## 2 Proposed Smart Farm Structure: Overall System--Inflatable Aeroponic Enclosed Smart Farm
### Water Circulation System '2, 3, 4'
#### 2.2.2 Misting System '3'  
The Misting System is a pivotal component of aeroponic hydroponics, designed to supply plant roots with fine water droplets. This system integrates pipes fitted with nozzles that directly spray nutrient solutions produced by the Nutrient Mixer onto the roots. This method uses relatively less water compared to traditional hydroponics, significantly reducing water load. Despite its low water usage, the overall water consumption of the system remains high, and it faces technical challenges such as nozzle clogging, nozzle stability, and the ability to evenly distribute mist across the roots. Consequently, further research and development are crucial to enhance the efficiency and performance of the Misting System.  
This study introduces a misting system integrated with 'dry fog' technology within an inflatable enclosed smart farm. 'Dry fog' refers to an ultra-fine mist with particle sizes of less than 10 um, capable of remaining airborne for an extended period. This characteristic allows for achieving uniform distribution using fewer nozzles than traditional aeroponic systems, thus resolving issues related to the overuse of nozzles and simplifying the overall system. Two technological approaches to generating 'dry fog' were considered: the first uses an air- and water-driven two-phase (fluid dynamics) nozzle spray method, and the second employs ultrasonic transducers to create and dispense mist.  
Two-Fluid Nozzle Spray  
The study employs a two-phase nozzle spray system, commonly used in industrial settings for dust removal and in agriculture for pest and disease control [42]. As illustrated in Figure 5, these nozzles operate by generating a mist through the supply of water at low pressure under a constant air pressure setting [43]. Installed within the inflatable enclosed smart farm's cultivation area, this system explores the efficacy and potential improvements of using 'dry fog' mist for cultivation. By maintaining uniform and continuous humidity conditions within the growing environment, the system optimally hydrates plant roots, significantly enhancing the efficiency of hydroponic farming.  
Figure 5: Installation of atomizing nozzles in the cultivation tier of the air-structure smart farm frame. The **top-left** image shows the overall system design with water tanks and misting infrastructure. The **top-right** image captures the installed atomizing nozzles. The **bottom-left** image displays the cultivation area with plants. The **bottom-right** image illustrates the dry fog environment created by the atomizing nozzles.  
The study incorporates an ultrasonic transducer misting technique that uses high-frequency vibrations to finely atomize water, creating a 'dry fog'. This 'dry fog' inherently lacks fluidity, and as depicted in Figure S6, a flow fan was installed in the chamber where the 'dry fog' forms to use the fan's aerodynamics to convey the fine mist into the cultivation beds. To ensure uniform distribution of the mist within the cultivation area, gas guide tubes were utilized, and their effectiveness was experimentally assessed. The used 8 mm polycarbonate pipes span 5.6 m, equipped with 65 outlets, with each outlet's angle adjusted to achieve the optimal spray pattern. Fluid dynamics analysis was simplified using ANSYS software (2024 R1). The cultivation experiments conducted with the ultrasonic transducer misting system installed in the air-structure frame beds demonstrated differences in bed performance depending on the presence or absence of the guide tubes.