Energy, exergy, exergoeconomic and exergoenvironmental analysis on a novel parallel double-effect absorption power cycle driven by the geothermal resource

Abstract

This paper proposes a novel parallel double-effect absorption power cycle using lithium bromide-water solution to make better use of the geothermal source. The comprehensive energy, exergy, exergoeconomic and exergoenvironmental models of this system are developed, and the comparative studies on the thermodynamic, exergoeconomic and exergoenvironmental performance of this system and the traditional absorption power cycle are conducted to reveal the superiority of this system. Besides, the parametric analysis of this system from the exergetic, exergoeconomic and exergoenvironmental viewpoints are performed to determine the effect of the decision parameters on the system performance. The results show that the proposed system driven by geothermal resource can enhance the net power output by 41.3% as well as the exergy efficiency by 12.31% and meanwhile reduce the total product unit cost by 10.12% with slight increase of 1.99% in the total product unit environment impact, compared with the traditional absorption power cycle. In addition, the absorber and the low-temperature generator provide the highest exergy destruction and loss rate with the lowest device exergy efficiency. Moreover, both the highest overall cost rate and the maximum overall environmental impact rate belong to the absorber, followed by the high-temperature turbine. Besides, the operation conditions of this system can be rectified by searching optimal high-temperature turbine inlet pressure or enhancing the high-temperature turbine inlet temperature and the pressure ratio as well as the low-temperature turbine inlet temperature or reducing the absorber outlet temperature and the lithium bromide mass fraction to improve the energy, exergy, exergoeconomic and exergoenvironmental performance of the proposed system.