Energy, exergy, economy and environmental (4E) analysis and optimization of single, dual and triple configurations of the power systems: Rankine Cycle/Kalina Cycle, driven by a gas turbine

Abstract

Improving the overall efficiency of a present power system has significant importance as much as developing renewable energy systems. Because, there are many constructed power systems, which damages the environment by releasing a considerable amount of heat to the environment without use. Therefore, in the present paper, probable single, dual and triple system configurations were assessed in terms of energy, exergy and environment. In the concept of the study, a present gas turbine (GT) cycle was used as topping cycle, while the Rankine cycle (RC) and Kalina cycle (KC) were used as the bottoming cycle. For each single, dual and triple systems, the parametric optimisation of the cycles was made to find best performing system working parameters, in addition to finding probable maximum overall performances. After comprehensive analyses, recoverable heat was found as 30.74% for using single RC and 24.99% for using single KC. By designing a dual system using GT as a topping and RC as a bottoming cycle, the thermal efficiency was calculated as 41.72%. Moreover, it was concluded that 46.39% of total heat input could be recovered by the triple GT-RC-KC. By recovering the heat with these power system configurations, the maximum net power production amounts were found as 1746.80 kW with single RC, 890.14 kW with single KC, 7946.82 kW with dual GT-RC and 8836.96 kW with triple GT-RC-KC. With dual RC-KC configuration integrated to the GT, nearly 1687 tones-CO2/h reduction in CO2 emission amount was achieved. Payback periods of the RC, KC and RC-KC subsystems integrated to the GT were determined as 3.48, 3.22 and 3.39 years, respectively.