WO2008116257A1

WO2008116257A1 - Solar water heater tank systems

Info

Publication number: WO2008116257A1
Application number: PCT/AU2008/000416
Authority: WO
Inventors: Brendan Vincent Bourke
Original assignee: Rheem Australia Pty Limited
Priority date: 2007-03-26
Filing date: 2008-03-25
Publication date: 2008-10-02

Abstract

A roof mounted water heating system includes one or more tanks (14) in which the axis of the tanks is aligned with the rafters (16). The tanks can be installed inside the roof. Solar collector panels (12) can be mounted outside the roof and below the tanks. The solar collector can heat heat transfer fluid which can be circulated through a heat exchanger, for example a jacket around the tank.

Description

Solar Water Heater Tank Systems

Field of the invention

[001 ] The present invention relates generally to solar water heating systems. Background of the invention

[002] Solar heating systems are well known in the art. Such systems are typically used to capture solar radiation and heat water for domestic and other uses. Over the years, a variety of solar water heating systems have been developed to meet specific consumer needs and environmental conditions.

[003] Although the design of solar water heating systems can significantly differ, certain components are common to all systems. Thus one of the main components of a solar water heating system is a collector adapted to be erected on the roof of a dwelling or other building so that solar energy is absorbed by a circulating fluid flowing within the collector.

[004] Solar water heaters can operate by heating the water directly in the solar collector panels and transferring the water to a storage tank, or by the use of an intermediate heat transfer fluid, such as a glycol solution, in the solar collector panels and transferring the heat to the water to be heated and stored via a heat transfer means such as a brazed plate heat exchange, a heat exchange jacket surrounding the storage tank or other suitable heat exchange means. Where the heat transfer fluid is a glycol or other solution, the heat transfer fluid circuit is isolated from the water in the storage tank. The term "heat transfer fluid" will be used to refer to the fluid heated in the solar panels whether this is water or a glycol or other solution.

[005] A solar water heating system operating under a thermo-siphon principle typically includes a collector in the form of a flat panel, and a water storage container connected to the collector by two pipes - a delivery pipe supplying "cold heat transfer fluid" to the collector and a discharge pipe carrying "hot heat transfer fluid" to the storage container.

[006] The storage container is held at a height slightly above that of the collector to thereby enable the thermo-siphon flow of heat transfer fluid between the collector and the container.

[007] Any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates, at the priority date of this application. Summary of the invention

[008] The present invention provides a solar water heating system adapted to be mounted to a roof of a building; said roof having a plurality of rafters; said roof including a roof covering disposed above said rafters; the system including: heating means for supplying thermal energy to a heat transfer fluid; a delivery line and a discharge line respectively connected to said heating means for feeding thereto the heat transfer fluid and for withdrawing the heated heat transfer fluid therefrom, said heating means being adapted to be disposed on the roof of the building; and at least one storage container mounted to said roof, the heat transfer fluid transferring heat to the contents of said storage container via said delivery line and said discharge line, said storage container having a longitudinal axis, said longitudinal axis of the storage container being substantially aligned with at least one of said rafters.

[009] The heat from the heat transfer fluid can be transferred to the contents of the storage container via heat exchanger means.

[010] There can be two or more storage containers.

[011] At least one of said storage containers can be disposed above a roof covering. Alternatively, each of said containers can be disposed above the roof covering.

[012] Each of said storage containers can be disposed below the roof covering.

[013] At least one storage container can be disposed adjacent one or more of the rafters.

[014] Each of the storage containers can be disposed at the same height with respect to the heating means.

[015] Alternatively, at least two of the storage containers can be disposed at different heights with respect to the heating means.

[016] At least two of the storage containers can be connected in parallel with said heating means.

[017] A storage container can be directly mounted to at least one of the rafters.

[018] The solar water heating system can further include support means for supporting the storage container or said at least one of the storage containers, said support means being mounted to at least one of the rafters.

[019] Said support means can include a jacket surrounding at least a portion of an exterior surface of the storage container.

[020] The jacket can include a vacuum formed shell. [021] The jacket can include a double vacuum formed shell, said jacket being adapted to function as a tray for leaks from the storage container.

[022] The j acket can include insulator means.

[023] The insulator means can include a fibreglass blanket.

[024] The insulator means can include styrene preform moulding.

[025] At least a portion of an exterior surface of the storage container can be covered with an insulating material.

[026] The insulating material can be wool.

[027] The present invention also provides a storage container of a solar water heating system adapted to be mounted to a roof of a building, said roof having a plurality of rafters, said roof including a roof covering, said storage container being adapted to be mounted below the roof covering and adjacent one or more of the rafters.

[028] Said container can be mounted to said one or more rafters. [029] The storage container can be adapted to be connected in parallel.

[030] The present invention further provides a chain of storage containers of a solar water heating system, said chain including at least two storage containers, said storage containers being connected in parallel.

[031] The present invention also provides a cluster of storage containers of a solar water heating system, said cluster including two or more storage containers, at least two of said storage containers being connected in parallel.

[032] The present invention also resides in a method for assembling a solar water heating system, said system including at least two storage containers, said method including the step of connecting said storage containers in parallel.

[033] The present invention further provides a method for mounting a solar water heating system to a roof of a building, said roof having one or more rafters, said solar water heating system including at least one storage container having a longitudinal axis, said method including the step of aligning the longitudinal axis of the storage container with at least one of said rafters.

[034] The method for mounting a solar water heating system can further include the step of attaching the storage container to one or more rafters. Brief description of the drawings

[035] An embodiment or embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[036] Figure 1 is a schematic perspective view of a solar water heating system according to a first embodiment of the present invention;

[037] Figure 2 is a schematic perspective view of a solar water heating system according to a second embodiment of the present invention;

[038] Figure 3a is a schematic side view of a storage container installed in a jacket; and [039] Figure 3b is a schematic cross-sectional view of the storage container of Figure 3a. Detailed description of the embodiment or embodiments

[040] Illustrated in Fig. 1 is a solar water heating system 10 which operates under a thermo-siphon principle and includes a collector 12 in the form of a flat panel adapted to be erected on a roof of a building, and a water storage container 14 connected to the collector 12 by two pipes - a delivery pipe (not shown) supplying "cold heat transfer fluid" to the collector 12 and a discharge pipe (not shown) carrying "hot heat transfer fluid" to the storage container 14 or to a heat exchange jacket (not shown) surrounding the storage tank in the case where the heat transfer fluid circuit is separate from the potable water in the storage tank.

[041] Aligning the tank with the rafters of a sloping roof provides a greater height differential for the heat transfer fluid circuit when the heat transfer fluid exits the jacket at or near the top of the tank after transferring its heat to the water in the tank than would be the case where the tank is aligned transversely with respect to the rafters and proximate the solar panel. In particular, the height differential between the heat transfer fluid inlet to the jacket located at the lowest point of the jacket and the heat transfer fluid exit from the jacket located at the highest point of the jacket is increased due to the inclination of the tank.

[042] The storage container 14 is held at a height above that of the collector 12 to enable the thermo-siphon flow of water between the collector 12 and the container 14. Preferably the header for the heated heat transfer fluid of the solar collector is below the heat transfer fluid inlet for the jacket.

[043] As illustrated in Fig. 1, the storage container 14 is disposed under the roof of a building (not shown) below a roof covering (not shown), the longitudinal axis of the container 14 being substantially aligned with rafters 16. The storage container 14 can be positioned adjacent one or more of the rafters 16 so that the storage container 14 can be mounted to the one or more rafters 16. It will be appreciated by those skilled in the art that the storage container 14 can be mounted to the rafter(s) directly or installed in a housing (or the like) attached to the rafter(s).

[044] As illustrated in Figs. 3a, 3b, the storage container 14 is disposed in a water heater jacket 30. The jacket 30 surrounds at least a part of the exterior of the storage container 14, the remaining part of the exterior being covered with wool 32 or any other suitable insulating material.

[045] The jacket 30 can be in the form of a double vacuum formed shell having insulator means such as fibreglass blanket or styrene preform moulding.

[046] The jacket 30 also functions as a tray to capture leaks from the storage container 14. A drain line can be connected to the drain hole 36 located near the lower point of the jacket 30.

[047] Boosting can be a post or in-line Integrity gas or a standard electric heater installed in a suitable location.

[048] The solar water heating system 10 is assembled as follows. The longitudinal axis of the storage container 14 is aligned with at least one of the rafters 16. The container 14 is then attached to one or more rafters 16. It will be appreciated by those skilled in the art that any connector means well known in the prior art (eg, a bracket and a fastener) can be used for this purpose.

[049] In an alternative embodiment, the storage container 14 is installed from above the roof covering, while the jacket 30 is installed from below the roof covering, with the longitudinal axis of the storage container 14 being aligned with at least one of the rafters 16.1, 16.2. During the installation process, the storage container 14 can be supported on straps 34.

[050] The collector 12 and the storage container 14 are arranged such that piping from the outlet of the collector 12 has a continuous rise. In a preferred embodiment, the storage container is installed at the level of the top of the roof.

[051] Illustrated in Fig. 2 is a solar water heating system 20. Similarly to the system 10, the water heating system 20 includes a collector 22 disposed on the roof of a building (not shown). The system 20 further includes a plurality of storage containers 24.1, 24.2 connected to the collector 22. In general, the storage containers 24 have a shorter length than that of the container 14.

[052] As illustrated in Fig.2, the storage containers 24.1 , 24.2 are disposed below a roof covering (not shown), and the longitudinal axis of each of the containers 24.1, 24.2 is aligned with rafters 26. Similarly to the embodiment illustrated in Fig. 1, each of the storage containers 24.1, 24.2 is positioned adjacent one or more of the rafters 16 and mounted to the one or more rafters 26.

[053] Although the solar water heating system 20 illustrated in Fig.2 includes two storage containers 24.1 and 24.2 only, it will be appreciated by those skilled in the art that the number of storage containers will depend on the required capacity of the water heating system 20.

[054] The storage containers 24 can be connected to the collector 22 in parallel, the arrangement being such that at least one of the storage containers 24 is connected to the collector 22 via the delivery line (not shown), and at least one of the storage containers 24 is connected to the collector 22 via the discharge line (not shown).

[055] As shown in Fig. 2, the storage containers 24 are disposed at the same height relative to the collector 22. In other embodiments of the present invention (not shown), the storage containers 24 can be installed at different height positions. Likewise, the storage containers 24 can form two or more chains or clusters disposed at different heights with respect to the collector 22.

[056] The solar water heating system 20 is assembled as follows. The storage containers 24.1 and 24.2 are connected in series or parallel as desired, with longitudinal axis of each of the storage containers 24.1 and 24.2 being aligned with at least one of the rafters 16. The containers 24.1 and 24.2 are then attached to one or more rafters 26.

[057] Where ever it is used, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of. A corresponding meaning is to be attributed to the corresponding words "comprise", "comprised" and "comprises" where they appear.

[058] It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text. AU of these different combinations constitute various alternative aspects of the invention.

[059] While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, and all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.

Claims

1. A solar water heating system adapted to be mounted to a roof of a building; said roof having a plurality of rafters; said roof including a roof covering disposed above said rafters; the system including:

• heating means for supplying thermal energy to a fluid to be heated; a delivery line and a discharge line respectively connected to said heating means for feeding thereto heat transfer fluid and for withdrawing the heated heat transfer fluid therefrom, said heating means being adapted to be disposed on the roof of the building; and

• at least one storage container mounted to said roof, said storage container being connected to said heating means via said delivery line and said discharge line, said storage container having a longitudinal axis, said longitudinal axis of the storage container being substantially aligned with at least one of said rafters.

2. A solar water heating system as claimed in claim 1, wherein there are 2 or more storage containers.

3. A solar water heating system as claimed in claim 1 or 2 wherein at least one of said at least one storage containers is disposed above a roof covering.

4. A solar water heating system as claimed in claim 1 or 2 wherein at least one of said at least one storage containers is disposed below a roof covering.

5. A solar water heating system as claimed in any one of claims 1 to 3 wherein each of said containers is disposed above the roof covering.

6. A solar water heating system as claimed in any one of claims 1, 2 or 4 wherein each of said storage containers is disposed below the roof covering.

7. A solar water heating system as claimed in any one of claims 1 to 6 wherein said at least one storage container is disposed adjacent one or more of the rafters.

8. A solar water heating system as claimed in any one of claims 1 to 7 wherein there is more than one container and each of the storage containers is disposed at the same height with respect to the heating means.

9. A solar water heating system as claimed in any one of claims 1 to 7 wherein there are two or more storage containers and at least two of the storage containers are disposed at different heights with respect to the heating means.

10. A solar water heating system as claimed in any one of claims 2 to 9 wherein there are at least two of the storage containers which are connected in parallel with said heating means.

11. A solar water heating system as claimed in any one of claims 1 to 10 wherein said at least one storage container is directly mounted to at least one of the rafters.

12. A solar water heating system as claimed in any one of claims 1 to 10 further including support means for supporting the storage container or said at least one of the storage containers, said support means being mounted to at least one of the rafters.

13. A storage container of a solar water heating system adapted to be mounted to a roof of a building, said roof having a plurality of rafters, said roof including a roof covering, said storage container being adapted to be mounted below the roof covering and adjacent one or more of the rafters.

14. A storage container as claimed in claim 13, said container being adapted to be mounted to said one or more rafters.

15. A storage container of a solar water heating system, said storage container being adapted to be connected in parallel.

16. A chain of storage containers of a solar water heating system, said chain including at least two storage containers, said storage containers being connected in parallel.

17. A cluster of storage containers of a solar water heating system, said cluster including two or more storage containers, at least two of said storage containers being connected in parallel.

18. A method for assembling a solar water heating system, said system including at least two storage containers, said method including the step of connecting said storage containers in parallel.

19. A method for mounting a solar water heating system to a roof of a building, said roof having one or more rafters, said solar water heating system including at least one storage container having a longitudinal axis, said method including the step of aligning the longitudinal axis of the storage container with at least one of said rafters.

20. A method for mounting a solar water heating system as claimed in claim 19 further including the step of attaching the storage container to one or more rafters.

21. A solar water heating system as claimed in claim 12 wherein said support means includes a jacket surrounding at least a portion of an exterior surface of the storage container.

22. A solar water heating system as claimed in claim 21 wherein said jacket includes a vacuum foπned shell.

23. A solar water heating system as claimed in claim 21 wherein said jacket includes a double vacuum formed shell, said jacket being adapted to function as a tray for leaks from the storage container.

24. A solar water heating system as claimed in any one of claims 1 to 12 or 21 to 23 wherein at least part of the exterior of the storage container is covered with an insulating means.

25. A solar water heating system as claimed in claim 24 wherein said insulator means is mead from a material containing one or more of:

wool;

a fibreglass blanket;

styrene preform moulding;

26. A solar water heating system as claimed in any one of the preceding claims, including solar collector means adapted to be mounted below the heat transfer fluid inlet of the heat transfer fluid jacket of the tank.