Analysis of heat-driven combined cooling and desalination

This paper investigates the opportunities for integrating thermally driven cooling systems with thermally driven desalination systems via cascade of reject heat. Single- and double-stage ammonia-water (NH₃-H₂O) absorption refrigeration systems with multi-effect distillation (MED) are selected for this study based on technical limitations and practical considerations. Cooling capacity and hourly water production are calculated from thermodynamic properties of the working fluids at different operating conditions using simple models for each of the constituent systems. Additionally, the second law of thermodynamics is applied with the aim of examining the entropy generation of each component as well as the total exergy destruction of the entire system. The results indicate that the total exergy destruction of the combined systems, which consist of an MED unit driven by either a single- or double-stage NH₃-H₂O refrigeration system, decreases by an average of 55% compared to stand-alone NH₃-H₂O and MED systems. Relative to stand-alone systems, although water production decreases by 30% and 9% when an MED unit is integrated with single- and double-stage NH₃-H₂O absorption systems, respectively, cooling capacity remains unchanged for the double-stage NH₃-H₂O-MED system, and only decreases by 16% for the single-stage NH₃-H₂O-MED system.