Solar furnace

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Drawing sheet — no readable text.

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Drawing sheet — no readable text.

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mounted in front of the corrugated portion and secured

SOLAR FURNACE to the tank, while insulation 16 surrounds the tank and

CROSS REFERENCE TO RELATED

an insulated cover (FIG. 1) completes the insulation.

APPLICATION

Water is circulated through the tank through the tubing 22. The cold water enters at the upper end 24 as

This application is a division of my application Ser. the tube passes through the end wall 12 and is bent to No. 136,896, filed Apr. 3, 1980, now U.S. Pat. No. form lengths 26 (4 shown) with the heated water pass 4,326,501. ing out at the end 28. The ends 26 and 28 are directly BACKGROUND OF THE INVENTION connected with the building's water system since the 10 unit operates on the normal water supply pressure.

Solar units are now becoming popular for heating The tank 40 is now filled with a suitable heat storage water and buildings. However, these are costly to man material. The preferred material is eutectic salts. These ufacture and to install. Most of these units are mounted salts store the heat from the collector side of the tank. on the roof and act as solar collectors. The heat col They also act as heat transfer mediums to heat the water lected must then be stored and some means of heat 15 passing through the tubes 22. The salts are added after exchange must be provided. The system must be pro the tank is placed in its permanent site by heating to the vided with differential thernostats, controls, pressure melting point (80) and pouring into the tank and reducing controls and other types of controls, all com around the tubes 22. Other materials, such as concrete, plex and costly. may also be used for the purpose.

SUMMARY OF THE INVENTION In operation, the solar rays strike the tank 10 particu larly

The present invention greatly reduces the complexity material at the corrugations 20, to transfer the heat to the and cost by providing a single unit which serves as the in contactin with the tank. The material, salts, concrete, etc., is solar collector heat storage area, and the heat ex 25 The water is thusthe tubing 22 which carries the water. changer. A steel or reinforced fiberglass tank is pro tic salts or other materialas serves heated it passes through. The eutec to store the heat and vided with one wall which is oriented at an angle that transfers it to the water. The unit is thus a self-con allows maximum insolation during December and Janu tained, free standing solar heat collector, solar heat ary north of the equator. This is approximately equal to storage, and solar heat exchanger in a single compact the latitude of installation plus 10'. Tubing is used to carry the cold water from the building supply through 30 unit. This eliminates the need for differential thermo stats, controls, heat exchangers, and pressure reducing the tank and back to the building hot water system of controls. It can be installed in old and new structures for heater. The tank is filled and surrounds the tubing with eutectic salts or similar material or concrete for storing home or industrial hot water systems with two simple the heat from the collector side of the tank. These salts pipe connections. The unit thus uses the heat storage also act as heat transfer agents to heat the water passing 35 area itself as the solar collector and heat exchanger. The through the tubing. The salts are added to the tank after cost is comparatively small.

the tank has been placed in its permanent site by heating The unit is modular in that one or more additional the salts to their melting point (80) and pouring into the units can be readily hooked up in series or parallel with tank. The unit is modular and several units can be at a minimum of plumbing. By doubling the tubing in the tached in series or parallel if desired. unit, it can be used for a low pressure hot water heating system using a single unit.

DESCRIPTION OF THE DRAWINGS The invention readily lends itself to variations. For In the drawings: example, FIG. 4 illustrates a method of cutting further FIG. 1 is a perspective view of the cover for the unit costs and reducing the size. The solar furnace 30 is a flat of the present invention; 45 rectangular housing and is mounted on a cradle 32 at an FIG. 2 is a perspective view, partly broken away, of angle of 45-52 facing the sun.

the solar furnace of the present invention; As in the previous embodiment, the furnace com FIG. 3 is a side elevation of the tubing designed to prises a tank with thick insulation thereabout. The tank carry the water through the unit; has one metallic wall 34 exposed to solar radiation. The FIG. 4 is a perspective view of a modified form of the 50 flat metallic plate 34 is covered by the insulating glass or invention; plastic twin-wall (not shown). The interior is made as in FIG. 5 is a perspective view of a second modified the main form, with the water carrying tubing sui form of the invention; and rounded by eutectic salts or other material. FIG. 6 is a perspective view of a modified form of the For ease of handling, the form shown in FIGS. 5 and invention similar to the form shown in FIG. 5. 55 6 may be used. However, the small size requires a plu DESCRIPTION OF THE INVENTION rality of such units to be set up in a bank to equal the capacity of the main form. Referring to FIG. 5, a rack

Referring more in detail to the drawings, FIGS. 1,2 36 is designed to hold a plurality of units at an angle and 3 illustrate a solar furnace designed to be placed facing the sun, the latitude plus 10 for optimum results. outside of a structure on the ground and connected to The rack is provided with insulation within its interior the building's water system to provide hot water. so that all but the exposed face 38 is insulated. As in the The solar furnace comprises a steel or reinforced previous embodiment of FIG. 2, the exposed face is glass fiber tank 10 having insulated end walls 12, a top preferably covered by a twin-glass insulating plate, (not wall 14 and a front wall 16. The front wall 16 and the shown). The tank comprises an elongated rectangular top 14 are cut out at 18 as shown in FIG. 2. The front 65 metallic housing provided with an intermediate opening is covered with a corrugated wall 20, the angle of corru 40 through which the storage material such as the eu gation being equal to the latitude plus 10'. Insulating tectic salts can be poured and the hole sealed. The water glass or transparent plastic twin-wall (not shown) is passes through a straight tube passing through the tank

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and storage material. The elongated form provides suf invention will be readily apparent to a person skilled in ficient contact for heating. The pipes 42 are connected the art.

I claim:

in series to ensure sufficient heat from a plurality of 1. A solar furnace comprising a watertight tank capa units. These units are cheap to build and easy to handle. e of storing phase change material that changes from FIG. 6 illustrates a variation of the unit shown in solid to semi-solid to liquid form, thickly insulated walls FIG. 5. Here the metallic tank 44 is similar to the tank all but one wall of said tank, said one wall being a metal of FIG. 5 except that it is round. The rest of the con lic wall that is exposed to permit solar radiation to be struction and mounting is the same as in FIG. 5, accord 10 absorbed material, therethrough directly to said phase change said tank having a conduit through one of its ingly a plurality of cylindrical units of FIG. 6 may be outer walls and into and through said phase change inserted into the insulated rack 36. The units shown in material for passing a liquid into and out of said tank, FIGS. 5 and 6 can be easily stacked side by side and said tank being mounted on a support outside the builde connected to the water supply with a minimum of ing for holding the tank at an angle to the horizontal so plumbing because of the ease of handling and simplicity, 15 that the plate will be at an angle substantially equal to these units are fairly inexpensive to manufacture and set the2.latitude of installation plus ten degrees. A solar furnace as in claim 1 wherein said support

I have thus provided a simple and inexpensive solar is a3.cradle that holds the tank at an angle facing the sun. A solar furnace as in claim 2 wherein said support's furnace which combines in a single unit a solar collec an insulated cradle into which a plurality of tanks may tor, solar storage, and a heat exchanger. The unit is be received.

cheap and efficient. Other advantages of the present