Storage type solar water heater

Claim 2

A solar water heater comprising: a unitary housing structure providing a liquid-filled thermal storage compartment and a liquid-filled heating compartment, said housing structure providing a thermally insulating enclosure for said storage compartment, said thermally insulating enclosure including a base portion and a frontal wall portion extending upwardly therefrom, a heat transmitting window peripherally sealed to said housing structure, the window being spaced from an exterior surface of said frontal wall portion and defining therewith said heating compartment, and means defining a recirculation path for liquid extending downwardly through said storage compartment and upwardly through said heating compartment, said path defining means including: means defining a first liquid flow passage extending through said frontal wall portion between a lower end of the portion of said circulation path extending through said storage compartment and a lower end of the portion of said circulation path extending through said heating compartment, said first liquid flow passage providing first and second duct portions extending upwardly within the insulation of the frontal wall portion from said lower ends, and an intermediate duct portion interconnecting said first and second duct portions, means defining a second liquid flow passage extending through said frontal wall portion between an upper end of the portion of said circulation path extending through said heating compartment and an upper end of the portion of said circulation path extending through said storage compartment, said recirculation path constituting a thermosiphon responsive to absorption of solar radiation transmitted via said window into the heating compartment, and heating means in thermal contact with said intermediate duct portion of the first liquid flow passage for inhibiting reverse flow of liquid when the liquid in the heating compartment is cooler than the liquid in the storage compartment.

Claim 3

A solar water heater according to claim 1, wherein said heating means comprises a conductive heat exchanger extending between intermediate duct portion and the upper portion of the storage compartment.

Claim 4

A solar water heater according to claim 2, wherein said means defining the first liquid flow passage comprises a metallic tube, said intermediate duct portion being defined by a portion of said tube extending into the storage compartment, said tube portion constituting said conductive heat exchanger.

Claim 5

A solar water heater according to claim 1, wherein said exterior surface of the frontal wall portion is non-reflective and said window is of a material having a higher transparency to solar radiation than to infra red radiation reradiated from said surface.

Claim 6

A solar water heater according to claim 4, wherein the window is of glass.

Claim 7

A solar water heater according to claim 4, wherein the window is formed by two transparent panels spaced apart and defining an air space therebetween, each panel being peripherally sealed to the housing structure.

Claim 8

A solar water heater according to claim 1, wherein the window is formed by two panels, namely an interior and an exterior panel, spaced apart and defining an air space therebetween, said panels being peripherally sealed to the housing structure, the interior panel being thermally conductive and having a non-reflective exterior face, and the exterior panel having a higher transparency to solar radiation than to infra red radiation reradiated from said exterior face.

Claim 9

A solar water heater according to claim 1, including means to separate said portion of said recirculation path through said storage compartment from a further circulation path for liquid through said storage compartment, said further path extending between external water flow connections to said storage compartment.

Claim 10

A solar water heater according to claim 8, wherein said separating means comprises a tubular heat exchanger mounted in said storage compartment, and extending between said external water flow connections.

Claim 11

A solar water heater comprising: a unitary housing structure providing a horizontal base, said housing structure further providing a liquid-filled interior thermal storage compartment and a liquid-filled interior heating compartment, each said compartment having an upper portion and a lower portion, a thermally insulating enclosure for said storage compartment, said thermally insulating enclosure including a frontal wall portion sloping upwardly and rearwardly with respect to said base, a heat transmitting window peripherally sealed to said housing structure, the window being spaced forwardly from an exterior surface of said frontal wall portion and sloping upwardly and rearwardly with respect to the base, said heating compartment being confined between said exterior surface and said window, and means defining a recirculation path for liquid extending downwardly through said storage compartment and upwardly through said heating compartment, said path defining means including: means defining a first liquid flow passage extending through the frontal wall portion between a lower end of the portion of said circulation path extending through said storage compartment and a lower end of the portion of said circulation path extending through said heating compartment, said first liquid flow passage providing first and second duct portions extending upwardly within the insulation of the frontal wall portion from said lower ends, and an intermediate duct portion interconnecting said first and second duct portions, means defining a second liquid flow passage extending rearwardly and upwardly through said frontal wall portion from the upper end of the portion of said circulation path extending through said heating compartment to the upper end of the portion of said circulation path extending through said storage compartment, said recirculation path constituting a thermosiphon responsive to absorption of solar radiation transmitted via the window into the heating compartment, and heating means in thermal contact with said intermediate duct portion of the first liquid flow passage for inhibiting reverse flow of liquid when the liquid in the heating compartment is cooler than the liquid in the storage compartment.

Claim 12

A solar water heater comprising: a unitary housing structure providing a horizontal base, said housing structure further providing a liquid-filled interior thermal storage compartment and a liquid-filled interior heating compartment, each said compartment having an upper portion and a lower portion, a thermally insulating enclosure for said storage compartment, said thermally insulating enclosure including a frontal wall portion sloping upwardly and rearwardly with respect to said base, a heat transmitting window peripherally sealed to said housing structure, the window being spaced forwardly from an exterior surface of said frontal wall portion and sloping upwardly and rearwardly with respect to the base, said heating compartment being confined between said exterior surface and said window, and means defining a recirculation path for liquid extending downwardly through said storage compartment and upwardly through said heating compartment, said path defining means including: means defining a first liquid flow passage extending through the frontal wall portion between a lower end of the portion of said circulation path extending through said storage compartment and a lower end of the portion of said circulation path extending through said heating compartment, said first liquid flow passage providing first and second duct portions extending upwardly within the insulation of the frontal wall portion from said lower ends, and an intermediate duct portion interconnecting said first and second duct portions, means defining a second liquid flow passage extending rearwardly and upwardly through said frontal wall portion from the upper end of the portion of said circulation path extending through said heating compartment to the upper end of the portion of said circulation path extending through said storage compartment, said recirculation path constituting a thermosiphon responsive to absorption of solar radiation transmitted via the window into the heating compartment, and heating means in thermal contact with said intermediate duct portion of the first liquid flow passage for inhibiting reverse flow of liquid when the liquid in the heating compartment is cooler than the liquid in the storage compartment.

Claim 13

A solar water heater according to claim 10, wherein said heating means comprises a conductive heat exchanger extending between said intermediate duct portion and the upper portion of the storage compartment.

Claim 14

A solar water heater according to claim 11, wherein the exterior surface of the frontal wall portion is non-reflective and said window is of a material having a higher transparency to solar radiation than to infra red radiation reradiated from said surface.

Claim 15

A solar water heater according to claim 12, wherein the window is formed by two transparent panels spaced apart and defining an air space therebetween, each panel being peripherally sealed to the housing structure.

Claim 16

A solar water heater according to claim 11, wherein the window is of glass.

Claim 17

A solar water heater according to claim 11, wherein the window is formed by two panels, namely an interior and an exterior panel, spaced apart and defining an air space therebetween, said panels being peripherally sealed to the housing structure, the interior panel being thermally conductive and having a non-reflective exterior face, and the exterior panel having a higher transparency to solar radiation than to infra red radiation reradiated from said exterior face.

Claim 18

A solar water heater according to claim 11, wherein said means defining the first liquid flow passage comprises a metallic tube, said intermediate duct portion being defined by a portion of said tube extending into the storage compartment, said tube portion constituting said conductive heat exchanger.

Claim 19

A solar water heater according to claim 10, including means to separate said portion of said recirculation path through said storage compartment from a further circulation path for liquid through said storage compartment, said further path extending between external water flow connections to said storage compartment.

Claim 20

A solar water heater according to claim 17, wherein said separating means comprises a tubular heat exchanger mounted in the storage compartment, and extending between said external water flow connections.

Claim 21

A solar water heater according to claim 18, wherein the insulation of the thermally insulating enclosure is polyurethane, said storage and heating compartments being lined with glass fiber reinforced synthetic resin.