Solar uv transmissive device for sterilizing and/or heating air

Abstract

An outdoor air conduit or plenum is provided with a UV transmissive surface for allowing the air circulated through the conduit to be exposed to the UV rays of the natural sunlight, thereby providing for the sterilization of the air using free energy. The air sterilization system can be integrated to a building ventilation system or combined with a solar heat collector.

1 . A heat collector and air sterilization device comprising: a UV transmissive glazing exposed to the ambient, the UV transmissive glazing allowing at least a portion of the UV rays of the sunlight to pass therethrough, the UV transmissive glazing being spaced from a solar radiation absorbing panel and defining a plenum therewith, a plurality of perforations defined through the UV transmissive glazing for allowing outside air to flow through the UV transmissive glazing into the plenum, the perforations being distributed over a surface area of the UV transmissive glazing, the plenum having at least one outlet through which air contained in the plenum can be removed after having been warmed up and at least partly sterilized by the UV rays of the sunlight. 
     
     
         2 . The device defined in  claim 1 , wherein said solar radiation absorbing panel overlies a layer of insulation material of a building wall. 
     
     
         3 . The device defined in  claim 1 , wherein the solar radiation absorbing panel is corrugated. 
     
     
         4 . The device defined in  claim 1 , wherein the solar radiation absorbing panel has an elongated pipe-like configuration with the UV transmissive glazing running longitudinally along one side thereof. 
     
     
         5 . The device defined in  claim 1 , wherein the ratio of the perforated surface of the UV transmissive glazing over the imperforated surface of the glazing ranges from 0.5% to 10%. 
     
     
         6 . The device defined in  claim 1 , wherein the UV transmissive glazing is permeable to UV rays of the C-type, and has a UV transmittance rate that is higher than 80%. 
     
     
         7 . The device defined in  claim 6 , wherein the UV transmissive glazing is made of a material selected from the group consisting of: poly carbonates and fused silicate. 
     
     
         8 . The device defined in  claim 7 , wherein the UV transmissive glazing is made of a polycarbonate having a UV transmittance equal to or greater than 90% at wavelength comprised between between 180 nm-2.0 μm. 
     
     
         9 . A device for heating and sterilizing air comprising an outdoor perforated UV transmissive surface allowing at least part of the solar radiations, including UV rays, to pass therethrough, a solar radiation absorption surface located behind said outdoor perforated UV transmissive surface for absorbing the solar radiations, and a plenum defined between said outdoor perforated UV transmissive surface and said radiation absorption surface, the air flowing in the plenum absorbing heat from the radiation absorption surface while being exposed to UV rays, thereby providing for the combined heating and sterilization of the air in the plenum by solar energy. 
     
     
         10 . The device defined in  claim 9 , wherein air moving means are provided for maintaining said plenum under negative pressure. 
     
     
         11 . The device defined in  claim 9 , wherein the outdoor perforated UV transmissive surface is mounted to a building surface, the plenum being defined between the perforated UV transmissive surface and the building surface. 
     
     
         12 . The device defined in  claim 11 , wherein the building surface is a transparent membrane extending over a greenhouse skeleton structure. 
     
     
         13 . The device defined in  claim 11 , wherein the building surface forms part of the solar radiation absorption surface and is of a light color. 
     
     
         14 . The device defined in  claim 9 , wherein the solar radiation absorption surface comprises a collector panel mounted to a building surface, the outdoor perforated UV transmissive surface separating the collector panel from the ambient. 
     
     
         15 . A system for heating and sterilizing the air of a building comprising:
 at least one heat collector and air sterilization device as defined in  claim 1 ;   at least one inlet receiving air to be treated from inside the building; and   at least one outlet feeding the building with heated and sterilized air.   
     
     
         16 . A system as defined in  claim 15  further comprising: an auxiliary sterilization device selected from the group consisting of: a UV ray producing device, a chemical sterilization device and a photocatalyst device. 
     
     
         17 . A system as defined in  claim 16 , further comprising a controller for selectively actuating the auxiliary sterilization device. 
     
     
         18 . A system as defined in  claim 16 , wherein the auxiliary sterilization device is positioned downstream of said at least one heat collector and air sterilization device and upstream of the building relative to the flow of air through the system. 
     
     
         19 . A system as defined in  claim 15  comprising at least two heat collector and air sterilization devices mounted in parallel or in series. 
     
     
         20 . A system as defined in  claim 17 , wherein the controller actuates the auxiliary sterilization device when the intensity of the solar exposition is lower than about 300 W/m 2  and deactivates back the auxiliary device when the intensity of the solar exposition is higher or equal to 600 W/m 2 .