Finned tube solar energy absorber

DETAILED DESCRIPTION It is among the objects of the present invention to provide an efficient, low cost, easily manufactured flat plate type solar collector which utilizes tubing but does not require any type of flat plate surface of any flat plate type of absorber surface to be mounted, soldered or welded to the tubular surface.
My improved solar energy absorber comprises a plurality of generally parallel lengths of finned tubing.
Preferably, the tubing is high fin aluminum clad copper tubing such as Type L/C tubing manufactured by Wolverine Division of UOP Inc.
The height of the fins should be as great as possible, while the internal diameter of the tubing should not exceed 0.
375-0.
500 inches.
An outer fin diameter of at least one inch and preferably close to 2 inches is desirable in order to maximize the fin area exposed to the sun while minimizing the amount of tubing required.
The tubing can be bent in serpentine fashion after portions of its fins are removed, or are not provided in the first place, so that all of the heat transfer fluid passes through all of the tubing.
Alternatively, a plurality of parallel lengths of finned tubing can be mounted between inlet and outlet headers so that the flow will be divided.
The serpentine configuration can also incorporate U-shaped fittings at each end to reverse the flow.
The fins on adjacent parallel sections of tubing are preferably positioned very close together, about 0.
010-0.
050 inches so as to capture as much radiation as possible.
The tubing sections are also preferably positioned in a generally vertical direction with their axes at an angle between 20.
degree.
and 60.
degree.
to the ground, depending on the latitude, so that the sun will impinge on the flat side surfaces of the fins.
The tubular energy absorber is preferably positioned in formed channels in an unskinned urethane foam insulator block located in the bottom of a solar collector housing which may have extruded aluminum sides, for example.
This foam is used because of its lower thermal conductivity and because it can be used as a structural support for the fin-tube energy absorber