SUMMARY

As global population and worldwide quality of life continue to increase, available freshwater resources will no longer be sufficient to meet the water needs of humanity. This necessitates the exploration of novel water sources. Many of these have been explored, with a large focus on desalination systems, including multi-stage flash, multi-effect distillation, and reverse osmosis; however, one challenge inherent in the exploitation of alternative water resources is the energy cost of producing that water. By combining water purification with cooling, investigators have sought to create systems that can produce pure water with a low energy penalty. Although these systems are a step in the right direction, they suffer from low water purification rates and in the case of adsorption heat pumps, large system footprints. In this work, a novel water-purifying absorption heat pump cycle is developed by converting a conventional absorption heat pump from a closed-loop cycle to an open-loop cycle. By adding water purification to the cycle, the total utility of the cycle can be increased by up to a factor of two compared to a cycle that only produces cooling. LiBr is selected as the absorbent for the cycle based on thermodynamic and heat transfer studies. A heat exchanger that can serve as the absorber or desorber of a cycle with a nominal cooling capacity of 300 W and a water purification capacity of 10.5 kg day-1 is designed using a detailed heat and mass transfer model, and batchwise experiments are conducted using this heat exchanger to demonstrate water purification and cooling using absorption heat pump cycle components. 90% removal of contaminants from synthetic graywater and 99% removal of salt from simulated seawater are demonstrated.