Tubular heating-pipe solar water-heating-system with integral tank

Abstract

A collector core for a solar water-heating-system includes a plurality of heat-absorbing pipes each of which surrounds a cooler-water return-pipe. The heating-pipes may connect directly to an insulated hot-water storage-tank from which cooler water descends through the return-pipes into the heating-pipes. Upon reaching the end of the return-pipes, the cooler water flows outward into the space between the surrounding heating-pipes and the inner return-pipes. Upon warming, water between the two pipes rises upward back to the hot-water storage-tank thus completing the thermosyphon flow cycle. Preferably, the inner return-pipe is made of polyvinyl chloride (“PVC”), polybutelene (“PB”), or other compressible material which permits collector core operation both in freezing and non-freezing environments. Alternatively, the collector core may be added to an existing solar water-heating panel to improve its operation.

1. A solar water-heating collector core adapted for incorporation into a solar water-heating-system either by being joined to a lower portion of a hot-water storage-tank, or by being joined to a lower portion of another solar water-heating-panel, the solar water-heating collector core comprising:
 (a) a plurality of hollow heating-pipes, each heating-pipe having a longitudinal axis and an interior that is surrounded by an outer wall; said heating-pipes, when assembled to form the collector core, being arranged so the longitudinal axes are disposed substantially parallel to each other; said heating-pipes being adapted to be inclined to the horizontal when in use with an upper end of each heating-pipe being elevated above a lower end of each heating-pipe; the lower end of each heating-pipe being closed, and the upper end of each heating-pipe being open and adapted to extend directly to, open into, and communicate directly with a lower level of the hot-water storage-tank or with the lower portion of the solar water-heating-panel; and  
 (b) a plurality of hollow cooler-water return-pipes, each of which is surrounded by the outer wall of one of the heating-pipes; the cooler-water return-pipe within each heating-pipe having an internal cross-sectional area that is approximately equal to one-third (⅓) to one-half (½) of an internal cross-sectional area of the outer wall of the heating-pipe, and having a length that is slightly longer than a length of the outer wall of the heating-pipe so the open upper end of the cooler-water return-pipe extends beyond the open upper end of the outer wall thereby permitting the upper end of the cooler-water return-pipe to extend into and communicate directly with the lower level of the hot-water storage-tank or with the lower portion of the solar water-heating-panel; and the lower end of each cooler-water return-pipe being perforated so fluid may flow outward from within the lower end of each cooler-water return-pipe toward the surrounding outer wall of said heating-pipe;  
 
     wherein lower ends of the heating-pipes whether fitted with or without a drain valve are free to move longitudinally to accommodate thermal expansion and contraction. 
   
   
     2. The solar water-heating collector core of  claim 1  wherein middle portions of the heating-pipes are loosely secured by low friction sleeve collars to the solar water-heating-panel casing or frame and lower ends of the heating-pipes are loosely secured or seated on a spring or flexible corrugated polymer hose seat in a cup or sleeve collar fixed onto the solar water-heating-panel casing or frame. 
   
   
     3. The solar water-heating collector core of  claim 2  wherein said heating-pipes are thermally joined to a heat-conducting sheet, wherein an upper face of said heat-conducting sheet and of said heating-pipes are provided with a heat-absorbing surface, and wherein a lower face of said heat-conducting sheet is provided with a heat-reflective surface. 
   
   
     4. The solar water-heating collector core according to  claim 3  wherein said heating-pipes are disposed slightly above a sheet having heat-reflective upper face and lower face, and wherein said heating-pipes are provided with a heat-absorbing surface. 
   
   
     5. The solar water-heating collector core according to  claim 4  wherein said collector core further comprises a casing having a transparent cover disposed over the heating-pipes, and thermal insulation disposed beneath the heating-pipes. 
   
   
     6. The solar water-heating collector core of according to  claim 5  wherein the heating-pipes are adapted to screw into sockets that are joined either to the lower portion of the hot-water storage-tank, or to the lower portion of another solar water-heating-panel. 
   
   
     7. The solar water-heating collector core according to  claim 6  wherein the heating-pipes are joined to the bottom manifold of the solar water-heating-panel. 
   
   
     8. The solar water-heating collector core according to  claim 7  wherein said collector core further comprises the hot-water storage-tank. 
   
   
     9. The solar water-heating collector core according to  claim 8  wherein said cooler-water return-pipes are made of a compressible material for absorbing freezing pressure of ice formation during cold periods without damage to the collector core.