Solar Collector With Integrated Heat Storage

Abstract

The present invention relates to a solar collector having an integrated heat storage. Such a solar collector comprises a housing which comprises a bottom plate and a transparent cap, wherein between an involute mirror and the transparent cap a storage tank for the storage of water is provided. The solar collector according to the invention is characterized in that a shielding is provided between the transparent cap and the storage tank, which leaves the part of the storage tank that is situated lower uncovered. By using the solar collector according to the invention a higher thermal yield can be achieved while using less materials.

1 . Solar collector having an integrated heat storage, said solar collector comprising a housing which comprises a bottom plate and a transparent cap, where in the housing between an involute mirror and the transparent cap a storage tank for storage of water is disposed, the solar collector being arranged to be at an angle with the horizontal such that the storage tank has a higher end and a lower end, and wherein between the storage tank and the transparent cap a shielding is provided for reducing heat losses, said shielding being arranged at the higher end, between the storage tank and the transparent cap, and the shielding covering at least part of the higher end of the storage tank such that at the higher end convection between the storage tank and the transparent cap is inhibited characterized in that the shielding leaves at least part of the lower end uncovered whereby 20 to 60% of the volume of the storage tank is covered by the shielding, and an imaginary plane through the central axis of the storage tank, which plane is parallel with respect to the plane of the involute mirror, divides the shielding into a first part situated near the transparent cap and a second part near the involute mirror, wherein the volume of the storage tank encompassed by said first part is at least 15% larger than that of said second part. 
     
     
         2 . Solar collector according to  claim 1 , wherein at least part of the surface of the shielding is optically transparent. 
     
     
         3 . Solar collector according to  claim 2 , wherein part of the shielding is optically opaque, such that 2 to 5% of the most highly situated volume of the storage tank, is covered by the optically opaque part. 
     
     
         4 . Solar collector according to  claim 1 , characterized in that said first part covers at least 30% more volume than the second part. 
     
     
         5 . Solar collector according to  claim 1 , characterized in that the shielding has a lower edge that has an angle of 20° at most with respect to horizontal. 
     
     
         6 . Solar collector according to  claim 5 , characterized in that the lower edge is at an angle of 10° with respect to horizontal. 
     
     
         7 . Solar collector according to  claim 1 , characterized in that the shielding is fashioned out of polycarbonate. 
     
     
         8 . Method for placing a solar collector comprising:
 providing a solar collector having a housing which comprises a bottom plate and a transparent cap;   disposing a storage tank for storage of water in the housing between an involute mirror and the transparent cap;   arranging the solar collector to be at an angle with horizontal such that the storage tank has a higher end and a lower end,   providing a shielding for reducing heat losses between the storage tank and the transparent cap, said shielding being arranged at the higher end such that a lower edge of the shielding is at an angle with horizontal of ±30° at the most, the shielding covering at least part of the higher end of the storage tank such that at the higher end convection between the storage tank and the transparent cap is inhibited and such that the shielding leaves at least part of the lower end uncovered whereby 20 to 60% of the volume of the storage tank is covered by the shielding,   
       wherein an imaginary plane through the central axis of the storage tank, which plane is parallel with respect to the plane of the involute mirror, divides the shielding into a first part situated near the transparent cap and a second part near the involute mirror, wherein the volume of the storage tank encompassed by said first part is at least 15% larger than that of said second part. 
     
     
         9 . Method according to  claim 8 , wherein the lower edge of the shielding is at an angle with horizontal of ±20° at the most. 
     
     
         10 . Method according to  claim 8 , wherein the lower edge of the shielding is at an angle with horizontal not exceeding ±10°. 
     
     
         11 . Solar collector according to  claim 1 , characterized in that said first part covers at least 50% more volume than the second part.