Performance improvements of the intercooled reheat regenerative gas turbine cycles using indirect evaporative cooling of the inlet air and evaporative cooling of the compressor discharge

Abstract

Inlet air cooling and cooling of the compressor discharge using water injection boost both efficiency and power of gas turbine cycles. An innovative method of cooling the inlet air (indirect evaporative cooling) is introduced. Six different layouts of the intercooled reheat regenerative gas turbine cycle are presented. Those layouts include the effect of different methods of inlet cooling and evaporative cooling of the compressor discharge (evaporative aftercooling). A parametric study of the effect of turbine inlet temperature, ambient temperature and relative humidity on the performance of all six layouts is carried out. The results indicate that as the turbine inlet temperature increases the optimum pressure ratio increases by 1.5 per 100 K for the regular intercooled reheat regenerative cycle and by 4.2 per 100 K for the intercooled reheat regenerative cycle with evaporative aftercooling. The cycles with evaporative aftercooling have distinctive patterns of performance curves and higher values of optimum pressure ratios. The results also show that indirect evaporative cooling of the inlet air could boost the efficiency by up to 3 per cent, which is 1 per cent higher than the direct evaporative cooling method and that evaporative aftercooling could increase the efficiency by up to 5 per cent.