Thermodynamic studies of a HAT cycle and its components

• Published in: Applied energy Vol. 89; no. 1; pp. 315 - 321
• Main Authors: Nyberg, Björn, Thern, Marcus
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-01-2012; Elsevier
• Subjects: air; Applied sciences; Circuit design; Cycle analyzis; Cycle performance; electric power; Electric power generation; Electric power plants; Energiteknik; Energy; Energy Engineering; Engineering and Technology; Evaporative; EvGT; Exact sciences and technology; Humid Air Turbine; Intercooler; Makeup water; Maskinteknik; Mechanical Engineering; Optimization; power plants; solar energy; Solar power generation; Teknik; Thermodynamics; Turbine cooling; Water temperature; wind; Makeup water; AC; COT; Cycle performance; ECO; Turbine cooling; Intercooler; HAT; IC; Humid Air Turbine; LHV; Cycle analyzis; EvGT
• ISSN: 0306-2619; 1872-9118; 1872-9118
• DOI: 10.1016/j.apenergy.2011.07.036

► Performance maps for HAT cycles with different complexity are shown. ► A suggestion, where to extract cooling air for the turbine is presented. ► The influence of the makeup water on total efficiency is shown. ► The optimal pressure level for intercooling is described.
The electric power grid contains more and more renewable power production such as wind and solar power. The use of renewable power sources increases the fluctuations in the power grid which increase the demand for highly efficient, fast-starting power-producing units that can cope with sudden production losses. One of the more innovative power plant cycles, that have the potential of competing with conventional combined power plants in efficiency but has a higher availability and faster start up time, is the Evaporative Gas Turbine (EvGT) or Humid Air Turbine (HAT). A thermodynamic evaluation of different HAT cycle layouts has been done in this paper. Each layout is evaluated separately which makes it possible to study different components individual contribution to the efficiency and specific power. The thermodynamic evaluation also shows that it is important to look at different cool-flow extracting positions. The effect of water temperature entering the cycle, called make-up water, and where it is introduced into the cycle has been evaluated. The make-up water temperature also affects the optimal pressure level for intercooling and it is shown that an optimal position can be decided considering design parameters of the compressor and the water circuit.