Optimal Design of Air Treatment for an Adsorption Water-Harvesting System

In some areas where access to water is difficult, such as arid regions, it is a feasible measure to acquire water from the air. In this context, a system for water harvesting from the air was designed and manufactured. In order to find the optimal operation parameters of the system, the humidity-enthalpy diagram and the dehumidifier computation software (V2.0, Win7) were adopted for the optimization work. The air treatment process of the system was analyzed and calculated by using the professional software provided by the dehumidifier company. Operation modes of 'powerful mode' and 'economic mode' were defined in the computation work, which are represented by the water production amount and efficiency (water production per power consumption), respectively. According to computation analysis, the relationships between the main performance indicators and the system design/operation parameters were obtained. By considering the heating power limitation of the system, the wheel dehumidifier rotation speed of 8 rph (revolutions per hour), zonal area ratio of Ap/Ar = 2, and the optimal airflow ratios in different relative humidity (RH) environments, together with the outlet air parameter settings of the surface cooler, were finally defined.