Energy, exergy and economic analysis of a new power generation system based on Kalina cycle and absorption refrigeration cycle for low-temperature heat source recovery

Kalina cycle is one of the most promising power cycles that utilizes mid- and low-temperature heat sources, but the performance of the basic configuration of Kalina cycle still needs to be improved. In this article, an absorption refrigeration cycle is proposed to couple with the Kalina cycle, thus forming a new power generation system, in which the waste heat of the heat source and the Kalina cycle are recovered for producing cooling capacity to drop the turbine back pressure of Kalina cycle, leading to an increase in the turbine power output. Thermodynamic and economic models are established for the system, based on which the design operating conditions of the system are calculated. Then, the effects of eight key parameters on the system performance are investigated by parameter sensitivity analysis. Finally, an optimization is conducted for the system to obtain its optimal performance, and the purchase cost and exergy destruction distributions in the system are analyzed. The results show that in the case of a heat source of 200 degrees C flue gas, the proposed system could reach 9.56% thermal efficiency and 31.44% exergy efficiency; meanwhile, the payback period of system is only about 7 years.