Solar Collector Having An Integrated Heat Storage

Abstract

The present invention relates to a solar collector having an integrated heat storage (ICS), in which between an involute mirror and a transparent cover plate a storage tank for the storage of water is provided and in which the storage tank is provided with a light absorbing fin. At the lower end near the circumference of the storage tank the ICS according to the invention is provided with a fin system which comprises a light absorbing fin having a length in the longitudinal direction of the storage tank of at least 10 cm, and the fin system is designed such that the ICS lower end is shielded to a great extent, as a result of which losses by radiation and convection of air are restricted. Thus, the fin system has a double function.

1 . Solar collector having an integrated heat storage, in which said solar collector comprises a housing comprising a bottom plate and a transparent cover plate, where in the housing between an involute mirror and the transparent cover plate a storage tank for the storage of water is provided and the storage tank is provided with a light radiation absorbing fin, characterized in that the storage tank has a lower end and an upper end, the lower end near the circumference of the storage tank being provided with a fin system designed for the transfer of heat onto the storage tank, which fin system comprises a light absorbing fin having a longitudinal component in the longitudinal direction of the storage tank of at least 10 cm, and the fin system is designed such that, when the fin system is projected from a point (C) at the lower end of the storage tank situated on the center line through the storage tank on a virtual unit sphere situated outside the fin system having that point (C) as a center, the projected area as shielded by the fin system covers at least 25% of the area of the virtual unit sphere. 
     
     
         2 . Solar collector according to  claim 1 , in which the length of the light absorbing fin in the longitudinal direction of the storage tank is at least 15 cm. 
     
     
         3 . Solar collector according to  claim 1 , in which the fin system is designed tapered away from the storage tank. 
     
     
         4 . Solar collector according to  claim 3 , in which the fin of the fin system at the side of the transparent cover plate is at an angle with the center line that is more obtuse than that at the side of the involute mirror. 
     
     
         5 . Solar collector according to  claim 1 , in which the fin system comprises a pipe for heat transfer which connects the light absorbing fin with the storage tank. 
     
     
         6 . Solar collector according to  claim 5 , in which the pipe for heat transfer is a heat-pipe. 
     
     
         7 . Solar collector according to  claim 1 , in which at least 30% of the virtual area of a unit sphere having the point (C) as a center is covered by the fin system. 
     
     
         8 . Solar collector according to  claim 2 , in which the length of the light absorbing fin in the longitudinal direction of the storage tank is at least 20 cm. 
     
     
         9 . Solar collector according to  claim 7 , in which at least 35% of the virtual area of a unit sphere having the point (C) as a center is covered by the fin system.