AU2002100327A4

AU2002100327A4 - Solar collector

Info

Publication number: AU2002100327A4
Application number: AU2002100327A
Authority: AU
Inventors: Lil Achmad Ho
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-04-26
Filing date: 2002-04-26
Publication date: 2002-05-16
Anticipated expiration: 2010-04-26

Description

AUSTRALIA

ORIGINAL

COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: Name of Applicant: Actual Inventor(s): Address for service: Solar Collector Lil Achmad Ho Lil Achmad Ho WRAY ASSOCIATES 239 Adelaide Terrace Perth, WA 6000 Attorney code: WR Details of Associated Provisional Application No(s): The following statement is a full description of this invention, including the best method of performing it known to me:- "Solar Collector" Field of the Invention This invention relates to a solar collector for collecting solar radiation.

The invention has been devised particularly, although not necessarily solely, for collecting solar radiation for subsequent conversion of the solar radiation to thermal energy. A particular application of the solar collector is in a solar hot water heater.

Background Art Typically, a solar collector comprises a collector plate which is exposed to incident solar radiation. The collector plate is usually installed in a fixed position at an orientation such that the incident solar radiation is generally normal to the plane of the collector plate when the sun is at its mid-day position. With such an arrangement, the incident radiation is disposed angularly to the plane of the collector plate during the time prior to mid-day, with the incident radiation progressively approaching the normal disposition as the sun moves towards its mid-day position. Similarly, the incident radiation is disposed angularly with respect to the plane of the collector plate after mid-day, with the angle of the incidence away from the normal disposition progressively increasing as the afternoon proceeds.

The collection of incident solar radiation is optimised when the angle of incidence is normal to the plane of the collector surface. The effectiveness of the collector diminishes with increasing angle of incidence away from the normal condition.

It is against this background that the present invention has been developed.

Disclosure of the Invention According to one aspect of the invention there is provided a solar collector having a collector surface configured such that a portion thereof is generally normal to incident solar radiation during relative movement of the sun throughout a middle part of the day.

Typically, the middle part of the day may be in the range of about 10am to 2pm.

The solar collector may comprise a plurality of such collector surfaces.

The plurality of collector surfaces may be formed as a unitary structure.

In one arrangement, the collector surfaces may be defined by an appropriately configured panel. Typically, the panel comprises a metal panel. The metal panel may be configured to define the collector surfaces by a metal working operation such as rolling or pressing.

Preferably, each collector surface is arcuate in cross section.

Conveniently, each collector surface is elongate such as a channel, although other appropriate configurations such as dimples are possible.

Preferably, the elongate collector surfaces are positioned in side-by-side relation.

According to a second aspect of the invention there is provided a solar collector comprising a collector plate defining a plurality of collector surfaces, each collector surface being configured such that a portion thereof is generally normal to incident solar radiation during relative movement of the sun throughout a middle part of the day.

According to a third aspect of the invention there is provided a solar heater comprising a solar collector according to the first or second aspect of the invention and fluid flow means for passing a fluid in heat exchange relationship with the collector surface or at least some of the collector surfaces.

Where the solar heater is for the purposes of heating water, the fluid passing in heat exchange relationship with the collector surface or at least some of the collector surfaces may comprise the water to be heated or a transfer fluid for receiving thermal energy and carrying it to the water to be heated.

Where there are a plurality of collector surfaces positioned one adjacent another, such as the case where the collector surfaces are defined by channels formed in a plate, the fluid flow means may comprise a plurality of flow ducts.

In one arrangement, each flow duct may be adjacent a junction between two neighbouring collector surfaces. In such an arrangement, each flow duct may comprise a tube nestled into a space defined on the underside of a junction between two adjacent collector surfaces.

In another arrangement, the flow ducts may be defined between two sheets connected together to form the ducts, one of said sheets comprising the panel incorporating the collector surfaces.

According to a fourth aspect of the invention there is provided a solar heater device comprising a cavity defined within a casing at least a portion of which is transparent to solar radiation, a solar collector accommodated within the cavity, a fluid flow path extending through the cavity between an inlet and an outlet, a section of the fluid flow path being positioned in heat exchange relationship with the solar collector to receive heat therefrom.

Preferably, the solar collector has a collector surface configured such that a portion thereof is generally normal to incident solar radiation during relative movement of the sun throughout a middle part of the day.

The section of the fluid flow path in heat exchange relationship with the solar collector is preferably circuitous. The circuitous section may be of any appropriate configuration, although a helical configuration is particularly suitable.

A further section of the fluid flow path may extend on the opposed side of the collector surface to the side thereof exposed to incident solar radiation.

Preferably, the casing is formed of glass or other transparent material.

Preferably, the cavity is evacuated such that a vacuum or low pressure exists therein.

Typically, there are a plurality of such solar heater devices positioned in side by side relationship, with the inlets connected to a common inlet manifold and the outlets connected to a common outlet manifold.

Brief Description of the Drawings The invention will be better understood by reference to the following description of several specific embodiments thereof, as shown in the accompanying drawings in which: Figure 1 is a schematic perspective view of a solar water heater according to a first embodiment; Figure 2 is a plan view of a solar collector of the solar water heater of Figure 1; Figure 3 is a sectional view on line 3-3 of Figure 2; Figure 4 is a fragmentary view of the solar collector; Figure 5 is a further fragmentary view illustrating the profile of the solar collector relative to incident solar radiation throughout a middle part of the day; Figure 6 is a fragmentary view of a collector of a solar water heater according to a second embodiment: Figure 7 is a schematic plan view of a solar water heater according to a third embodiment; Figure 8 is an end view of the solar water heater of Figure 7; Figure 9 is a side view of the solar water heater of Figure 7; Figure 10 is a side view of a solar heater device forming part of the solar water heater of Figure 7; Figure 11 is an end view of the solar heater device of Figure Figure 12 is a fragmentary sectional view of one end of the device of Figure Figure 13 is a sectional view on line 13-13 of Figure 10; and Figures 14, 15 and 16 illustrate the various ways in which the device receives incident solar radiation.

Best Mode(s) for Carrying Out the Invention The first embodiment, which is shown in Figures 1 to 5 of the drawings, is directed to a solar water heater 10 comprising a solar radiation collector 11, a storage tank 13 and a heat transfer circuit 15 containing a heat transfer fluid for transferring thermal energy collected by the collector 11 to water contained in the tank 13.

Typically, the heat transfer fluid comprises distilled water. Heated water contained in the storage tank 13 can be drawn therefrom as necessary in the conventional way.

The collector 11 comprises a collector plate 21 supported within a casing 23. The collector plate 21 provides a plurality of collector surfaces 25, as will be explained in more detail later. The front face 27 of the collector plate 21, which is exposed to incident solar radiation and which incorporates the collector surfaces 25, is insulated by a layer 28 which is transparent to solar radiation and which is spaced from the plate 21. In this embodiment, the layer 28 is in the form of a glass panel.

The front face 27 of the plate 21 is further insulated by an air space 29 between the glass panel 28 and the plate. The other side of the plate 21 is insulated by insulating material 31 contained within the casing 23.

The casing 23 incorporates support elements 33 for supporting the collector plate 21 at its periphery, as best seen in Figure 4 of the drawings. The casing 23 also incorporates support elements 34 for supporting the glass panel 28.

The collector plate 21 is a blackened metal plate that absorbs solar radiation. The collector plate 21 is configured to define a plurality of channels 35 disposed one immediately adjacent another, with the junctions 37 therebetween each defining a crest. Each channel 35 is of arcuate cross section, as best seen in Figures 4 and of the drawings. The channels 35 present curved surfaces to incident solar radiation and define the collector surfaces 25. Because of the arcuate configuration of the collector surfaces 25 defined by the channels 35, each surface 25 has a portion therein generally normal to incident solar radiation as the sun moves across the sky throughout the middle part of the day, typically between and 2pm. This can be best seen in relation to Figure 5 of the drawings wherein there is shown schematically angles of incident solar radiation at 1 am, noon and 2pm. From this view, it can be seen that at any time between about and 2pm, incident solar radiation is generally normal to some part of each collector surface 25. This is beneficial as it optimises the ability of the collector surface to absorb the incident solar radiation.

The heat transfer circuit 15 comprises a plurality of tubes 41 positioned in heat exchange relationship with the collector plate 21. As can be best seen from Figure 4 of the drawings, each tube 41 is nestled against the plate 21 in the space beneath the junction 37 of two adjacent channels 35. Because of the arcuate cross sectional shape of each channel 35, the junction 37 between adjacent channels 35 is at a crest and the respective tube 41 can be snugly received beneath the crest.

The tubes 41 extend in parallel relation with each other between a lower intake manifold 43 and an upper discharge manifold The tubes 41, as well as the manifolds 43, 45, are insulated by the insulation 31 on the underside of the collector plate 21.

In operation, solar radiation to which the collector 11 is exposed during the middle part of the day (say between about 10am and 2pm) can strike a portion of each collector surface 25 generally normally. As the sun moves relative to the collector 13 throughout the middle part of the day (typically between about 1Oam and 2pm), the incident solar radiation, while changing in its incoming direction relative to each collector surface 25, can continue to strike a portion of each surface generally normally, owing to the arcuate configuration of the surface. As explained earlier, this optimises the collection of incident solar radiation. The thermal energy absorbed by the plate 21 is trapped by the insulating air space 29 and glass layer 28 and transferred to the tubes 41 and the transfer fluid contained therein. The transfer fluid conveys the thermal radiation to the water contained in the storage tank 13.

The water heater 10 according to the second embodiment, which is shown in Figure 6 of the drawings, is somewhat similar to the first embodiment with the exception of the flow path for the transfer fluid. In the first embodiment, the fluid transfer circuit 15 included tubes 41. In the second embodiment, the fluid transfer circuit 15 does not utilise tubes but rather ducts 51 defined between the collector plate 21 and a second plate 53 positioned on the underside of the collector plate 21. The second plate 53 is configured to have sections 55 thereof in abutting contact with the collector plate 21 being sealingly secured thereto, and intermediate sections 57 in spaced relationship with the collector plate 21 such that the ducts 51 are defined therebetween.

Referring now to Figures 7 to 16 of the drawings, there is shown a water heater according to a third embodiment. The water heater 60 comprises a plurality of solar heater devices 61 positioned in spaced apart side-by-side relationship.

Each solar heater devices 61 has a flow path defined by flow line 63 having an inlet 65 and an outlet 67. The inlets 65 of the various solar heater devices 61 are connected to a common inlet manifold 69 and the outlets 67 are connected to a common outlet manifold The flow line 63 in each solar heater device 61 includes a first section 71 extending from the inlet end 65 and a second section 72 extending to the outlet end 67, as best seen in Figures 9, 10 and 11 of the drawings. The second section 72 incorporates a helical formation 74, as shown in the drawings.

The first and second sections 71, 72 of the flow line 63 are accommodated in a casing in the form of a tube 73 formed of material transparent to solar radiation.

In this embodiment, the tube 73 is formed of glass. The tube 73 is closed at one end 75 and is open at its other end 76 to receive a closure 77 which is in sealing engagement with the tube. The closure 77 supports the flow line 63 such that the first and second sections 71, 72 thereof are in spaced relationship to the wall of the tube 73, and the inlet end 65 and outlet end 67 are disposed exteriorly of the tube.

A solar collector plate 80 is positioned within each tube 73, with the collector plate being in heat exchange contact with the second section 72 of the fluid flow line 63.

The solar collector plate 80 is shown in Figures 7, and 12-16 but has been omitted from Figures 8 to 11 for the sake of clarity in the drawings. The solar collector plate 80 is configured to define an arcuate collector surface 81 against which the helical formation 74 of the second section 72 of the flow line 63 is in heat exchange contact.

The collector plate 80 defines two additional collector surfaces 83, one to each side of the collector surface 81, as best seen in Figures 13 and The collector surface 81 and the two additional collector surfaces 83 are each of arcuate cross section to optimise exposure to incident solar radiation during the middle part of the day, say between 10am and 2pm, as was the case with the earlier embodiments.

Each closed tube 73 is evacuated of air so as to create a vacuum condition in its cavity.

The solar heater devices 61 can receive and absorb incident solar radiation in several ways, as illustrated schematically in Figures 14, 15 and 16 of the drawings.

With reference to Figure 14, it can be seen that incident solar radiation can fall upon, and be absorbed by the inner periphery of the helical formation 74 of the second section 72 of the flow line 63, thereby heating fluid flowing therethrough.

In the drawing, the incident solar radiation is depicted by broken lines With reference to Figure 15, it can be seen that incident solar radiation can also fall upon the collector plate 80, a consequence of which is that the collector plate absorbs thermal energy. The absorbed thermal energy is trapped and transferred to the flow line 63 and the fluid flowing therethrough.

Referring now to Figure 16, it can be seen that the outer periphery of the helical formation 74 of the second section 72 of the flow path 63 is exposed to incident solar radiation throughout the day, with the particular region of exposure varying according to the relative position of the sun, as shown in the drawing.

From the foregoing, it is evident that the present invention provides a simple yet highly effective arrangement for optimising collection of incident solar radiation as the sun moves relative to the collector throughout the middle part of the day.

Improvements and modifications may be incorporated without departing form the scope of the invention.

Throughout the specification, unless the context requires otherwise. the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A solar collector having a collector surface configured such that a portion thereof is generally normal to incident solar radiation during relative movement of the sun throughout a middle part of the day.

2. A solar collector according to claim 1 wherein there are a plurality of said collector surfaces formed as a unitary structure.

3. A solar collector according to claim1 or 2 wherein the or each collector surface is elongate and arcuate in cross-section.

4. A solar heater device comprising a cavity defined within a casing at least a portion of which is transparent to solar radiation, a solar collector accommodated within the cavity, a fluid flow path extending through the cavity between an inlet and an outlet, a section of the fluid flow path being positioned in heat exchange relationship with the solar collector to receive heat therefrom. A solar heater device according to claim 4 wherein the solar collector has a collector surface configured such that a portion thereof is generally normal to incident solar radiation during relative movement of the sun throughout a middle part of the day. Dated this twenty-sixth day of April 2002. Lil Achmad Ho Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant(s)