binary fluid, ejector, COP, solar, dessalination
The proposed desalination technology represents the combined processes of distillation and congelation of seawater. While distilling runs at two-stage, the condensation heat of the distillate vapors is utilized for cold generation in the Binary Fluid Ejector Refrigeration System (BERS). The congelation process is organized with continuous heat recuperation that enables to mark up about 80% of the fresh water, produced by BERS. The system tolerates any type of seawater (30k ≤ TDS ≤ 100k) and operates with solar thermal heat of 338-356F. The integrated binary fluid ejector heat pump doubles the input of thermal energy at 248F, so the overall output fresh water efficiency is 9 times higher compared to the single stage distillation. This technology represents the novel, economically viable, unrivalled approach that is free from disadvantages typical for most of existed desalination systems. The most efficient flat plate vacuum solar collectors are selected for the study of the integrated solar desalination system. Extensive thermodynamic analysis of the system performance and experimental validation of the results are the core research and development efforts. The main component to operate the solar thermal congelation process is BERS using a binary mixture of low-boiling point refrigerants as the driving fluid of the system. The recent research and experimental studies on utilization of the low-boiling point refrigerants in the ejector-based systems resulted in the 30-50% improved efficiency compared to steam-driven ones, however, it only allowed the ejector systems to become competitive with the other types of the low-grade heat operated heat pumps, such as absorption and adsorption technologies. The application of binary fluids in the ejector-based cooling systems has boosted the energy efficiency as much as 80-120% that potentially makes the binary fluid ejector system the most advanced thermally-driven heat pump ever created. The binary fluid application in BERS allows energy losses reduction by decreasing the velocity difference between working and refrigerant fluids. Binary fluid systems unlike single fluid ones perform a power cycle with a working fluid, that consumes relatively less heat, while the reverse cycle is performed by the most efficient refrigerant fluid, which removes 2-3 times more heat from the low temperature source per refrigerant fluid unit mass. It is important to achieve the maximum entrainment ratio and the lowest ratio of the specific cooling capacity to the specific heat consumption. The contact between primary flow and the secondary flow in the ejector is required for kinetic energy and momentum transfer, which results in both fluids mixing and thereafter requires the formed binary fluid separation by the single components. In order to separate the flows, it is necessary to condense high temperature fluid (working fluid) in fractionating condenser, where, as a result of heat and mass transfer, the concentration of working fluid increases in liquid phase and refrigerant fluid - in vapor phase.