Efficient direction-independent fog harvesting using a corona discharge device with a multi-electrode structure

Abstract

Efficient collection of water from fog can effectively alleviate the problem of water shortage in foggy but water-scarce areas, such as desert, island and so on. Different with the inefficient fog meshes, corona discharge can release charged particles, charge water droplets and further enhance the water-collecting effect. This manuscript proposes a novel multi-electrode collecting structure, which can achieve the efficient and direction-independent collecting fog. The multi-electrode structure consists of three parts: charging electrode, intercepting electrode and ground electrode. Four types of water-collecting structures are compared experimentally, and the results show that the collection rates of traditional fog mesh, wire-mesh electrode with fog coming from high-voltage electrode (FH), wire-mesh electrode with fog coming from ground electrode (FG) and multi-electrode are 2~3 g/h, 100~120 g/h, 60~80 g/h, 200~220 g/h, respectively. The collection rate of multi-electrode structure is 100 ~ 150 times that of traditional fog mesh and 2 ~ 4 times that of wire-mesh electrode. These results demonstrate the superiority of the multi-electrode structure in fog collection. In addition, the motion equation of charged droplets in electric field is also derived, and the optimization strategy of electrode spacing is also discussed. This structure can be applied not only to fog collection, but also to air purification, factory waste gas treatment and other fields.

Ionic Wind Driven Fog Collection in Windless Environment

“…In previously reported electrostatic fog collectors, meshes ,,, and pillar array , were applied as the collection electrodes. The sensitivity of the fog collection rate to the geometry of the collection electrode is unclear.…”

“…21 Ionic wind generated by the corona discharge process was used to intercept the fog stream and capture fog droplets. 22,23 Corona discharge and cooling have been coupled to harvest the fog and water vapor in the wet flue gas. 24 The deposition efficiency depends on the Stokes number.…”

“…An active fog collection approach by using the corona discharge and electric field has recently attracted much attention. − Droplets in the fog are charged by the corona discharge, and the deposition efficiency can be greatly enhanced (>1.0) by the electric field . A field experiment demonstrated that an electrostatic fog collector provides a 60% better fog collection rate than a standard mesh-like fog collector .…”

“…An overall fog collection efficiency of more than 90% was reported by using pillar arrays as the collection electrodes and wires as the repelling electrodes . Ionic wind generated by the corona discharge process was used to intercept the fog stream and capture fog droplets. , Corona discharge and cooling have been coupled to harvest the fog and water vapor in the wet flue gas …”

Advanced Fog Harvesting Method by Coupling Plasma and Micro/Nano Materials

“…The platform phenomenon is the result of the balance of electric field force, drag force, and resistance of charged droplets. 21,24,37 Figure 5b shows the collection efficiency with various coatings at 14 kV (a typical saturated voltage). It is surprising to find that the collection efficiency of HB/HL is the highest, reaching up to 93%.…”