Solar collector for fluid heating system

#The rapidly increasing use of solar energy in homes and elsewhere has given rise to an immediate need for a more efficient, economical and practical solar collector. The objective of this invention is to satisfy this need to the maximum possible extent by providing a solar collector of improved operational efficiency and mechanical construction.

#A principal feature of the present invention is the utilization in a solar collector of a pair of collector coils for fluid to be heated in which the flow of fluid in each coil is independently controlled by temperature-responsive valves, one for each coil, the valves remaining closed to block fluid flow in their coils below a certain fluid temperature, and then opening gradually toward a full open flow condition as the fluid temperature in the associated coil increases.

#Another feature of the invention is the arrangement of two serpentine collector coils in spaced parallel planes within a common collector housing and in laterally offset parallel relationship to such an extent that the serpentine loops of the two coils overlap laterally by approximately one-half of the width of each loop. This offset relationship enables the two coils of the collector to utilize the sun's ray energy to the maximum possible extent, resulting in increased thermal efficiency for the collector.

#FIG. 1 is a partly schematic perspective view of a fluid heating system utilizing solar collector units embodying the present invention.

#FIG. 2 is a side elevational view, partly in cross section, showing a solar collector unit.

#FIG. 3 is a horizontal section taken on line 3--3 of FIG. 2.

#Referring to the drawings in detail wherein like numerals designate like parts, a solar collector 10 forming the principal subject matter of the invention comprises a shallow rectangular housing or pan 11 preferably formed of aluminum and including a top outwardly directed continuous marginal flange 12, as best shown in FIG. 4. The side and bottom walls of the housing 11 are jacketed with thermal insulating material 13, such as urethane, this material being suitably bonded to the exterior surfaces of the housing 11. The insulating material 13 is enclosed within an outer preferably aluminum shell or skin 14, also bonded adhesively to the insulating material and providing a vapor barrier thereon. The elements 11, 12, 13 and 14 are of unit construction in the shallow housing or pan of the collector unit 10. The interior surfaces of the rectangular housing 11 are provided with a dull black finish to promote thermal efficiency.

#The open top of the housing 11 of collector 10 has a removable cover 15 consisting of a clear tempered glass panel 16 having a continuous marginal edge U-cross section elastic seal 17, FIG. 4. A right angular rectangular cover frame 18 rests on the marginal seal 17 and is clampingly secured to the marginal flange 12 by a series of conventional thumb locks 19 carried by the frame 15 in spaced relationship around the rectangular collector unit. This arrangement securely seals the interior of the collector housing 11 when the cover 15 is in place and allows ready access to the interior of the housing when maintenance is required. The described construction of the collector housing and its cover means is entirely practical and economical, sturdy and efficient compared to some rather haphazard arrangements which have been utilized heretofore in solar collectors.

#Within the housing 11 is a pair of independent elongated serpentine preferably copper collector coils 20 and 21. As shown in FIGS. 2 and 3, these two coils span the major portions of the length and width of the rectangular housing. The serpentine coils 20 and 21 are spaced apart in the housing in parallel planes above and parallel to the bottom wall of the housing 11. The two coils are firmly supported in fixed relationship within the housing by a suitable number of transverse apertured coil support webs 22 fixed within the housing 11, as shown in FIGS. 2 and 3.