Investigating the effect of various working fluids in cascade refrigeration cycle integrated with thermal desalination system

Regarding the energy and potable water crisis and many environmental problems due to the use of fossil fuels, it is necessary to utilize the waste heat of industrial equipment to produce potable water without using another energy source.In the present work, a three-effect distillation desalination system is combined with a cascade refrigeration cycle. On the other hand, the effects of various working fluids in the cascade refrigeration cycle were investigated and evaluated on the indicators such as the mass flow rate of potable water, the occupied space of the integrated system, the power consumption of compressors, and the related investment cost. Along with comparing the 28 working fluid pairs, a scoring method was used to determine the best working fluid pair due to the different scenarios and priorities. The results showed that the lowest power consumption of compressors belongs to R600-R717 working fluid pair. Moreover, the highest mass flow rate of produced potable water, the lowest occupied space and the lowest related investment cost happen when R744-R600A is considered. Using the scoring method, it was determined that when all indicators are considered for selecting the working fluid pair, even in different scenarios with different priorities, the best choice is R600-R717.