Why Kalina (Ammonia-Water) cycle rather than steam Rankine cycle and pure ammonia cycle: A comparative and comprehensive case study for a cogeneration system

Abstract

There are many studies on the Kalina cycle and steam Rankine cycles. However, there are not enough comparative and descriptive studies on why the Kalina cycle or steam Rankine cycle should be selected. In addition to that, almost there are no papers on why Kalina cycle and steam Rankine cycle are commonly used systems rather than the pure ammonia cycle. For these reasons, the present paper was designed, analysed and compared comprehensively the Kalina, steam Rankine and pure ammonia cycles as a subsystem for use in a cogeneration cycle. Moreover, the pure ammonia cycle system was analysed for both simple and regenerative designs to comprehensively present all cases. After deciding the best cogeneration system configuration for the present system, the economic and environmental analyses of the best performing system were performed. In addition to all these, during the study, the condensing temperature remained constant to be able to analyse systems in line with real working conditions. As a result of the comprehensive analyses, the Kalina cycle showed the best performance. The maximum net power, thermal and exergy efficiencies of the Kalina cycle were calculated at ammonia-water concertation of X = 25% and a turbine inlet temperature of t = 340 °C as 365.92 kW, 25.52%, 57.96% respectively. Thanks to the power generated by integrating the Kalina cycle into the system, 244.53 kg-CO2/h carbon dioxide was reduced and the total cost of the Kalina cycle and the payback period was found as 343,975.26$ and 2.2 years. The maximum thermal and exergy efficiencies of the Kalina cycle-based cogeneration system were calculated as 72.13% and 78.60%.