Open-flow solar collector

Abstract

The invention relates to a field of open-flow solar collectors, and specifically to flat solar collectors with wetting the underneath sides of their solar radiation absorbing plates with liquid heat transfer medium. More specifically, the invention proposes the flat solar collector, which operates with relatively low flow rate of the heat transfer medium on the backside of the solar radiation absorbing plate, with flow in the form of some rivulets. The invention discloses some technical solutions, which restrict meandering rivulets' flow. These technical solutions are based on application of longitudinal strips attached by permanent magnets to the backside of the solar radiation absorbing plate fabricated from ferromagnetic metal.

1 . A flat open-flow solar collector consisting of following main units:
 a housing with an internal thermal insulation of its bottom and side walls; the internal surfaces of the layers of said internal thermal insulation are covered with impervious layers;   a solar radiation absorbing plate, which is fastened in said housing and joined with said housing; said solar radiation absorbing plate is fabricated from ferromagnetic metal; the upper side of said solar radiation absorbing plate is covered with solar radiation absorbing paint at least in visible range of electromagnetic radiation and the backside of said solar radiation absorbing plate is covered with corrosion resistive coating;   a distributing pipe; the proximal section of said distributing pipe is placed outside said housing, and its middle and distal sections are installed on the backside of said solar radiation absorbing plate; said distributing pipe is provided with openings, which supply evenly water or other liquid mediums on the upper section of said backside of said solar radiation absorbing plate; the upper section of said backside of said solar radiation absorbing plate is provided with some pipe clips serving for fastening said distributing pipe;   rivulets' flow restricting longitudinal means, which divide the backside of said solar radiation absorbing plate into a set of longitudinal parallel zones; said rivulets' flow restricting longitudinal means entrap the rivulets when they meet said rivulets' flow restricting longitudinal means with transforming the shapes of transverse cross-sections of said rivulets and following flow of said transformed-shape rivulets along said rivulets' flow restricting longitudinal means; said rivulets' flow restricting longitudinal means are designed as parallel metal strips with ferromagnetic properties like said ferromagnetic metal of the solar radiation absorbing plate; said metal strips are covered on their both sides and their edges with a corrosive resisting paint and they are placed apart longitudinally with a certain mutual interval on the backside of said solar radiation absorbing plate; each said metal strip is fastened on the backside of said solar radiation absorbing plate by some permanent magnets;   an outlet connection, which is situated in lower section of said housing of said open-flow solar collector and serves for withdrawing the water or other liquid mediums from the internal space between said solar radiation absorbing plate and said impervious layers of said internal thermal insulation;   a venting opening, which provides fluid communication of said space between said solar radiation absorbing plate and said impervious layers with the surrounding atmosphere.   
     
     
         2 . A flat open-flow solar collector as claimed in  claim 1 , wherein said flat open-flow solar collector serves for evaporation and concentration of aqueous solutions; said flat open-flow solar collector is provided with inlet and outlet connections for supply of the air into the space between the solar radiation absorbing plate and the impervious layers of the thermal insulation and removal of the air from said space. 
     
     
         3 . A flat open-flow solar collector as claimed in  claim 1 , wherein the housing is provided with glazing covering the aperture of said housing. 
     
     
         4 . A flat open-flow solar collector as claimed in  claim 1 , wherein each metal strip is provided with at least one longitudinal bead with forming a wedge-wise gap between said bead and the adjacent surface of the backside of the solar radiation absorbing plate. 
     
     
         5 . A flat open-flow solar collector as claimed in  claim 4 , wherein the strips are fabricated from anticorrosive material and provided with some openings; there are O-rings, which are placed concentrically with said openings; the diameter of each said opening lies in the interval between the inner diameter of said O-rings and their outer diameter; tapered conical permanent magnets, which have their top diameter somewhat smaller that the inner diameter of said O-rings and the base diameter of said tapered conical permanent magnets is somewhat larger than the inner diameter of said O-rings, are inserted with their tapered sections into said openings and said O-rings until their immediate contact with the backside of the solar radiation absorbing plate; said top and base diameters of said O-rings are chosen in such a way, that insertion of said tapered conical permanent magnets causes radial extending of said O-rings and friction forces between said tapered conical permanent magnets and said O-rings held in place said strips in contact with the backside of the solar radiation absorbing plate. 
     
     
         6 . A flat open-flow solar collector as claimed in  claim 4 , wherein the strips are fabricated from anticorrosive material and provided with some openings; each said opening is provided with a vertical flanging, and there is the O-ring, which is inserted into said opening; the tapered conical permanent magnet keeps close said O-ring against said opening flanging; said tapered conical permanent magnet is inserted into said opening flanging until its immediate contact with the backside of the absorbing plate with attendant deformation of said O-ring. 
     
     
         7 . A flat open-flow solar collector as claimed in  claim 4 , wherein the longitudinal strips provided with two longitudinal beads each one and two lateral strips provided with one longitudinal bead each one are joined with forming a grate with a frame comprising said two lateral strips; the upper and lower sections of said longitudinal strips' beads and said beads of said lateral strips are joined together by upper and lower webs. 
     
     
         8 . A flat open-flow solar collector as claimed in  claim 7 , wherein the longitudinal strips and the lateral longitudinal strips of the grate are provided with openings. 
     
     
         9 . A flat open-flow solar collector as claimed in  claim 7 , wherein the longitudinal strips and the lateral longitudinal strips of the grate are provided with flanged openings. 
     
     
         10 . A flat open-flow solar collector as claimed in  claim 1 , wherein the distributing pipe is provided with nozzles, which are terminated with flexible sleeves; pipe clips are installed on the backside of the solar radiation absorbing plate and serve for securing said distributing pipe. 
     
     
         11 . A flat open-flow solar collector as claimed in  claim 10 , wherein the distal ends of the flexible sleeves are sealed and the longitudinal sections of their walls facing to the backside of the solar radiation absorbing plate are provided with some openings.