Atmospheric water recovery (AWH) is a promising solution to overcome the shortage of clean water in arid regions, especially highland and desertified areas. There are many solutions to recover water from the atmosphere, such as absorption, adsorption, and various condensation-based technologies (condense and recover water), such as fog nets. These nets will retain water droplets when fog passes through, and using good hygroscopic materials, they will then recover water in the moisture-retaining materials. The solution of direct condensation of water vapour by creating cold surfaces with low temperatures also emerges as a promising option for energy savings. This paper presents the calculation process for selecting suitable equipment to build a model of an air-water separator with a compressor power of 1 HP. The study focuses on the influence of air velocity on the water condensation process on the surface of an evaporator with a vertical, smooth-tube condensing surface. The system’s test results were obtained under different operating modes, including the surface temperature of the evaporator changing in response to the speed of change in air humidity conditions, which were approximately 45% in Hanoi, Vietnam. The experiment demonstrates that the system can operate effectively and separate water efficiently in a relative humidity condition of roughly 45%, which is a limitation of other systems. The results of this study also serve as the basis for future research into building larger-scale systems.