Abstract: A solar heat collector assembly includes a cylindrical transparent tube having an open end portion hermetically sealed by the use of a sealant and being held in vacuum state and a heat-collecting pipe secured in the transparent tube with its end portion extending outside the transparent tube through the sealant. The sealant of a transparent material, for example, is bowl-shaped and the heat-collecting pipe is secured to pass through the center of the bowl-shaped sealant. The pipe and the sealant are bonded together through the use of a proper adhesive metal material. The outer periphery of the sealant is further bonded to the open end portion of the transparent tube. The adhesive metal material is typically 426 alloy.

Abstract: An evacuated, one-wall tubular housing having a reflector positioned at the opposite side of the tubular housing from the radiation energy of the sun. The tubular housing includes a solar energy absorber member of a cylindrical shape, for example, and a metal tube provided for maintaining an energy absorbing media such as water in good heat transfer relationship with the absorber member. The system can improve the efficiency of the total energy collection without the need to track movement of the sun or focus the reflected radiation upon a particular point. The reflector has a curved reflecting surface corresponding to a segment of a cycloid or trochoid curve. In the case of an array of the tubular housings, the cycloid or trochoid curve of the reflecting surface is defined as a function of the tubular housing diameter and the distance between the adjacent housings.

Abstract: A length of a tubing is helically wound with a fin made of a heat-radiating strip and which is corrugated to provide a series of transverse crimps. A base is provided by flattening a portion of the crimps with the use of pressure rollers at one edge of the strip when the section of the fin is "L" shaped, or at the middle of the strip when the section of the fin is "U" shaped in order to cling closely to the tubing. The fin is bent at the boundary area between the flattened portion and the crimped portion when the fin is helically wound around the tubing.