Employing binary/ternary organic blends in integrated HP-assisted HDH desalination systems

Abstract

The global demand for potable water is rising, prompting the development of various energy systems for distilled water production. However, the significance of utilizing multicomponent working fluids in these systems has been largely overlooked. This study presents three HDH-based distillation units powered by two conventional heat pump cycles, namely, the simple and vapor injection heat pumps (first and second models) and an innovative heat pump cycle with an ejector expander (third model). The significance of the research lies in its pioneering investigation of utilizing two- and three-component mixtures in heat pump-based desalination units, which has not been previously explored. The study's primary aim is to determine whether using multicomponent working fluids instead of pure fluids or introducing structural modifications can more effectively enhance the performance of heat pump-based distillation units. The proposed models are simulated using EES and MATLAB software, with the study focusing on energetic, exergetic, exergoeconomic, and heat exchanger modeling to evaluate the feasibility of the configurations. The findings revealed that the structural modifications in the third scenario using R134a resulted in the highest GOR, with improvements of 44 % and 26.03 %, respectively, compared to the other scenarios. However, utilizing binary blend R22/R142b with different compositions improved the GOR of the first to three scenarios by 41.26 %, 29.06 %, and 11.87 %, respectively. Furthermore, in this case, the unit cost of distilled water for the first, second, and third scenarios increased by 12.87 %, 14.32 %, and 12.70 %, respectively. Finally, the first scenario has the highest NPV of 4.40 M$ and the shortest PP of 8.13 years. Therefore, utilizing the blend in a simple heat pump proves to be more efficient and cost-effective than implementing structural modifications.