Solar Collector with Hydrophilic Photocatalytic Coated Protective Pane

Abstract

A solar collector which is illuminated by the sun through a glass panel wherein the glass panel is constructed of glass without low-e coatings with a first surface coating of a magnetron sputtered vapor deposition coating consisting primarily of titanium dioxide. The titanium dioxide achieves a hydrophilic photocatalytic surface to produce a solar collector which is self-cleaning for increased solar energy transmittance with less cleaning cost.

1 . A solar collector comprising:
 a box having a means for collecting and removing useful solar energy from the box, and an opening in the box arranged to receive solar radiation; and   a glass pane without a low-E coating with a pre-installation solar energy transmittance of greater than 85% and having an outer surface coated with a photoactive, photocatalytic titanium dioxide coating of less than 100 angstroms in thickness applied by Magnetron Sputter Vapor Deposition, the titanium dioxide coating of the type which when exposed to ultraviolet light activates the outer surface to a hydrophilicity to the extent of having a water droplet contact angle of 0-25°, and to be photocatalytic to degrade organic matter in contact with the outer surface, the glass pane covering the opening in the box.   
     
     
         2 . The solar collector of  claim 1  wherein the means for removing solar energy from the box comprises collecting tubes containing a fluid. 
     
     
         3 . The solar collector of  claim 1  wherein the means for removing solar energy from the box comprises an array of solar cells. 
     
     
         4 . The solar collector of  claim 1  wherein the titanium dioxide coating is such that when activated by ultraviolet light the surface achieves a water droplet contact angle of less than 20°. 
     
     
         5 . The solar collector of  claim 1  wherein the glass pane solar energy transmittance is greater than 88%. 
     
     
         6 . The solar collector of  claim 1  wherein the glass pane solar energy transmittance is greater than 89%. 
     
     
         7 . The solar collector of  claim 1  wherein the glass pane transmittance of visible light is greater than 89%. 
     
     
         8 . The solar collector of  claim 1  wherein the glass pane is translucent tempered glass. 
     
     
         9 . The solar collector of  claim 1  wherein the glass pane is constructed of low iron glass of less than 0.1% iron oxide computed on Fe 2 0 3 . 
     
     
         10 . A photovoltaic or thermal solar collector comprising:
 an enclosure;   a solar cell or a thermal collecting tube arrangement within the enclosure; and   a protective glass cover pane overlying the enclosure, the cover pane having a Magnetron Sputter Vapor Deposition coating with a primary element of TiO 2  less than 100 angstroms in thickness which is photocatalytic and super hydrophilic, the cover pane having a transmittance of greater than 85 percent.