Comparative energy, exergy, economic, and environmental (4E) analysis and optimization of two high-temperature Kalina cycles integrated with thermoelectric generators for waste heat recovery from a diesel engine

Abstract

High-temperature Kalina cycles are among the efficient approaches to recovering waste heat. However, high-temperature Kalina cycles are characterized by complex layouts, lower efficiency, and higher cost. This work aims at conducting a comparative thermodynamic, economic, and environmental assessment of two different configurations of the high-temperature Kalina cycle. Thermoelectric generators, as the simple and developing heat recovery modules for electricity generation, have been embedded in the condensers of the simple High-temperature Kalina cycle, thereby proposing the enhanced thermal performance of the Kalina cycles. A parametric optimization approach was adopted to optimize the net power output and the location of pinch points of condensers. The results indicate that thermoelectric generators can improve the total power capacity of High-temperature Kalina cycles by about 0.29–0.82 kW. Meanwhile, the economic feasibility of this integration has also been investigated. The first enhanced Kalina cycle has energy and exergy efficiencies of 32 % and 63.23 %, respectively. As an economic parameter, the net present values of these cycles are 84.56, 84.77, 86.63, and 86.84 k$ for standard Kalina cycle configuration 1, enhanced Kalina cycle configuration 1, standard Kalina cycle configuration 2, and enhanced Kalina cycle configuration 2, respectively. In addition, the environmental assessment reveals that 15.55, 15.85, 15.54, and 15.84 lit/hr diesel fuel would be saved by operating the waste heat recovery cycles, respectively. Finally, a parametric study has been carried out to study the influences of variations of different parameters on the performance criteria of all four cycles.