Solar heat collector for heating a circulating fluid and process for manufacturing a solar heat collector

Abstract

A solar heat collector is presented for heating a circulating fluid with an inner glass tube and an outer glass tube. The glass tubes are connected at their open ends, and the space between the inner tube and the outer tube being evacuated, wherein the inner space of the inner tube is divided by an insert to define a first channel and a second channel. Said channels are connected at the closed end of the inner tube. The inner glass tube and the outer glass tube have smooth inner and outer surfaces, and the insert is provided such that the first and second channels and a space between the end of the insert and the closed end of the inner tube define the same cross-section.

1 . A solar heat collector for heating a circulating fluid with an inner glass tube having an open end and a closed end, and an outer glass tube having an open end and a closed end, wherein the inner glass tube and the outer glass tube are connected at the open ends of both glass tubes, and a space between the inner glass tube and the outer glass tube is evacuated, wherein the inner space of the inner glass tube is divided by an insert to define a first channel and a second channel within the inner glass tube, the first and second channels being connected at the closed end of the inner glass tube, wherein the inner glass tube and the outer glass tube have smooth inner and outer surfaces, and the insert is provided such that the first and second channels and a space between the end of the insert and the closed end of the inner glass tube define the same cross-section. 
     
     
         2 . The solar heat collector of  claim 1 , wherein the insert is a thin plate of glass dividing the inner space of the inner glass tube, such that the first and second channels are identical. 
     
     
         3 . The solar heat collector of  claim 1 , wherein the insert is extruded in one-piece with the inner glass tube. 
     
     
         4 . The solar heat collector of  claim 1 , wherein the insert is a sheet metal dividing the inner space of the inner glass tube, such that the first and second channels are identical. 
     
     
         5 . The solar heat collector of  claim 2 , wherein the insert has on both length sides curved wings having the same curvature as the curvature of the inner glass tube. 
     
     
         6 . The solar heat collector of  claim 5 , wherein the wings are press-fit arranged towards the inner surface of the inner glass tube. 
     
     
         7 . The solar heat collector of  claim 2 , wherein at least one surface of the insert is provided with longitudinal ribs. 
     
     
         8 . The solar heat collector of  claim 7 , wherein the ribs have a triangular shape. 
     
     
         9 . The solar heat collector of  claim 7 , wherein the ribs have a corrugated shape. 
     
     
         10 . The solar heat collector of  claim 1 , wherein the insert has a cross shaped inner part that divides the inner space of the evacuated glass tube into two first channels and two second channels. 
     
     
         11 . The solar heat collector of  claim 10 , wherein the cross shaped inner part comprises an elongated first flat sheet metal part and two identical second flat sheet metal parts that are mounted at right angles along the center lines on both sides of the first sheet metal part, and wherein the widths of the first flat sheet metal part and the two second flat sheet metal parts are commensurate to the inner diameter of the evacuated glass tube. 
     
     
         12 . The solar heat collector of  claim 1 , wherein the insert has a flat central part and bulging edges with rounded rims whereby the insert is pinched towards the inner glass tube of the evacuated glass tube. 
     
     
         13 . A process for manufacturing the solar heat collector of  claim 1 , wherein an inner glass tube having an open end and a closed end, and an outer glass tube having an open end and a closed end are produced and connected at the open ends of the inner glass tube and the outer glass tube, such that a space is left between the inner glass tube and the outer glass tube, wherein said space is evacuated by means of an evacuation pump, further providing an insert into the inner glass tube which divides the inner glass tube into a first channel and a second channel such that the first and second channels and a space between the end of the insert and the closed end of the inner glass tube define the same cross-section. 
     
     
         14 . The process according to  claim 13 , wherein the insert is made of glass and is extruded in one piece with the production of the inner glass tube.