has at least one cavity in which, for the purpose of cooling the disc body, a cooling medium, in particular a cooling liquid, is received or can be received.