Effect of Fan Speed on Air Flow Through a Green Wall Module

Green or living walls are active bio-filters developed to enhance air quality. Often, these walls form the base from which plants are grown; and the plant-wall system helps to remove both gaseous and particulate air pollutants. They can be classified as passive or active systems. The active systems are designed with ventilators which force air through the substrate and plant rooting system, therefore the air is purified and filtered through a bio-filtration process which also acts as a natural cooling system. A fan positioned at a central opening on the module’s back face drives air through the medium-plant-roots mix and then onward through the plants’ canopy; and these would help to remove both gaseous and particulate pollutants from the air. Pressure drop across the module, air flow distribution through it as well as the total flow rate have been obtained. The effect of different fan speeds on the total air flow and on its distribution through the module is investigated in this study in order to optimize the energy consumption of the fans whilst maintaining the modules biofiltration efficiency.