GB2609022A

GB2609022A - Improved solar hot water system

Info

Publication number: GB2609022A
Application number: GB2110286.8A
Authority: GB
Inventors: Ghani Faisal
Original assignee: Solariskit Ltd
Current assignee: Solariskit Ltd
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2023-01-25
Also published as: GB202110286D0

Abstract

A solar thermal assembly 900 includes a solar thermal collector 502 and a hot water tank 504. The collector comprises a fluid conduit having an inlet port vertically disposed from (ideally lower than) an outlet port, and which presents a heat absorbing surface at a plurality of different angles to incident sunlight. The hot water tank is elevated with respect to the conduit and fluidly coupled thereto so that movement of fluid (e.g. water) between the two is by natural convection (i.e. thermosyphon circulation). Ideally the collector and tank are supported by a frame including handles for ease of transportation. A header tank 902 may be provided above and fluidly coupled to the hot water tank to increase the static head pressure and so better overcome hydraulic losses in the assembly. The conduit is ideally spirally coiled about flat-pack triangular support plates (200, figure 2) and housed within transparent panels to form a pyramidal collector. A one-piece cap 550 ideally seals to the panels so that heated air is trapped within an enclosure defined by the panels.

Description

IMPROVED SOLAR HOT WATER SYSTEM

The present invention relates to an improved solar hot water system and associated methods of heating fluid in a fluid storage tank.

The present inventor devised a solar thermal collector as described in international patent application PCT/6B2020/051490 (published as WO 2020/254822), which is hereby incorporated by reference in its entirety.

This disclosure describes a solar hot water system which includes a self-assembled prismatic solar thermal collector which makes improvements as compared with previous flat plate and evacuated tube hot water systems. The flat-packable prismatic design helps decarbonise heat production and is easily installed, lightweight, durable, easy to transport, resistant to damage from frost and over-heating, cheap and simple to assemble, with lower manufacturing costs.

However, even considering these important advantages, the present inventor has devised still further improvements which provide further ease of use and energy efficiency, which will further widen the access to this type of collector and improve its performance still 20 further.

According to a first aspect of the disclosure, there is provided a solar hot water system comprising: a solar thermal collector comprising a fluid conduit arranged to present a heat absorbing surface at a plurality of different angles to incident sunlight, and which has a fluid inlet port and a fluid outlet port which are vertically spaced from each other; and a fluid storage tank elevated with respect to said fluid conduit and fluidly coupled with said fluid conduit to form a thermosyphon between the tank and the conduit, so as to heat fluid in the fluid storage tank.

Optionally, the solar thermal collector further comprises a base above which the fluid conduit is mounted, a fluid conduit support member supporting said fluid conduit, and an outer housing substantially enclosing the fluid conduit.

Optionally, the outer housing comprises a plurality of panels.

Optionally, the solar hot water system further comprises a tank support which holds the tank in an elevated position.

The tank is held by the support at a height which provides sufficient head of pressure for the thermosyphoning effect.

Optionally, a frame is provided which integrates the tank support and an enclosure frame of the solar thermal collector.

Optionally, the frame is provided with handles which facilitate easy transportation of the assembly, for safe storage.

Optionally, an outlet for cold water is set in the lowest point of the base of the tank.

Optionally, the solar hot water system comprises a first connector conduit that provides a fluid coupling between a first fluid port of the tank and a first fluid port of the conduit of the solar thermal collector, and a second connector conduit that provides a fluid coupling between a second fluid port of the tank and a second fluid port of the conduit of the solar thermal collector.

Optionally, the first fluid port of the tank provides a tank inlet for hot water and is provided at an upper portion of the tank.

Optionally, the tank inlet is provided at about 60-70% of the tank height.

Optionally, the solar hot water system further comprises a header tank provided at an elevated position with respect to the fluid storage tank and which is fluidly coupled with said fluid storage tank.

Optionally, a fluid conduit couples a lower portion of the header tank with a lower portion of the fluid storage tank.

Optionally, the solar hot water system comprises a cap structure which comprises a single piece cap member configured to engage with a conduit support member and a housing.

Optionally, the cap structure comprises a seal member which reduces the amount of hot air that escapes from the top of the solar thermal collector.

Optionally, the seal member comprises an inner leg portion, an outer leg portion, an inverter U-shaped recess and a flange member at the recess which engages with side panels of the housing.

Optionally, the thermal solar collector is provided with a plurality of flexible hinge members, which comprise longitudinal slots which are adapted to receive the edges of the side panels.

According to a second aspect of the disclosure there is provided a method of heating fluid in a fluid storage tank comprising: providing a solar thermal collector comprising a fluid conduit arranged to present a heat absorbing surface at a plurality of different angles to incident sunlight, and which has a fluid inlet port and a fluid outlet port which are vertically spaced from each other; and providing a fluid coupling between the fluid storage tank and said fluid conduit to form a thermosyphon between the tank and the conduit.

The method of the second aspect may also include providing or using various features discussed in the first aspect and as can be derived from the disclosure text.

The disclosure will now be described, by way of example only, with reference to the accompanying figures in which: Figure 1 shows a base plate for a prior art solar thermal collector; Figure 2 shows a support structure for a solar thermal collector; Figure 3 shows a conduit of a solar thermal collector supported by the support structure of figure 2; Figure 4 shows the conduit of figure 3 contained by the base plate and housing panels; Figure 5 shows a solar hot water system according to a first embodiment of the disclosure including a water storage tank; Figures 6, 7 and 8 show respective top, side and front views of the solar hot water system of figure 5; Figure 9 shows a solar hot water system according to a second embodiment of the disclosure including a water storage tank and an additional header tank; Figures 10, 11, 12 and 13 show respective top, front, side and rear views of the solar hot water system of figure 9; Figure 14 shows details of a cap member used in the system of figure 5; Figures 15 and 16 show different views of a seal used for a solar thermal collector forming part of a solar hot water system according to the first or second embodiments; Figures 17, 18 and 19 show further aspects of the seal; and Figure 20 illustrates a self-assembly process of a thermal solar collector of the disclosure.

The present disclosure relates to a solar hot water system that involves a solar thermal collector of the type that comprises a fluid conduit presenting a heat absorbing surface at a plurality of different angles to incident sunlight, and which has fluid inlet and outlet ports which are vertically spaced from each other.

As an example, this type of solar thermal collector can comprise a fluid conduit formed of a coiled tubing which can be wound in a pyramidal arrangement providing fluid ports at bottom and top ends of the tubing. Figures 1-4 show one embodiment of such a solar thermal collector, as seen in the prior art disclosure of WO 2020/254822.

Figure 1 shows a square base 1. The base 1 comprises aluminium, so as to be durable yet relatively lightweight. Consequently, the base 1 can be easily transported and assembled at an installation site. The base 1 may include one or more base attachment formations 2, 2a, 2b to which a conduit support member (alternatively referred to as a column) can be attached. For example, Figure 1 shows a base attachment formation 2a at the centre of the base 1 and two smaller base attachment formations 2a, 2b aligned in one direction but each equidistantly displaced in another from the central base attachment formation 2.

Figure 2 shows a conduit support member 3 attached to the base 1 of the solar thermal collector by means of the base attachment formations 2, 2a, 2b. The conduit support member 3 includes conduit support member attachment formations (not shown) of complementary form or shape to the base attachment formations 2, 2a, 2b on the base 1, in order that the conduit support member 3 can be fixed to the base 1 without need for tools.

The conduit support member 3 of Figure 2 is shown as comprising four right angled triangular plates 200, where the edge of each triangular plate 200 opposite the hypotenuse meets in the centre of the base 1.

Sections of the right-angled triangular plates 200 comprising the conduit support member 3 have been cut out in Figure 2. Cutting out these sections from the triangular plates that form the conduit support member 3 reduces the overall weight of solar thermal collector making it cheaper to transport, as well as allowing the solar thermal collector to be positioned on the roofs of buildings or other surfaces which are unable to support the greater weight of traditional flat panel or evacuation tube solar thermal collectors.

The conduit support member 3 comprises guides 5 to support the conduit 6 (shown in figure 3), the conduit being explained in more detail with reference to Figure 3 below. For example, Figure 2 shows the conduit support member 3 comprising guides 5 in the form of ridged edges for helping to support and secure the conduit in place without the need for specialized tools.

The guides 5 comprise downwardly and inwardly sloping surfaces, so that the conduit rests on them and against an inwardly arranged part of the conduit support member 3.1n this way, the weight of the conduit helps to keep it in place in in the guides 5.

Figure 2 also shows a first housing support plate 4 for supporting a housing, which is described in relation to Figure 4, of the solar thermal collector. The first housing support plate 4 shown in Figure 2 is has a square cross section and a square opening through which the top of the conduit support member 3 protrudes. The geometry of the conduit support member 3 prevents the first housing support plate 4 from sliding down the conduit support member 3. The outwardly facing faces of the first housing support plate 4 slope inwards and upwards to provide surfaces for supporting the housing.

The conduit 6 is shown in Figure 3. The conduit 6 of Figure 3 provides a tube for carrying fluid. Figure 3 shows the conduit 6 as a coil. The conduit 6 comprises a plastics material, for instance, silicone, polyamide or low-density ethylene propylene (LDEP), resulting in a lightweight and cheaply manufactured structure. The conduit 6 is flexible, allowing the coil shape to be formed, and allowing engagement with the guides 5. The conduit 6 also preferably has a compressible cross-section, so that it is easily folded and packaged and can be incorporated in a kit for self-assembly.

The solar azimuth angle (and corresponding zenith angle) will vary during the course of the day and according to seasonal variations. Traditional flat panel solar collectors need to be positioned facing the equator and at the correct tilt to minimise losses due to variation in solar angle, and often need to be fitted with trackers to adjust the position of the array through the course of a day. However, because the self-assembled prismatic solar thermal collector has a circular cross-section, the conduit 6 passively tracks the sun as the sun moves across the sky through a wide range of solar angles. Therefore, the solar thermal collector does not need to be positioned with a great deal of accuracy and will still exhibit good performance.

Furthermore, the properties of flexibility and/or compressibility also result in improved resistance to damage caused by the freezing of the liquid in the conduit 6. For example, if the conduit 6 were made of metal and was carrying water, the water freezing, and consequently expanding, may rupture the conduit. Therefore, typical solar thermal collectors need to operate with glycol/antifreeze fluid to reduce the risk of fluid freezing in the conduit, adding cost and complexity to the system.

In addition to carrying a fluid, the conduit 6 absorbs solar radiation. This absorbed energy elevates the wall temperature of the conduit 6, which can be actively recovered by circulating a cooler fluid through it. At the bottom of the collector is an inlet port (not shown) into which cold water is delivered, for example by a pump. As the cold water makes its way to the top of the conduit 6, heat is transferred from the conduit wall to the fluid, yielding warm water at the top, which may be accessed via an outlet port 7.

Figure 4 shows a housing 8 of the solar thermal collector. The housing 8 houses the conduit 6, being formed of a plurality of panels 400 which interconnect with the base 1. Each of the plurality of panels 400 rests on a face of the first housing support plate 4 described in Figure 2.

The inwardly and upwardly sloping faces of the first housing support plate 4 each provides a surface on which each of the plurality of panels can rest. A second housing support plate 9, which is complementary in shape to the first housing support 4, caps the first housing support plate 4. By capping the first housing support plate 4, the second housing support plate 9 clasps the panels in place without the need for specialised tools to secure the housing 8. The second housing support plate 9 preferably comprises a transparent material so that radiation is not prevented from being incident on the conduit 6 by the second housing support plate 9. The panels 400 are transparent, so that radiation can transmit through the panels and elevate the wall temperature of the conduit Gas described.

By supporting the conduit 6 on the conduit support member 3, the surface area of the conduit 6 on which radiation transmitted through each of the panels 400 is incident is increased compared with a conduit laid flat on the base 1. Consequently, the efficiency of the solar thermal collector is improved compared with a solar thermal collector in which a conduit is flat, without the need for more than one conduit.

The panels are made of any suitable transparent material. They may be made of glass or another lightweight material, such as an acrylic. Again, use of a lightweight materials results in the solar thermal collector being lightweight and, thus, easily transportable and suitable for installation on edifices that may not be strong enough to support the weight of a traditional solar thermal panel. Moreover, compared with traditional solar thermal collectors, which use glass, the self-assembled prismatic solar thermal collector is less susceptible to damage during transport to the installation site and thereafter.

The panels 400 shown in Figure 4 are substantially triangular, resulting in the housings, in combination with the base 1, having the shape of a truncated square-based pyramid. The housing 8 may comprise, alternatively, triangular panels, such that the pyramid is not truncated.

The panels 400 are configured to interconnect with each other and the base 1, enclosing the conduit 6 and trapping air around the conduit 6. This trapped air provides insulation and so reduces heat loss from the conduit 6 to the environment.

In order to improve the efficiency of the solar thermal collector, the face of the base 1 facing the conduit 6 may be mirrored so that more light is reflected back to be incident on the conduit 6. It may also be possible to provide other reflective surfaces or provide reflective portions as part of the side panels 400 to further enhance this effect.

The geometry of the self-assembled prismatic solar thermal collector confers advantages over traditional solar thermal collectors, which have a planar geometry and require installation on a slope to function optimally. Firstly, the pyramidal geometry of the solar thermal collector allows it to be installed on the ground or any flat surface, such as a flat root without the need for additional mounting hardware, because the geometry of the housing 8, particularly the geometry of the housing 8 in combination with a coil conduit 6, allows the solar thermal collector to passively track the sun. Eliminating the need for additional mounting hardware reduces the cost and complexity of the system making it a viable technology in locations with poor infrastructure. The base 1 of the solar thermal collector shown in Figure 4 could be readily adapted to allow installation on a sloped surface.

Furthermore, a solar thermal collector where the panels narrow from where they connect to the base 1 means that, as air is heated and rises to the top of the solar thermal collector, the surface area of the solar thermal collector reduces. Therefore, heat loss from the solar thermal collector to the surroundings is reduced.

It will be appreciated that the present disclosure is not limited to the specific embodiments which are illustrated in figures 1-4. As explained above, the winding of the fluid conduit around the central axis of the assembly means that the solar thermal collector always presents at least a portion of its surface directly to the sunlight throughout the course of the day. However, it will be appreciated that a similar effect may be provided by different tubing or winding arrangements which provide different faces in a square, hexagonal or other arrangement.

Figure 5 shows a solar thermal collector assembly 500 according to a first embodiment of the present disclosure. A self-assembled prismatic solar thermal collector 502 is coupled with a fluid storage tank 504. The tank 504 may be insulated to keep water warm inside the 30 tank.

The assembly SOO comprises a first connector conduit 506 that provides a fluid coupling between a first fluid port 508 of the tank 504 and first fluid port 510 of the conduit 6 of the solar thermal collector assembly SOO, and a second connector conduit 512 that provides a fluid coupling between a second fluid port 514 of the tank 504 and a second fluid port 516 of the conduit 6 of the solar thermal collector assembly 500.

A tank support 518 is provided which holds the tank 504 in an elevated position with respect to the solar thermal collector 502.

The tank support 518 may comprise a frame which may upon assembly be integrated with a frame of the base member 1 of the solar thermal collector 502. The frame may be provided as a plurality of pole or rail members as part of a kit, so they can be easily assembled to form the frame.

While the original solar heater relied upon a pump to move the water through the tubing, this embodiment uses a similar solar thermal collector but omits the pump. Instead, the provision of an elevated water storage tank in fluid coupling with a flat pack prismatic solar thermal collector 502 provides a passive thermosyphon. Natural convection ensures circulation of cold water from the tank 504 to the collector 502 via the second connector conduit 512 and warm water from the collector 502 to the tank 504 via the first connector conduit 506 as the collector conduit 6 heats the fluid contained within it.

The first fluid port 508 of the tank 504 is provided at an elevated position with respect to the second fluid port 514 of the tank 504. In a preferred embodiment the second fluid port is provided at or close to a base portion of the tank 514, either at a lower surface as illustrated or at a side surface close to the base of the tank 504. The first fluid port 508 is preferably provided at an upper portion of the tank 504, preferably being provided at a position between 60-70% of the tank's height or thereabouts.

The assembly 500 provides a closed loop between the tank 504 and the heater 502, and the water cycles through the heater 502 gradually heating up the water in the tank 504. Since hot water has a lower density than cold water, it rises above any colder water so that water in the base of the tank 504 feeding the cold water outlet 514 is normally cooler than the water at the top of the tank 504.

The tank should be filled most of the way to the top. The tank 504 must be elevated by a certain amount to create a sufficient head of pressure to push the water through the heater coil 6, because there is a natural pressure drop between the inlet 516 and outlet 510 of the heater 502. Generally, the base of the tank 504 should be at around the same height as the top of the coil 6 of the collector 502, though it may be above or below it -the precise height that is required will depend on the geometry of the system and the tank shape as it may affect the overall pressure head of the system. As an example, for a coil 6 on the ground and which has approximately 23 meters of tubing, the base of the tank 504 would sit about 0.7 meters off the ground.

The tank support 518 preferably comprises a frame which to which both the tank 504 and collector 502 can be affixed, so that the whole assembly can be wheeled or pushed out into sunlight during the day and then moved back inside at night, after the sunlight has heated the water in the tank. Handles 520 can be provided as part of the frame for this purpose, and wheels (not shown) may optionally be provided as well. This ease of portability takes advantage of the fact that the assembly 500 does not need to be connected to a mains water supply (the tank 504 may be filled up by buckets), and it helps safeguard the assembly against theft or vandalism, as it can be easily stored in a secure location overnight.

Figure 6 shows a top view of the assembly 500; figure 7 shows a side view; and figure 8 shows a front view.

Figure 9 shows a solar thermal collector assembly 900 according to a second embodiment of the present disclosure. As with the first embodiment, a flat pack prismatic solar thermal collector 502 is coupled with a water storage tank 504. However, this embodiment is further provided with an additional header tank 902. A header tank conduit 904 provides a fluid coupling between the additional header tank 902 and the main storage tank 504. The conduit 904 is preferably provided between a lower portion of the additional header tank 902 and a lower portion of the main tank 504. The additional tank 902 acts to increase pressure of fluid circulating thought the solar collector (to overcome hydraulic losses). The increased head of pressure allows an outlet tap 1000 (see figures 10 and 12) to be provided at an upper portion of the main tank 504 where hotter fluid is stored to discharge hot water.

The assemblies 500, 900 of the first and second embodiments do not need any external power, pump, or physical connection to an external water supply, as the tank can be filled with buckets where mains or municipal water supplies are not available. So, it is ideal for rural settings where many households spend a large proportion of their monthly income on heating up water.

In further optional aspects of the disclosure, a one-piece assembly cap structure 550 is provided, which has a seal which reduces the amount of hot air that escapes from the top of the assembly 500, 900. The assembly cap structure 550 can be provided with any of the solar thermal collector assembly embodiments.

In the design of figures 1-4, two separate housing support plates were provided. However, as shown in more detail in figure 14, according to this aspect of the disclosure the assembly cap structure 550 comprises a single piece cap member 552 which has engagement portions adapted to receive both the conduit support structure 3 and the outer housing plates 400.

The engagement portions comprise a first set of slot members 554 protruding from a central portion of the cap member 552 and a second set of outer plate members 556 at outer portions of each side of the cap member 552, arranged such that the panels 400 can be received in the space between the outer plate members 556 and the perimeter of the cap member 552. The cap member 552 is preferably transparent to avoid blocking sunlight entering the assembly.

In addition, the cap structure 550 is provided with a seal 558 which is arranged to reduce the amount of hot air that escapes from the top of the assembly 500, 900.

The seal 558 is shown in more detail in figures 15-18; figure 1 shows a plan view and figure 16 a perspective view.

As shown in more detail in figure 18, the seal 558 has an inner leg 1800 and outer leg 1802, and an inverted U-shaped recess 1804 between the legs 1800, 1802 adapted to receive the upper edge of the side panels 400, and it sits on top of the side panels, supported by the upper edges. The U-shaped recess 1804 is continuous around the whole of the seal, even at the corners. A flange 1806 projects from the outer leg 1802, making a small angle with the lower part of the outer leg 1802, and is also continuous around the whole of the seal 558. The whole of the seal 558 may be made as a single piece of elastomeric material. The flange 1806 is the only part of the seal that contacts the cap assembly 552, which compresses the flange 1806 flatter against the outer leg 1802 as it is pushed down onto the top of the seal 558 An outer portion 1808 of the flange 1806 would be deformed more against the outer leg 1802 of the seal 558 by the inner surface of the cap member 552. The seal prevents heat being lost through the upper end of the cavity 1902.

The assembly SOO, 900 can also be provided with a plurality of flexible hinge members 1900 (see figure 19 which shows a top portion of one of the hinge members 1900). The hinge members 1900 have longitudinal slots which are adapted to receive the edges of the side panels 400 and help hold the assembly together.

In further optional aspects of the disclosure, a diffuser device 560 is provided, suitably in the form of a diffuser sheet. This helps increase the incidence of flux from sunlight into the assembly. The diffuser device 560 can be provided with any of the solar thermal collector assembly embodiments.

In the original flat pack prismatic solar thermal collector, the conduit 6 for the water flowing through the heater is enclosed by transparent panels 400, through which light is transmitted. Some of the light reflected from the base 1 in the original product is to be lost by reflection of incident light through the side panels 400.

To ameliorate this problem, an inner face of one or more surfaces of the assembly structure can be provided with a diffuser device. In a preferred embodiment, a diffuser device 560 is provided at a base 1 surface of the assembly.

The diffuser device 560 may comprise a retroreflective surface or an LED diffuser adapted to enhance the reflection of incident light beams in multiple different directions, and the conduit 6 may be arranged in a conical coil with a major and a minor diameter at opposing ends of the conical coil, and wherein the diffuser device 560 is arranged at the end of the conical coil with the major diameter.

Figure 20 shows steps in a method of self-assembly of a solar thermal collector 502. In the first step (step a), a portion of the frame 518 is provided. In this illustration only the portion of the frame 518 which is for the solar thermal collector 502 is illustrated. It will be appreciated that the frame 518 may be provided as a single device including the support members for the tank, as illustrated in figure 5; but that in alternative embodiments the frame 518 may comprise a separate collector base and tank support.

Next, at step b, the base land diffuser device 560 are provided, then, at step c, the conduit support member 3 is fixed onto the base 1. In this embodiment the plates of the support member 3 do not have cut out portions. Next, at step d, the fluid conduit 6 is coiled around the conduit support number 3, the piping of the conduit engaging with the ridges of the support. Next, at step e, the side plates 400 and are provided and the seal 558 is placed around the perimeter of the side plates 400. After that, the cap member 552 is pressed down onto the structure to press the seal in place and to help hold the structure together.

In summary, the new thermosyphon arrangement provides several key advantages which facilitate the assembly's use in less developed and/or remote areas. It provides a passive system which is easy to use. Meanwhile, the diffuser device and the new cap member with seal improve the efficiency of water heating.

In further embodiments, the disclosure may provide a solar hot water system that comprises an array of solar thermal collectors. For a given tank size, a plurality of solar thermal collectors may be provided to increase the heating effect that can be provided for that volume of fluid. Similarly, a plurality of solar thermal collectors can be provided to heat water in a larger tank or a series of tanks, which may optionally share a common outlet for drawing off hot water.

Various improvements and modifications can be made to the above without departing from the scope of the disclosure. The specification mentions water, but it will be appreciated that the principles of the disclosure may apply equally to other fluids, and the water may be treated with anti-freeze agents or other chemicals.

Claims

CLAIMS1. A solar hot water system comprising: a solar thermal collector comprising a fluid conduit arranged to present a heat absorbing surface at a plurality of different angles to incident sunlight, and which has a fluid inlet port and a fluid outlet port which are vertically spaced from each other; and a fluid storage tank elevated with respect to said fluid conduit and fluidly coupled with said fluid conduit to form a thermosyphon between the tank and the conduit, so as to heat fluid in the fluid storage tank.
2. The solar hot water system of claim 1, wherein the solar thermal collector further comprises a base above which the fluid conduit is mounted, a fluid conduit support member supporting said fluid conduit, and an outer housing substantially enclosing the fluid conduit.
3. The solar hot water system of claim 2, wherein the outer housing comprises a plurality of panels.
4. The solar hot water system of any preceding claim, further comprising a tank support which holds the tank in an elevated position.
5. The solar hot water system of claim 4, wherein a frame is provided which integrates the tank support and an enclosure frame of the solar thermal collector.
6. The solar hot water system of claim 5, wherein the frame is provided with handles which facilitate easy transportation of the assembly, for safe storage.
7. The solar hot water system of any preceding claim, wherein an outlet for cold water is set in the lowest point of the base of the tank.
8. The solar hot water system of any preceding claim, comprising a first connector conduit that provides a fluid coupling between a first fluid port of the tank and a first fluid port of the conduit of the solar thermal collector, and a second connector conduit that provides a fluid coupling between a second fluid port of the tank and a second fluid port of the conduit of the solar thermal collector.
9. The solar hot water system of claim 8, wherein the first fluid port of the tank provides a tank inlet for hot water and is provided at an upper portion of the tank.
10. The solar hot water system of claim 9, wherein the tank inlet is provided at about 6070% of the tank height.
11. The solar hot water system of any preceding claim, further comprising a header tank provided at an elevated position with respect to the fluid storage tank and which is fluidly coupled with said fluid storage tank.
12. The solar hot water system of any claim 11, wherein a fluid conduit couples a lower portion of the header tank with a lower portion of the fluid storage tank.
13. The solar hot water system of any preceding claim, comprising a cap structure which comprises a single piece cap member configured to engage with a conduit support member and a housing.
14. The solar hot water system of claim 13, wherein the cap structure comprises a seal member which reduces the amount of hot air that escapes from the top of the solar thermal collector.
15. The solar hot water system of claim 14, wherein the seal member comprises an inner leg portion, an outer leg portion, an inverter U-shaped recess and a flange member at the recess which engages with side panels of the housing.
16. The solar hot water system of any preceding claim, wherein the thermal solar collector is provided with a plurality of flexible hinge members, which comprise longitudinal slots which are adapted to receive the edges of the side panels.
17. A method of heating fluid in a fluid storage tank comprising: providing a solar thermal collector comprising a fluid conduit arranged to present a heat absorbing surface at a plurality of different angles to incident sunlight, and which has a fluid inlet port and a fluid outlet port which are vertically spaced from each other; and providing a fluid coupling between the fluid storage tank and said fluid conduit to form a thermosyphon between the tank and the conduit.