Performance Characteristics of Indirect-Fired Gas Turbine/Cogeneration Cycles

Abstract

General characteristics equations for cogeneration cycle thermodynamic performance were derived and expressed as functions of the power-to-heat ratio. Based on these equations, design point performance of indirect-fired open-cycle and closed-cycle gas turbine/cogeneration systems were analyzed and compared with those of steam turbine/cogeneration system. Effects of gas turbine pressure ratio and inlet temperature on design point performance were evaluated. Off-design partial load performances of the three cogeneration systems using various control modes were also investigated. Results indicated significant efficiency advantage of the closed-cycle gas turbine/cogeneration system over the others for both design and off-design operations.

Thermodynamic Study of an Indirect Fired Air Turbine Cogeneration System With Regeneration

“…It is however essentially independent of regenerator effectiveness. This optimum ratio, in the range of 6 to 8, may be approximated as the optimum pressure ratio for maximum power output which is in agreement with the results of Lee (1982).…”

“…Because each of the pressure drop factors is close to unity, equation (18) implies that T)is essentially independent of pressure drops in cycTe? Pt Equation (18) could be useful in the system design stage as it has been shown by Lee (1982) that optimum compressor compression ratio for a regenerative gas turbine cogeneration system is close to that for maximum power output.…”

Fired Heater Versus CCGT/Cogeneration Cycle Parameters

“…The influence of CCGT cycle pressure ratio on the fuel utilization efficiency of cogeneration systems is discussed at length in Ref. 3. As demonstrated therein, the optimum pressure ratio for fuel utilization efficiency, with air working fluid cycles, is typically found between 6 and 10.…”

A Conceptual Design for a Combined Cycle Power Plant Comprising Modified Exhaust-Heated Gas Turbine and a Steam Turbine Plant: Part I — Preliminary Calculations, Basic Dimensions and General Design Conception

“…In the meantime, however, a number of theoretical articles were published in which the authors analysed the most important features of a simple exhaust-heated cycle (open cycle arrangement with indirect firing), the system being treated either as an independent one, meant for production of electricity, or as a more complex system, meant for simultaneous production of steam and electricity. Some of these articles, which ought to be mentioned, are: Huang and Egolfopoulos (1985), Huang and Naumowicz (1987), Huang and Wang (1987), Huang (1991), Lee (1982), Mills and Peltier (1980) and besides a patent by Eberhardt et al (1988), describing a control system of an Indirect Heated Gas Turbine should also be mentioned. Accidentally, almost at the same time the author (1990) resumed some theoretical investigations into the possibilities of practical application of a modified exhaust-heated cycle comprising four sets of turbines and four sets of compressors (with reheat and intercooling) which is different from the commonly analysed simple exhaust heated cycle.…”