Non-tracking solar collectors

Abstract

The invention concerns a non-tracking solar collector which includes laterally spaced, radiation-transmitting prisms ( 26 ) which are wedge-shaped in cross-section. Each prism ( 26 ) has major side surfaces ( 28, 30 ) converging at an acute angle ( 32 ) to a relatively narrow end ( 34 ) of the prism ( 26 ), and an opposite, relatively wide end ( 36 ). For each prism ( 26 ) there is a refractor ( 22 ), typically a linear refractor such as a linear Fresnel lens, arranged over the prism ( 26 ) to refract solar radiation incident thereon onto the major side surfaces ( 28, 30 ) of the prism ( 26 ), as the sun moves relative to the earth, at angles allowing such radiation to enter the prism ( 26 ) and be internally reflected towards a target ( 38 ) at the relatively wide ( 36 ) end of the prism ( 26 ). The refractors ( 22 ) are spaced laterally apart from one another, possibly by intermediate, radiation transmitting panels ( 24 ) which are continuous with the refractors ( 22 ). In the preferred construction, the refractors ( 22 ) and intermediate panels ( 24 ) form an integral part of a roof or wall cladding structure.

1 . A non-tracking solar collector comprising:
 a plurality of laterally spaced, radiation-transmitting prisms which are wedge-shaped in cross-section and which have major side surfaces converging at an acute angle to a relatively narrow end of the prism, each prism having an opposite relatively wide end; and   for each prism, a refractor arranged over the prism to refract solar radiation incident thereon onto the major side surfaces of the prism, as the sun moves relative to the earth, at angles allowing such radiation to enter the prism and be internally reflected therein towards a target at or adjacent the relatively wide end of the prism, the refractors being spaced laterally apart from one another.   
     
     
         2 . A non-tracking solar collector according to  claim 1  wherein the refractor is a linear refractor. 
     
     
         3 . A non-tracking solar collector according to  claim 2  wherein the refractor is a linear Fresnel lens. 
     
     
         4 . A non-tracking solar collector according to  claim 1  wherein the refractors are spaced apart from one another by radiation-transmitting panels which are continuous with the refractors. 
     
     
         5 . A non-tracking solar collector according to  claim 4  wherein the collector is configured to form part of a roof or wall cladding structure. 
     
     
         6 . A non-tracking solar collector according to  claim 5  wherein the linear refractors and radiation-transmitting panels form a corrugated expanse of roof or wall cladding. 
     
     
         7 . A non-tracking solar collector according to  claim 6  wherein the linear refractors are arranged at the crests of the corrugations and the radiation-transmitting panels at the valleys thereof. 
     
     
         8 . A non-tracking solar collector according to  claim 6  wherein the narrow edges of the prisms extend in the pitch direction of an expanse of pitched roof cladding. 
     
     
         9 . A non-tracking solar collector according to  claim 8  wherein the narrow ends of the prisms extend E-W in a pitched roof cladding structure the ridge cap of which extends N-S. 
     
     
         10 . A non-tracking solar collector according to  claim 4  wherein the linear refractors and radiation-transmitting panels form a flat expanse of roof or wall cladding. 
     
     
         11 . A non-tracking solar collector according to  claim 4  wherein the narrow ends of the prism's are adjacent to or in contact with the linear refractors. 
     
     
         12 . A non-tracking solar collector according to  claim 11  comprising reflector structures between the prisms. 
     
     
         13 . A non-tracking solar collector according to  claim 12  wherein each reflector structure includes a pair of convergent reflector panels arranged to reflect radiation which is transmitted by the radiation-transmitting panels onto the prisms for collection and concentration by the prisms. 
     
     
         14 . A non-tracking solar collector according to  claim 1  comprising a radiation transmitting secondary solar concentrator at the wider end of each prism. 
     
     
         15 . A non-tracking solar collector according to  claim 14  wherein the secondary solar concentrator has side walls which converge towards one another to a width less than that of the wider end of the prism. 
     
     
         16 . A non-tracking solar collector according to  claim 15  wherein the side walls of the secondary solar concentrator are planar or concave. 
     
     
         17 . A non-tracking solar collector according to  claim 14  wherein the secondary solar concentrator is made of a material with a higher refractive index than the material of which the prism is made. 
     
     
         18 . A non-tracking solar collector according to  claim 14  wherein the prism and secondary solar concentrator meet one another at a curved interface. 
     
     
         19 . A non-tracking solar collector according to  claim 18  wherein a convex surface of the secondary solar concentrator mates with a concave surface of the prism at the interface. 
     
     
         20 . A solar collector according to  claim 1  comprising a PV cell at the wider end of each prism. 
     
     
         21 . A solar collector according to  claim 14  comprising a PV cell at an end of the secondary solar collector remote from the prism. 
     
     
         22 . A solar collector according to  claim 1  comprising a pipe conveying a fluid which is to be heated at the wider end of the prism. 
     
     
         23 . A non-tracking solar collector according to  claim 14  comprising a pipe conveying a fluid which is to be heated at an end of the secondary solar concentrator remote from the prism.