In this paper, an experimental and theoretical investigation is performed on a novel water desalination system based on a humidification–dehumidification technique using a heat pump. An ultrasonic water atomizer is used in the humidification process in order to improve the humidification system. In addition to that, a new configuration is employed in the humidification process (hybrid atomization system), which combines the traditional spraying atomization system and the ultrasonic water atomizer. The new humidification system performance is investigated and compared with the spraying water atomizer system in terms of humidification effectiveness and freshwater productivity. The results show that the ultrasonic water atomizer has enhanced and improved humidification effectiveness, and consequently, the productivity of freshwater. The maximum humidification effectiveness and productivity achieved by the ultrasonic water atomizer are 94.9% and 4.9 kg/h, respectively, meaning an increase of 25.2% and 18.8%, compared to the traditional spraying atomization system. The hybrid system increases humidification effectiveness and productivity by 3.8% and 8.2%, respectively, in comparison with the stand-alone ultrasonic water atomizer. A cost analysis was also carried out in this paper in order to perform an economic comparison of different humidification processes (spraying, ultrasonic; and hybrid atomization systems). The minimum production cost of one liter of freshwater amounts to $0.0311 with the spraying system, $0.0251 with the ultrasonic system, and $0.0250 with the hybrid atomization system. These results reveal the profitability of the new configuration.

The pressing demand for clean water worldwide has increased attention to developing innovative desalination processes. In this work, the second law of thermodynamics is used to examine and assess two coupled desalination systems: a separation-based reverse osmosis (RO) system and a thermal desalination-based humidification–dehumidification (HDH) system. The HDH unit configuration used here is based on the working principle of the heat pump, where the process is open-air, open-water, and air-heated. The RO system is equipped with a pressure exchanger (PX) and has been examined under various operating circumstances, such as different feed water pressures, salinities, and flow rates. To improve the system’s sustainability, a solar photovoltaic system (PV) was integrated. An exergy model was used to precisely evaluate the system components and the hybrid systems by employing a proper exergy efficiency definition. The evaluation of the second law of thermodynamics for the RO–HDH–PX and RO–HDH–PX–PV systems indicated maximum efficiencies of 23% and 23.25%, respectively. A cost analysis was also performed on the hybrid RO–HDH–PX–PV desalination system using two approaches: the first included a battery storage system, whereas, in the second, the battery was not considered. When a battery storage system is included, the cost per cubic meter varies from USD 3.22 to USD 5.10. In contrast, it varies from USD 3.96 to USD 7.12 without a battery storage system.

In this research, a simulation and modeling have been carried out for a novel hybrid desalination system. The hybrid system incorporates two methods for desalinating seawater, relying on membrane and thermal techniques. First, the reverse osmosis (RO) system (membrane-based technology) is implemented with energy recovery devices. The second is the humidification-dehumidification (HDH) system (thermal-based technology). The HDH unit configuration leaned on the working principle of the heat pump, where the examined process is open-water open-air air heat (OWOA-AH). The first and second laws of thermodynamics are used to assess the performance of the stand-alone RO, HDH, and the hybrid system, which combines both systems. The study concluded that the RO system could provide 163.5 to 257 kg/h permeate flow, while the HDH could provide 3.34 to 4.76 kg/h. The RO fitted with the turbocharger and pressure exchanger improved system-specific energy consumption by 39.3% and 53%, respectively. However, in the hybrid system, the specific energy consumption showed a signification increase due to the total power consumption of both systems, especially the HDH system. The evaluation of the second law of thermodynamics for the stand-alone RO, HDH, and the hybrid system, indicated a maximum efficiency of 65.68%, 11.92%, and 23%, respectively.