Thermo-economic comparison of three configurations of combined supercritical CO2 refrigeration and multi-effect desalination systems

This paper proposed a novel combination of the supercritical carbon dioxide refrigeration and Boosted-multi-effect-desalination system. Comparative study of the combined system and two different modifications of it is performed from thermo-economic viewpoint. Thermodynamic and economical optimization is also carried out for the two modified forms; equipped with the expander and two-stage compression. It is found that an acceptable recovery ratio is gained from the introduced system compared to that of the conventional steam-driven MED. For both modifications, thermodynamic optimization results showed that COP and exergy efficiency improve about 12% and 8% respectively, at the expense of 18% increment in the TAC rate, compared to the optimal economical design case. On the other hand, the most enhancement resulted from the thermodynamic optimization was associated with the case in which the recovery ratio was increased up to 200% compared to that of the economical one. However, the TAC rate for the two compressors modification is 2.2% lower than that of the expander one. While, the first modification would significantly decreases the recovery ratio (about 41%). Finally, by the exergo-economic factor definition, a reasonable decision about the stability between the exergy destruction of the components and their capital investment would be achieved.