Improved modelling for ammonia-water power cycle coupled with turbine optimization design: A comparison study

The ammonia -water power cycle is one of the most promising power cycles for emission -free heat source utilization and distributed combined systems. In relative literature, the turbine efficiency, which directly and significantly influences the system performance, is assumed to be constant. However, this assumption may lead to inaccurate sensitivity analyses as well as suboptimal designs. In order to enhance the accuracy and reliability of analyses and optimizations of the ammonia -water power cycle, this paper proposes a comprehensive model that incorporates a one-dimensional turbine optimization design model, enabling more accurate and reliable energy, exergy, economic, and environmental (4E) analysis of the cycle. To evaluate the improvement and provide insights into how earlier analyses can be interpreted, the proposed model is applied in 4E analyses of a Kalina cycle and results are further compared with those obtained from the conventional model. The comparison shows deviations of up to 26 % and identifies an appropriate constant turbine isentropic efficiency that yields relatively low error for the conventional model. Additionally, two environmental indicators, namely specific global warming potential and specific environmental impact potential, are proposed for power cycles utilizing emission -free heat sources to compare environmental performance between cycles with different power outputs and configurations.