Thermoeconomic analysis of mixed gas-steam cycles

In this paper the direct thermoeconomic analysis approach developed by the authors [ASME Paper 95-CTP-38, ASME Cogen Turbo Power Conference, Wien, 23/ 25 August, 1995] is applied to the assessment of the thermoeconomic perform ance of mixed gas-steam cycles such as the steam injected cycle (steam inje cted gas turbine, STIG), regenerated water injected (RWI) cycle, and humid air turbine (HAT) or evaporative cycle. All the simulations were carried us ing the thermo-economic modular program (TEMP) code developed at the Univer sity of Genoa [ASME Trans., J. Engng. Gas Turbine Power 119 (1997) 885; The rmo-economic and environmental optimisation of energy systems, Tesi di Dott orato, Universita di Genova (DIMSET), 1997] and carefully tested here, main ly for the HAT cycle and saturator, using the experimental data provided by the HAT pilot-plant operating at the Lund University, Sweden [Theoretical and experimental evaluation of the EvGT-process, Thesis for Degree of Licen tiate in Engineering, Lund Institute of Technology, Sweden, 1999; Evaporati ve cycles - in theory and in practice, Doctoral Thesis, Lund Institute of T echnology, Sweden, 2000]. Three different mixed cycles (STIG, RWI, and HAT) are analysed in detail to gether with an additional fourth layout proposed by the authors [Thermoecon omic analysis of STIG, RWI and HAT cycles with carbon dioxide (CO2) emissio ns penalty, Tesi di laurea, Universita di Genova (DIMSET), 2000], named HAW IT, humid air water injection turbine, that appears to be the most attracti ve solution. The thermoeconomic results of mixed cycles are presented here for the first time in open literature. These results are compared to the data of a conve ntional two-pressure level combined cycle considered as representative of t he state of the art of high efficiency conversion systems. A new representa tion proposed by the authors [ASME Trans., J. Engng. Gas Turbine Power 122 (2000)], such as cost of electricity versus cycle efficiency or internal ra te of return versus electric efficiency, is used to demonstrate the main fe atures of these types of innovative energy plants. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.