International Scientific Journal


This paper presents a new approach in mathematical modeling of thermodynamic cycles and electric power of utility district-heating and cogeneration steam turbines. The approach is based on the application of the dimensionless mass flows, which describe the thermodynamic cycle of a combined heat and power steam turbine. The mass flows are calculated relative to the mass flow to low pressure turbine. The procedure introduces the extraction mass flow load parameter νh which clearly indicates the energy transformation process, as well as the cogeneration turbine design features, but also its fitness for the electrical energy system requirements. The presented approach allows fast computations, as well as direct calculation of the selected energy efficiency indicators. The approach is exemplified with the calculation results of the district heat power to electric power ratio, as well as the cycle efficiency, versus νh. The influence of νh on the conformity of a combined heat and power turbine to the grid requirements is also analyzed and discussed. [Projekat Ministarstva nauke Republike Srbije, br. 33049: Development of CHP demonstration plant with gasification of biomass]
PAPER REVISED: 2012-07-04
PAPER ACCEPTED: 2012-07-12
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THERMAL SCIENCE YEAR 2012, VOLUME 16, ISSUE Supplement 2, PAGES [S399 - S407]
  1. Horlock J. H., Cogeneration - Combined Heat and Power (CHP), Krieger Publishing Company, Malabar, Florida, USA, 1997
  2. Saviæ, B., Computer program TURBOEX for the Computation of Performances of Fossil Fuel Cogeneration Plants with Extraction Steam Turbines, in: Mathematical Modeling and Computer Simulation of Processes in Energy Systems, (Ed. K. Hanjalic), Hemisphere Publishing Corporation, 1991, pp. 815-828
  3. Grkoviæ, V., Simulation stationarer Betriebszustande von Kondensationstrubinen mit Fernwarmeauskoppelung, BWK, 39(1987), 7/8, pp. 349-54.
  4. Grkoviæ, V., Selection of the Optimal Extraction Pressure for Steam from a Condensation-Extraction Turbine, Energy, 15(1990), pp. 459-65
  5. Janicka J. Berechnungsverfahren für Kraftswerksprozesse, BWK 42 (1990), pp.505-13.
  6. Grkoviæ, V., Energy-Efficiency Improvements by Joint Operation of Two DH Systems Using Old Condensing Turbines, Energy, 22(1997), pp.1099-102
  7. Grkoviæ, V., Optimizations for District Heating of Belgrade from the Kolubara Energy and Industrial Complex, Energy, 14(1989), pp. 747-56
  8. Haymow V. A. et al.: Low Flow Rate Regimes and LPT Strength of T-250/300-23.5 District Heating Steam Turbine (In Russian), UDK 621.165.697.34.
  9. Schenck, K, Zorner W.E. Advanced Steam Turbines with Heat Extraction Walsum and Herne Power Plants, in: Cogeneration and Combined Cycle Plants - Design, Interconnection, and Turbine Applications, (Ed. J. W. Schroeder), New York: The American Society of Mechanical Engineers; 1990, pp. 59-67
  10. Grkoviæ, V., Technological Fundaments of Cogeneration Steam Turbines Control (In Serbian), Future Publikacije, Novi Sad, Serbia, 1995

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