Self-cleaning solar panels and concentrators with transparent electrodynamic screens
A transparent electrodynamic screen (EDS) enables automatic removal of dust to protect and enhance performance of solar collectors and similar components. A pattern of transparent conductive electrodes are deposited over a glass or polymer outer surface of a solar collector, and embedded under a thin, transparent dielectric fluoropolymer film or silicon dioxide coating. When energized by three-phase voltages at frequencies in the range 5 to 20 Hz, the electrodes produce an oscillating electric field and a traveling electrodynamic wave that charges the particles on the surface and exerts coulomb and dielectrophoretic forces to lift the dust from the surface and transport it to an edge of the collector, thereby clearing the screen. The EDS can be incorporated in the collector in an integrated way during manufacture or retrofitted to existing conventional collectors.
1. A film assembly usable to self-remove particles of material deposited thereon, comprising:
a film of transparent material; and
a set of elongated conductive electrodes carried by the film, the electrodes being configured to be connected to a source of electrical power and to generate an electric field across a surface of the film in response thereto, the electric field being of sufficient strength to remove the particles from the surface of the film by electrodynamic action, the electrodes being separated from adjacent portions of the film by a coating of a dielectric material having substantially higher dielectric strength than a dielectric strength of the film to protect against dielectric breakdown during operation.
2. The film assembly of claim 1 , wherein the dielectric material includes a transparent polymer and/or an inorganic transparent film.
3. The film assembly of claim 1 , wherein the transparent polymer is of a material selected from polyurethane, acrylic, or a fluoropolymer.
4. The film assembly of claim 2 , wherein the inorganic transparent film is of a material selected from silica and or silicon nitride.
5. The film assembly of claim 1 , wherein the conductive electrodes of the film assembly are transparent conductive electrodes, and further including a coating of silica disposed between the dielectric material and a surface of the cover of the solar collector for protecting the conductive electrodes.
6. The film assembly of claim 1 , wherein an outer surface of the film assembly has nanotextured topography to trap light and reduce reflection losses.
7. The film assembly of claim 1 , wherein:
a transparent polymer or transparent inorganic film is used for encapsulating the conductive electrodes; and
a primer coating of thin film is used for increasing adhesiveness.
8. The film assembly of claim 1 , wherein the transparent material has two sub-layers, and an outermost one of the sub-layers includes a self-adhesive backing usable to adhere the film assembly to a separate component.
9. The film assembly of claim 8 , wherein the self-adhesive backing includes a pressure sensitive adhesive allowing for placement of the film aided by vacuum lamination on a surface of the separate component.