Thermodynamic Analysis of a New Combined Cooling and Power System Coupled by the Kalina Cycle and Ammonia–Water Absorption Refrigeration Cycle

Abstract

In order to improve the utilization efficiency of low-temperature heat sources, a new combined cooling and power system using ammonia–water is proposed. The system combines Kalina cycle with absorption refrigeration cycle, in which the waste heat of the Kalina cycle serves as the heat source of the absorption refrigeration cycle. The steady-state mathematical model of system is established in detail first, and then the simulation results of design condition are obtained, which show that the thermal efficiency and exergy efficiency can reach 24.62% and 11.52%, respectively. Based on the system design condition, an exergy destruction analysis is conducted and shows that four heat exchangers and the turbine contribute most of the total exergy destruction. Finally, the effects of five key parameters on the system performance are examined, which reveal that within certain ranges, there is an optimal turbine inlet pressure that makes the exergy efficiency maximal. Increasing the ammonia–water temperature at the vapor generator outlet and the ammonia-weak solution temperature at the bottom outlet of the rectification column will reduce the thermal efficiency but raise the exergy efficiency. With the increase of rectification column pressure, both the thermal efficiency and exergy efficiency drop, while the evaporation pressure has an opposite effect on the system performance.