Combined absorption desalination-refrigeration cycle driven by low temperature heat source

Combined absorption desalination-refrigeration cycles enable simultaneous freshwater production and cooling through sub-ambient evaporation of saline water, offering promise for regions facing water and cooling shortages. However, conventional single-stage cycles cannot operate effectively under low-temperature heat sources such as solar thermal energy. To address this, we propose heat-coupled and mass-coupled double-stage cycles and conduct performance comparisons with the single-stage configuration. Key indicators—coefficient of performance (COP), gained output ratio (GOR), specific cooling power (SCP), specific water production (SWP), and exergy efficiency—are evaluated across a heat source temperature range of 50–85 °C. Results show that double-stage cycles provide more stable performance under varying conditions. The heat-coupled configuration achieves the best efficiency, with a COP of 0.45 and GOR of 0.91 at 53 °C—the lowest temperature where the single-stage cycle functions, with only 0.029 COP and 0.03 GOR. This represents over a 30-fold increase in water production and more than a 15-fold improvement in COP. Across the full temperature range, the heat-coupled cycle consistently outperforms the single-stage system, with GORs of 0.88–0.92, SCPs of 83.32–751.50 kW/kg, and SWPs of 0.13–1.25. These results highlight its potential as an efficient solution for utilizing low-grade heat to address global water scarcity and cooling demands.