Solar thermal collector
Patent Information
- Application Number
- AE202603210
- Authority / Receiving Office
- AE · AE
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-03-27
- Filing Date
- 2025-03-24
Smart Images
Figure ABST_ABST
Abstract
Description
SOLAR THERMAL COLLECTOR TECHNICAL FIELD The present invention concerns an improved solar thermal collector, a system comprising said solar thermal collector, a kit for assembling said solar thermal collector and methods of constructing said solar thermal collector. BACKGROUND Most commercially available solar thermal collectors have large, flat or tubular designs. This results in them being heavy and requiring precise positioning. Therefore, there are numerous circumstances in which they are not suitable for use. In addition, most existing systems are costly and require expert installation. Many existing solar hot water solutions are also considered bulky and unattractive, and are prone to overheating and damage by hard water. The bulky nature of existing solar thermal collectors results in higher storage and transport costs, increasing the environmental burden of the devices. Households across the globe, particularly those in countries where the current infrastructure does not support the majority of solar panels that are currently commercially available, need to be able to utilize solar energy. For example, US2402326A describes a solar heater for use in tropical areas for the heating of water, that can be set up on a lot or other piece of ground rather than on a roof or building top where the same is ordinarily inaccessible for the purpose of repairs, replacements, etc. However, there is a need for flat-pack solar thermal collectors having an easy and simple construction without needing complex instructions, an expert or additional tools, that can efficiently gather solar energy, in a wide range of locations. WO2010 / 013028A2 describes a solar collector configured for solar radiation absorption and conversion into heat, in either flat panel or 3-D hemispherical, conical or similar format. The collector consists of a modular laminated sandwich of a translucent outer panel, such as a single layer or multi-wall sheet, surmounting a profiled backing tray, with a channel recess or channel to receive a coiled conduit, such as of flexible wall plastics material, for a heat exchange fluid medium, conveniently water, with an optional backing layer profiled for conduit location and support. US4385624A describes a solar energy water heating unit for a swimming pool, which heats water from a pool by passing the water through a series of spiral hoses mounted on a supporting surface. The supporting surface itself is mounted on a platform raised from the ground and is cone-shaped to allow for at least a portion of each hose line to be exposed to the sun at all times of the day, with the spiral hose lines mounted in spiral grooves provided on the supporting surface. DE202005009769U1 describes a demountable solar energy collector, for example for water heating, which has segments with profiled edges supporting flexible pipes and forming a quadratic or half spherical shape. The segments are secured between upper and lower support rings, and the segments are made of metal, wood or plastic. The system can be assembled as a stand alone structure or forms part of a tree type structure. Alternative solar thermal collectors, such as those described in WO2020 / 254822, can be flat-packed and comprise a coiled conduit. The coiled arrangement of the conduit is achieved using ridges in a column, which guide the conduit around the outer edge of the column and then up a distance before going around the outer edge of the column again. The ridges space the portions of the conduit extending around the outer edge of the column apart from one another, which allows the top surface of the conduit to absorb energy. GB2609022A describes a solar thermal assembly including a thermal collector and a hot water tank. The thermal collector comprises a fluid conduit having an inlet port vertically disposed from 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 between the two is by natural convection. The present invention therefore aims to provide an improved solar thermal collector which can be easily assembled into the correct arrangement and functions with improved efficiency. SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a solar thermal collector that may be adapted to be assembled from a flat pack configuration. The solar thermal collector comprises a conduit configured to carry fluid and to absorb radiation. The solar thermal collector also comprises a column configured to support the conduit, the column comprising guides for securing the conduit in place such that the conduit forms a coil. The spacing of the guides may mean that adjacent portions of the conduit are not in contact with one another. The adjacent portions of the conduit are adjacent to one another in a vertical direction and the adjacent portions are vertically spaced from one another. The spacing of the guides may mean that over 80% of the vertical space between adjacent portions of the conduit does not align in the vertical direction with a vertical space between adjacent portions of the conduit on the diametrically opposite side of the coil. By “adjacent portions” it is meant the portions of the conduit that are vertically adjacent to one another. The adjacent portions will be connected to each other around the column (i.e. will be part of a continuous path), but are spaced vertically from one another. Thus, extending up the height of the column at any point around its circumference are portions of conduit adjacent to one another, each separated by a space. These portions may be parallel to one another. The coil may be spiral. The space between adjacent portions of the conduit may be constant along the majority of its length, optionally along all of its length. The conduit may increase in height gradually, continuously and / or consistently as it passes around the column. By “align” it is meant that the space does not exactly align with or is not entirely within the height of the space between adjacent portions of the conduit on the diametrically opposite side of the coil, when looking at the coil horizontally. Thus, a portion of the conduit may be positioned in the same horizontal plane as a vertical space between adjacent portions of the conduit on the opposite side of the coil. The space between adjacent portions of the conduit in the coil may not overlap at all in the vertical direction with a space between adjacent portions of the coil on the opposite side thereof when looking at the coil horizontally. Alternatively, the spaces between adjacent portions of the conduit in the coil may only partially overlap in the vertical direction with the corresponding spaces on the opposite side of the coil. For example, a space between adjacent portions of the conduit in the coil may overlap in the vertical direction with a corresponding space on the opposite side of the coil by less than 25% of the first space, preferably less than 15%, when looking at the coil horizontally. The inventors have surprisingly found that arranging the coil in this manner means that solar radiation can not pass straight through the coil, using the vertical spaces between the portions of the conduit. This results in reduced optical losses and increases the efficiency of the solar thermal collector. However, the inclusion of a vertical space means that more of the surface of the conduit is exposed to light, and that light can enter the coil and fall on an internal surface of the conduit. There is therefore a space between adjacent portions of the conduit in the vertical direction. In other words, the upper surface of one portion of the conduit is below (and so not in line with) the level of the lower surface of the portion above, in the direction of the height of the solar collector. The space between adjacent portions of the conduit may be thinner than the portions of the conduit in the vertical direction. The adjacent portions of the conduit may also be offset from one another in the horizontal direction, such that the coil narrows up the height of the solar collector. In order to obtain the necessary increase in efficiency, over 80% of the vertical space between adjacent portions of the conduit does not align with a space on the opposite side of the coil. This can be measured along the length of the space (parallel to the path of the conduit) and so over 80% of this length does not align with a space on the opposite side of the coil. Preferably over 90% and more preferably over 95% of the vertical space between adjacent portions of the conduit does not align with a space on the opposite side of the coil. In other words, over 80% of the space in the vertical direction between adjacent portions of the conduit does not align with any space in the vertical direction between adjacent portions on the opposite side of the coil. None of the space between adjacent portions of the conduit, along the length of the space, may align with a space on the opposite side of the coil. Thus, in this embodiment, any space between adjacent portions of the conduit selected will not align with a space on the opposite side of the coil. The terms ‘height’ or references the ‘lower’ and ‘higher’ are in relation to distance from a base of the solar collector or a surface on which the solar collector is resting, perpendicular thereto. The “vertical” direction is that perpendicular to a base of the solar collector or a surface on which the solar collector is resting. The term ‘optical loss’ can be taken to mean solar radiation escaping the solar thermal collector. The column may comprise a plurality of plates. The column may be formed from any number of plates. The plates may be any suitable size, thickness, and / or material. The plates may be between 1 and 10 mm thick, preferably between 1 and 6 mm thick. The use of plates allows the solar thermal collector to be flat-packed. The column may be transparent. The transparency of the column allows the conduit coil to be supported but does not block solar radiation from reaching the conduit. Alternatively, the column may be opaque and may be dark in colour. An opaque column dark in colour will absorb solar radiation, increasing ambient temperature within the solar collector thus reducing heat losses from the coil. The column may be formed from two intersecting plates. The plates may intersect to form a cross-shaped cross-section with four arms. The intersection may be at the middle of both of the plates. Alternatively, the column may be formed from a plurality of plates arranged to all have one edge in the middle of the arrangement to form a cross- or a star-shaped cross-section. The plates are preferably connected to one another without the use of other fasteners, such as screws or bolts. The plates may fit together using slots. There may be complementary slots on each of the plates that allows them to be attached to one another without the requirement of other fasteners. The guides for securing the conduit in place may be formed from indentations along at least one edge of the one or more plates. This creates a ridge structure down said edge of the plate, such that the conduit can fit into each of the indentations. The indentations may be along opposite edges of each plate. This means that in an embodiment in which the plates intersect to form a cross-shaped cross-section, there are indentations along the end of each arm thereof. The guide may be formed from any number of indentations. Preferably the guide may be formed from 1 to 50 indentations, 10 to 30 indentations or 15 to 25 indentations. The number of guides may depend on the size of the conduit and / or the size of the solar thermal collector. The indentations may be a curved shape and may have a diameter larger than the diameter of the conduit. The guides of the column support the conduit and create a coil, which allows the conduit to absorb solar radiation from all angles. Therefore, the solar thermal collector can function at all times of the day and year (i.e. changes in solar radiation due to seasonal variation) as the radiation can be collected from a variety of directions. The location of the guides may be different on each edge of the column. The first guide that the conduit reaches on the column may be the closest to the base, with the start of the guides gradually increasing in height from the base along the path of the conduit. However, the spacing between each indentation of each guide may be the same. The guides may secure the conduit to the column at an angle to the horizontal. Said angle of the conduit results in a continuous increase in height relative to the base of the solar thermal collector as the conduit progresses around the column. Thus, the lowest indentation of the guide may be at different heights on the different edges of the arms of the column. Specifically, the first arm of the column may have the guide starting at the lowest height, the second arm may then have the guide starting at the second lowest height, and so on. This allows the conduit to continuously increase in height from the base as the conduit is placed in the guide of each arm of the column as the coil is formed. The continuous increase in the height of the conduit as it passes between the guides can position the conduit at the same height as a space between adjacent portions of the conduit on the opposite side of the coil, in any horizontal plane. The solar thermal collector may comprise one or more reflective sheets. The one or more reflective sheets may be positioned within the coil and angled to direct radiation towards the conduit. The one or more reflective sheets may be flat or may be curved. The one or more reflective sheets may form a cone structure or a pyramid structure. The one or more reflective sheets may be made of a reflective material or a non-reflective material with a reflective coating on the side facing the conduit. The one or more reflective sheets preferably do not come into direct contact with the conduit, as this would stop or reduce the ability of the reflective sheet to reflect the light back on to the conduit. Thus, the reflective sheets do not extend up to the base perimeter of the column. Advantageously, the reflective sheets reduce optical losses by reflecting solar radiation that did not hit and get absorbed by the conduit on its first pass through the coil back on to the conduit. Therefore, the reflective sheet improves the amount of solar radiation that can be absorbed by the conduit and makes the solar thermal collector more efficient, as it allows the internal surface of the conduit to also absorb solar energy. The reflective sheets may also absorb solar radiation, thereby increasing the ambient air temperature within the solar collector and reducing heat loss from the coil. In a preferred embodiment of the present invention, the one or more reflective sheets comprise both reflective and non-reflective material on the side facing the conduit. The non-reflective material absorbs solar radiation, thereby increasing the ambient air temperature within the solar collector. The reflective material, as well as absorbing some solar radiation of its own, reflects the absorbed energy onto the internal surface of the conduit. The non-reflective material may be coloured black. The non-reflective material may be matte or glossy. Preferably, the non-reflective material is matte. The reflective material may any suitable reflective material, such as a metal, for example aluminium. The reflective material may be coloured silver or white. The non-reflective and reflective material may be arranged on the surface of the one or more reflective sheets in any suitable pattern, such as dots, stripes, triangles, or any other geometric pattern. The ratio of non-reflective material to reflective material on the surface of the one or more reflective sheets may be between 90:10 and 10:90. Preferably, there is a greater amount of non-reflective material than reflective material on the surface of the one or more reflective sheets, as this increases the temperature within the thermal collector and reduces losses through the spaces between adjacent portions of the conduit. Thus, the most preferred ratio of non-reflective material to reflective material on the surface of the one or more reflective sheets may be between 90:10 and 50:50, preferably between 80:20 and 55:45. Advantageously, when the reflective sheets comprise both reflective and non-reflective material on the side facing the conduit, the efficiency of the thermal collector is greatly improved, owing to the cooperative effect of the heat absorption provided by the non-reflective material, and the heat reflection provided by the reflective material. For example, if the reflective sheet surface was fully reflective, too much of the energy that is reflected by the sheet would escape, whereas if the reflective sheet surface was fully absorbent (i.e. non-reflective), solely heat absorption would occur. Therefore, a combination of both reflective and non-reflective material on the sheet surface significantly reduces energy losses, whilst also improving efficiency and heat absorption by reflecting absorbed heat onto the conduit. The one or more reflective sheets may be connected to the column. The one or more reflective sheets may be connected to the plates of the column and may extend between said plates. One or more reflective sheets may extend between every plate. Thus, in an embodiment in which the plates form a cross-shaped cross-section, a reflective sheet may extend between each of the adjacent arms of the cross. The one or more reflective sheets may be triangular. This allows them to be positioned between plates of the column at an angle. The one or more reflective sheets may be attached to the column through slots in the column, into which a portion of the reflective sheet can extend. Said portion of the reflective sheet may be shaped to fit into said slot, e.g. as a tab. The one or more reflective sheets may be positioned up to any height of the column, preferably extending more than 75% of the height of the column. The one or more reflective sheets may be attached at any point along the height of the column. The solar thermal collector may comprise a base. The base may be connected to the column and may comprise connecting means for holding the column in position. The connecting means may be one or more slots in the base, into which one or more bottom portions of the column can be inserted. The bottom portions of the column may be shaped to fit into said slots. The column may additionally or alternatively be fixed to the base via clips or other mechanical fastenings means. The column may be connected to the base such that the edges are close to the perimeter of the base. The edges of the column should not contact the perimeter of the base. If the base is rectangular and the column is cross-shaped, the edges may be offset from the corners of the base. The edges may point towards the side of the base, rather than a corner thereof. The one or more slots in the base may have lengths which correspond to the lengths of the bottom portion(s) of the column. Preferably, the slot lengths are designed such that the column can only be connected to the base in the desired orientation. For example, one slot may be a different length to the others, which corresponds to a particular bottom portion of the column. Additionally or alternatively, the shape of the slots may be such that the column can only be connected to the base in the desired orientation. This is particularly beneficial if the column is formed from a plurality of plates, as the plates can then only be assembled in the correct arrangement. The one or more slots may form a cross on the base. The slots in the base may be through the entire depth of the base. The base may comprise secondary connecting means for holding the one or more reflective sheets in position within the coil. The secondary connecting means may comprise slots. The slots may correspond to shaped portions such as tabs on the lower edge of the one or more reflective sheets. The slots may be angled to assist in correctly positioning the one or more reflective sheets. There may be a plurality of secondary connecting means for each reflective sheet to allow flexibility in the height and / or angle of the reflective sheets. In an alternative embodiment, the secondary connecting means may comprise an indent or ridge in the base. In an alternative embodiment the secondary connecting means may comprise an adhesive material. The base may be formed from a polymeric material. The polymeric material may be any suitable polymeric material that is resistant to UV, prolonged outdoor exposure and impact (e.g. from hail stones). Suitable materials include ASA, Nylon and polyethylene. Preferably, the material may be strong enough to support the solar thermal collector but light enough to allow the solar thermal collector to be used in most locations, for example on a roof which cannot hold a large weight. The base may be formed from a single piece of material. Advantageously, the base being formed from a single piece of material reduces any air flow and / or heat loss which may occur through gaps in a base formed from multiple parts. In addition, this means that it is very easy to assemble the solar thermal collector in the correct arrangement, without the use of any tools, thereby improving the accessibility of the solar thermal collector. The base may be any shape. The base may be circular or a polygon, for example the base may be triangular, rectangular or square. Preferably, the base is square or rectangular. The base may be any size. Preferably, the base is large enough for the solar thermal collector to produce a sufficiently large amount of heated fluid but small enough that the solar thermal collector can be easily transported and placed in almost any location. Preferably, the thickness of the base is great enough that the solar thermal collector is provided with sufficient support, for example on a slightly uneven terrain, but thin enough to not provide unnecessary weight to the solar thermal collector. The base may be a square or rectangle, in which each side is between 30cm and 1m long, preferably between 40cm and 75cm long. The base may comprise a honeycomb structure on the side opposite that connected to the column. The honeycomb structure may form pockets of air, which can trap air under the base of the solar thermal collector, thereby reducing heat loss through the base of the solar thermal collector. The honeycomb structure can also add mechanical rigidity to the base. The base may have additional attachment means on the side opposite that connected to the column which may aid in securing the solar thermal collector to any surface. For example, at least part of the surface of the base that is in contact with the surface on which the solar thermal collector is placed may be textured to increase grip. This may be advantageous if the collector is placed on a slight slope and / or to reduce movement of the collector in windy conditions. The base may comprise one or more indents on the side opposite that connected to the column to allow stacking with other identical bases. This allows efficient stacking of the bases to aid in storage and therefore reduce space and costs during transport. Connection means may also exist on the outer edges of the base to facilitate the placement of two or more solar thermal collectors adjacent to each other, for example for creating a system comprising a plurality of solar thermal collectors. The base may comprise an aperture for a clip to anchor the conduit before it reaches the column. This allows the conduit to be positioned correctly for use with an inlet fitting and / or the column. It provides the additional advantage of securing the conduit in place to improve the ease of assembling the solar thermal collector. The solar thermal collector may comprise a housing that surrounds the conduit coil and the column. The housing may comprise one or more side panels. The side panels may be made of glass, plastic, or any other suitable material. The one or more side panels may be transparent or may be partially transparent. The side panels may be smooth on the external surface and matte on the internal surface facing towards the conduit coil. The panels may be attached to each other such that there is no gap between the panel edges. This can be achieved using a flexible component with a hinge that connects to each adjacent panel. The housing may further comprise a frame structure which supports the panels. The frame structure may be made of plastic to reduce heat loss. The one or more side panels may form a housing with a dome structure, an orthogonal structure or a pyramid structure. Preferably, the side panels may form a housing with a pyramidal structure. The housing advantageously allows solar radiation to pass through the panels to reach the conduit but reduces airflow around the conduit coil. This reduces any heat loss and increases the efficiency of the solar thermal collector. It also increases the maximum temperature that the fluid can be heated to using the collector. The one or more side panels may have one or more holes through which the conduit can enter and exit the housing via an inlet fitting and an outlet fitting. The one or more holes for the inlet and outlet fittings may be fitted with a seal. The inlet fitting and outlet fitting may be present on the same side of the solar thermal collector or may be on different sides of the solar thermal collector. The inlet fitting and outlet fitting secure the conduit in place relative to the housing and reduce airflow into the solar thermal collector. The inlet fitting may be positioned near the base of the thermal solar collector so that the fluid enters the conduit at the bottom of the coil, next to the base. The outlet fitting may be positioned near the top of the solar thermal collector so that the fluid exits the conduit from the top of the coil. In this way, the cold fluid may enter near the base of the solar thermal collector and heat up as it flows through the conduit coil before leaving near the top of the solar thermal collector. As hot water rises this aids in the natural flow of the water through the conduit. The inlet fitting and outlet fitting may be shaped to attach to any suitable piping or system to allow the solar thermal collector to heat fluid. The housing unit may comprise a cap at the top of the solar thermal collector. The cap may be made of plastic or any other suitable material. The cap may be positioned above the column of the solar thermal collector. The cap may be designed to connect to the top of the column. The cap may be connected to the one or more side panels. The cap may comprise an additional seal or extended edge, which extends over the top of the side panels to reduce air flow between the cap and the upper edge of the one or more side panels. This advantageously reduces heat loss through any gaps and reduces airflow which may result in heat loss. The cap may be transparent or partially transparent. The cap being transparent advantageously allows solar radiation to enter the solar thermal collector from directly above. In one embodiment, the solar radiation that enters from directly above will pass through the centre of the coil and reach the reflective sheets, before being reflected off a reflective sheet and hitting the conduit. Thus, in addition to their individual advantages, the combination of the transparent cap and reflective sheet result in an increase in the solar radiation that can be absorbed by the conduit to aid heating of the fluid inside. The housing unit may be a distance of approximately 0.5 cm to 20 cm away from the conduit coil. Preferably, the housing unit is not in direct contact with the conduit, to reduce heat loss from the thermal solar collector. Preferably the housing unit is less than 15 cm away from the conduit coil to reduce the air volume surrounding the coil. The base of the solar thermal collector may have one or more raised edges, seals and / or slots. The one or more raised edges, seals and / or slots may connect to the housing. The one or more raised edges, seals and / or slots may extend around at least part of the perimeter of the base. The one or more raised edges, seals and / or slots may extend around the entire perimeter of the base. The one or more raised edges, seals and / or slots may be positioned slightly inside the perimeter of the base. The raised edges, seals and / or slots may be angled. The raised edges, seals and / or slots may be angled at a degree that allows the preferred placement of the housing. The raised edges, seals and / or slots may be angled inwards towards the centre of the base. This angle may match the angle of the housing side panels when in position around the column. The raised edges, seals and / or slots advantageously reduce air flow and therefore heat loss from the solar thermal collector. In addition they reduce any dust, sand and / or dirt from entering the solar collector, which would impact the efficiency of the solar thermal collector. The base may have one or more corners. The base may have a raised hood portion at one or more corners thereof on the side that connects to the column. The base may have a raised hood portion at all corners thereof. The raised hood portion may connect to the housing. The raised hood portions may cover the connection between the housing and the base. The raised hood portion may be angled to cover any gaps where the frame of the housing meets the base. This reduces airflow into the solar thermal collector, therefore reducing heat loss from the collector. This improves the efficiency of the solar thermal collector. The improved housing and base of the solar thermal collector of the present invention results in improved sealing of the collector. This advantageously reduces air or wind entering the solar thermal collector, which reduces heat loss and results in an improved performance of the collector. The base may be formed from a single piece of polymeric material which includes the raised edges, seals and / or the hooded corner portions. The base may be formed from a piece of polymeric material to which the raised edge around the perimeter and / or the corner hood portions and / or a seal can be attached later. The conduit may be any diameter, length, thickness, and made of any suitable material. The conduit outer diameter may be between 5 and 25mm, preferably between 7 and 20mm. The conduit inner diameter may be between 2 and 20mm, preferably between 5 and 15mm. Preferably the conduit is a dark colour, most preferably the conduit is black. The external surface of the conduit may be matte. Any number of revolutions around the column, by the conduit, may be made to form the coil. Preferably, the number of revolutions is the same as the number of indentations forming the guide along each edge of the column. The length of the conduit may be between 5 m and 50 m, preferably between 10 m and 40 m, preferably between 20 m and 30 m. Preferably the length of the conduit is sufficient to form the coil and extend into and out of the solar thermal collector via the input and output fittings. The diameter of the base of the coil may be greater than the diameter of the top of the coil. Preferably the diameter of the base of the coil is slightly less than the diameter / width of the base (e.g. 80-95% thereof). The column and the coil may form a pyramid shape or a truncated pyramid shape. The decrease in diameter of the conduit coil as it increases in height above the base allows the top surface of the conduit to absorb solar thermal energy as it is not blocked by the adjacent portion of conduit above. This coil format aids in increasing the amount of solar radiation that can be absorbed by the conduit from all angles. Preferably, the base of the coil is not directly in contact with the base to reduce heat loss through the base. The conduit may be filled with water and / or an anti freeze fluid (e.g. glycol). The conduit may be filled with any suitable liquid. The conduit may be able to heat the liquid to approximately 80°C. According to a second aspect of the present invention, there is provided a system comprising a plurality of solar thermal collectors of the present invention. The system may comprise two or more solar thermal collectors. The plurality of solar thermal collectors may be connected via connection means on the bases of the solar thermal collectors. The plurality of solar thermal collectors in the system may be arranged such that the bases of each collector are not in direct contact, to reduce any blocking of solar radiation from any of the solar thermal collectors. The system may involve connecting the plurality of solar thermal collectors to a shared pipe system. The system may involve connecting the plurality of solar thermal collectors to a single hot water storage unit via a shared pipe or individual piping. The plurality of solar thermal collectors may be connected in series or in parallel, preferably in series such that the outlet of one unit connects to the inlet of the next. According to a third aspect of the present invention, there is provided a flat-pack kit for assembling a solar thermal collector of the present invention, comprising a conduit and a column. The flat-pack kit may further comprise any one or more of the base, the one or more reflective sheets, the housing, the conduit, and the clip discussed above. A kit according to this aspect of the present invention provides an easily transportable means to create a solar thermal collector on-site, without requiring additional tools. This advantageously improves the ease of assembly. Additionally, the flat-pack nature of the solar thermal collector and its kit reduces the storage and transport costs and well as the environmental impact of transporting larger collectors of the prior art. The flat-pack design also reduces breakage rates during transportation, which is an issue with current solar collectors, especially tubular design solar collectors. According to a fourth aspect of the present invention, there is provided a method of constructing a solar thermal collector of the present invention, comprising assembling the kit of the third aspect. The method of constructing the solar thermal collector may be limited by the slots in the base and / or column, such that the components can only be assembled in the correct orientation. The method of constructing the solar thermal collector may involve one or more of assembling the column, connecting the column to the base, connecting the one or more reflective sheets to the column and / or to base, connecting the clip to the base, arranging the conduit around the column using the guides to form a coil, and assembling the housing around the conduit coil such that the inlet and outlet fittings are in place. The method of constructing the solar thermal collector may further involve connecting the conduit to additional piping and / or water storage facilities. The method of constructing a solar thermal collector of the present invention can occur at the final desired site of the solar thermal collector. The method of constructing a solar thermal collector of the present invention can occur at a different local site to the final desired site of the solar thermal collector. Due to the light-weight design of the solar thermal collector, the collector can be easily relocated after construction. Relocation can occur immediately after construction or at any time after. The solar thermal collector may be considered as portable. This advantageously allows the solar thermal collector to be moved depending on multiple factors, for example, the time of year, a change in desired use, when moving house, and / or moving for theft prevention. The solar thermal collector of the present invention and / or the system comprising a plurality of solar thermal collectors of the present invention may be connected to a pump, which may be connected to a power source. The solar thermal collector of the present invention and / or the system comprising a plurality of solar thermal collectors of the present invention may be connected directly to a water storage unit. The solar thermal collector of the present invention and / or the system comprising a plurality of solar thermal collectors of the present invention may be used in a passive or active system. The versatility of the solar thermal collector allows the collector to be used in the most efficient mode depending on the specific circumstances of each collector. Any of the features discussed above in relation to one of the aspects of the present invention can equally apply to the other aspects of the present invention. DETAILED DESCRIPTION The invention will now be more particularly described with reference to the following examples and figures, which are not intended to be limiting on the scope of protection provided, in which; Figure 1 illustrates a first embodiment of a solar thermal collector; Figure 2 illustrates a side view of the first embodiment of a solar thermal collector; Figure 3 illustrates the top side of the base of the solar thermal collector; Figure 4 illustrates the bottom side of the base of the solar thermal collector; Figure 5 illustrates two plates which form the column of the solar thermal collector; Figure 6 illustrates the column, reflective sheets and base of the solar thermal collector; Figures 7a and 7b illustrate a side view of a conduit coil of a solar thermal collector of the prior art and of the first embodiment; Figure 8 illustrates a top view of a solar thermal collector; and Figure 9 illustrates different types of reflective sheet, according to an embodiment of the present invention. Figure 1 illustrates the solar thermal collector 1 of the present invention. The conduit 2 is arranged in a coil structure using the guides of the column 3. The column 3 comprises two intersecting plates, creating four arms extending away from the centre in a cross-shaped cross-section with opposing edges of each plate comprising the guides. Between the arms of the column 3, reflective sheets 7 are secured with the reflective side facing towards the conduit 2. The column 3 is positioned on a base 6. The base 6 has a raised outer edge 11 and corner hood portions 12. A housing 17 surrounds the coil and is formed from a frame 13, side panels 14 and a cap 15. The frame 13 is in contact with the corners of the base 6 and extends upwards to surround the conduit 2. The frame 13 holds side panels 14 in place around the conduit 2. The side panels 14 allow solar radiation to pass through and reach the conduit 2 and help retain the thermal radiation within the solar thermal collector 1. An inlet fitting 8 and an outlet fitting 9 allow the conduit 2 to access the external environment, through the side panels 14. A clip 10 is located on the base 6 to aid in securing the conduit 2 to the base 6 in the correct position. A cap 15 is located at the top of the solar thermal collector 1, above the column 3. The cap 15 has an extended side 16 which extends below the cap 15 over the top portion of the side panels 14. The side panels 14 extend from the base 6 up to the cap 15. Figure 2 illustrates a side view of the solar thermal collector 1. The conduit 2 is arranged around the column 3 to form a spiral coil. Only the conduit 2 on the closest side can be seen. The conduit 2 gradually increases in height relative to the base 6 as it passes around the column 3. The reflective sheets 7 extend between arms of the column 3. The edge of one arm of the column 3 is shown in the middle of the figure. The inlet fitting 8 and outlet fitting 9 extend away from the solar thermal collector 1. The extended sides of the cap 15 extend down below the top of the side panel and the raised edge of the base 6 extends above the lower edge of the side panel, resulting in a housing 17 which is resistant to internal air-flow from wind. This reduces the loss of heat from inside the solar thermal collector 1. Figure 3 illustrates the base 6 of the solar thermal collector 1. The top side of the base 6, i.e. the side that is in contact with the column, is shown. The base 6 is square. The base 6 has a raised edge 11 along the perimeter which rises above the height of the main portion of the base 6. Inside the raised edge 11 of base 6 is an angled slot 32. The angled slot 32 is at a suitable angle and depth to contain the lower edge of the housing. The corners of the base 6 have a raised corner hood portion 12, which is raised higher than the raised edge 11. The corner hood portion 12 is angled to cover any gaps where the frame of the housing meets the base 6. The base 6 has four distinct column-connection slots 30a, 30b, 30c, 30d for correctly positioning and attaching the column in place. The column-connection slots 30a, 30b, 30c, 30d are designed so that the column can only be assembled in the correct arrangement to result in the guides being correctly placed to form a consistently angled conduit coil. The column-connection slots 30a, 30b, 30c, 30d are designed to allow tabs at the base of the column to fit in place. The base 6 has four reflective sheet slots 31 which act as a secondary connecting means for holding the reflective sheets in position. The reflective sheet slots 31 are located between the column-connection slots 30a, 30b, 30c, 30d such that each reflective sheet can be positioned between two adjacent arms of the column. The base 6 also has an aperture 33, to which a clip can be connected. Figure 4 illustrates the base 6 of the solar thermal collector. The bottom side of the base 6, i.e. the side which is opposite to the side in contact with the column, is shown. This side of the base 6 has a honeycomb structure 41. The honeycomb structure 41 allows pockets of air to form under the solar thermal collector to insulate it from the ground and reduce heat loss. The underside of the column-connection slots 30 and reflective sheets slots 31 can be seen. The corners of the base 6 on this side opposite to the side in contact with the column have indents 40 to allow the bases 6 to stacked on top of each other to optimise production and shipping. Figure 5 illustrates two plates 4a, 4b which form the column 3 of the solar thermal collector of the illustrated embodiment. The two plates 4a, 4b intersect using the lower column slot 53 and upper column slot 55 to form a column with a cross-shaped cross-section. The lower end of each of the plates 4a, 4b has two tabs, forming four distinct tabs 51a, 51b, 51c, 51d with which the column 3 is attached to the base. At least one of the tabs 51a, 51b, 51c, 51d is a different length, which corresponds to the length of the slots on the base, ensuring that the column can only be positioned in the correct orientation. The plates 4a, 4b contain two slots 52 approximately half-way along the height of the plates 4a, 4b and two slots 52 three-quarters along the height of plates 4a, 4b into which side tabs of the reflective sheet fit. The guides 5 along the outer side edges of the plates 4a, 4b are regularly spaced along each edge. The guides 5 along each edge of the plates 4a, 4b are at distinct heights compared to the other guides 5, in that the lowest indentation of the guide 5 starts at different heights along each edge. Along the path of the conduit, the first arm of the column 3 has the guide 5 starting at the lowest height, the second column 3 arm has the guide 5 starting at the second lowest height, the third column 3 arm has the guide 5 starting at the third lowest height and the fourth column 3 arm has the guide 5 starting at the highest height along the edge. This allows the conduit to gradually increase in height from the base as it is placed in the guides 5 of each arm of the column 3 as the coil is formed. The increase in the height of the conduit at each guide 5 of the column 3 is designed to position the conduit at the same height as a gap between adjacent portions of the conduit on the opposite side of the coil in any horizontal plane. Figure 6 illustrates the arrangement of the column 3, reflective sheets 7 and base 6 of the solar thermal collector. Each reflective sheet 7 is positioned between two adjacent column 3 arms using the tabs on the reflective sheets 7 in combination with the slots 52 in the column 3 and the reflective sheet slots 31 in the base 6. The guides 5 on the column 3 extend out past the reflective sheet 7 and are almost to the edge of the base 6. The clip 10 is positioned so that the conduit will enter through the inlet fitting and be placed on the guide 5 of the first column 3 arm with the lowest guide 5 starting position. The column 3 is arranged so that the diameter is largest at the base 6 and smallest at the top, forming a pyramid structure. Figures 7a and 7b illustrate a side view of a conduit 72, 2 coil of a solar thermal collector of the prior art and of the solar thermal collector of the present invention. Figure 7a shows the conduit 72 coil of the prior art, in isolation from the rest of the solar thermal collector. The spaces 71 between adjacent portions of the conduit 72 in the prior art coil 70, are in the same horizontal plane as a space 71 between adjacent portions of the conduit coil 70 on the opposite side of the coil 70. The conduit 72 of the prior art increases height at one section only of the coil 70, shown on the right-hand side of the coil 70. In other words, the coil passes around most of the column in one plane and then moves up to the next plane at the same point around the column. Figure 7b shows the conduit 2 coil of the present invention, in isolation from the rest of the solar thermal collector. The conduit coil of the present invention has spaces 71 between adjacent portions of the conduit 2 in the coil, as shown at the edges of the coil. However, the height of the conduit increases consistently and gradually over the entire coil as opposed to the conduit coil of the prior art 70. This results in the spaces 71 on a first side of the conduit 2 aligning with a portion of the conduit 2 on the opposite side of the coil in a horizontal plane. Therefore, there are no direct paths across the coil in the horizontal plane in which the solar radiation could enter and pass through the coil structure without hitting the conduit 2. Figure 8 illustrates a top view of a solar thermal collector of the present invention. The conduit 2 coil reduces in diameter as it increases in height above the base 6, resulting in the conduit 2 being able to absorb solar radiation from above along its entire length. The cap 15 of the solar thermal collector is transparent and the column 3 and reflective sheets 7 can be seen through the cap 15. The solar radiation entering through the cap 15 can be reflected off the reflective sheet 7 and directed towards the inner surfaces of the conduit 2 coil to absorb the radiation and heat the fluid inside. Figure 9 illustrates three different example configurations of the reflective sheets 7, which also show the tab 52a that interacts with the slots 52 in the plates of the collector and tab 31a that fits into reflective sheet slots 31 in the base of the collector. In each of the reflective sheets shown, A, B and C, a different pattern of non-reflective and reflective material is shown. In the first, A, a plurality of reflective dots are shown on a non-reflective background. In the second, B, a plurality of reflective stripes are shown, separated by non-reflective bands. In the third, C, the reflective sheet comprises a series of alternating non-reflective and reflective triangles. EXAMPLE The performance of a solar thermal collector according to the invention, as shown in Figures 1 and 2, was compared to the performance of the solar thermal collector discussed in WO2020 / 254822, as shown in the table below. The testing was carried out according to ISO 9806:2017. Prior art model (as shown in WO2020 / 254822) Present Invention (as shown in Figures 1 and 2)Optical efficiency (%)42.348.3Stagnation temperature (°C)6678 The data demonstrates that the solar thermal collector of the present invention has a higher optical efficiency compared to the solar thermal collector of the prior art. Further, the maximum temperature of a fluid in the conduit that can be achieved by the solar thermal collector (the stagnation temperature) is increased by over 10 °C compared to the solar thermal collector of the prior art. The solar thermal collector of the present invention demonstrates an increase in optical efficiency of over 14% compared to the collectors of the prior art. The improved optical efficiency is because of reduced optical losses i.e. less solar radiation escaping the solar thermal collector. The reduced optical losses are due to the improved arrangement of the conduit coil compared to collectors of the prior art and / or the use of the one or more reflective sheets positioned behind but not in direct contact with the conduit. The solar thermal collector of the present invention demonstrates an increase in the maximum fluid temperature of more than 15%. This increase in maximum fluid temperature is because of the reduced heat losses observed with the improved solar thermal collector. The reduced heat losses are due to at least the improved base with a honeycomb structure, improved housing to reduce air flow into the collector and the improved optical efficiency. Therefore, the data demonstrates that the improved design of the solar thermal collector of the present invention results in the increased conversion of solar energy into heat and reduces the amount of energy lost to ambient surroundings. Therefore, the current collector results in a more efficient heating of the fluid in the conduit compared to collectors of the prior art and results in an increased maximum temperature of the fluid in the conduit compared to the prior art. The new design also allows an easier assembly process from its flat-pack state to a fully assembled state.
Claims
1. A solar thermal collector adapted to be assembled from a flat pack configuration, comprising:a conduit configured to carry fluid and to absorb radiation; anda column configured to support the conduit, the column comprising guides for securing the conduit in place such that the conduit forms a coil,wherein the spacing of the guides means that adjacent portions of the conduit are not in contact with one another, and wherein over 80% of the space between adjacent portions of the conduit does not align with a space between adjacent portions of the conduit on the diametrically opposite side of the coil. 2. The solar thermal collector according to Claim 1, wherein the column comprises a plurality of plates, optionally wherein the guides are formed from a plurality of indentations along one or more edges of said plates. 3. The solar thermal collector according to Claim 2, wherein the column is formed from two intersecting plates, wherein the guides are formed from indentations along opposite edges of each plate such that the plates form a cross-shaped cross-section having indentations along the end of each arm thereof. 4. The solar thermal collector according to any one of Claims 1 to 3, further comprising one or more reflective sheets positioned within the coil and angled to direct radiation towards the conduit. 5. The solar thermal collector according to Claim 4, wherein the one or more reflective sheets comprise both reflective and non-reflective material on the side facing the conduit. 6. The solar thermal collector according to Claim 4 or 5, wherein the one or more reflective sheets are connected to the column. 7. The solar thermal collector according to Claim 6, wherein the column is formed from a plurality of plates and wherein a reflective sheet is connected to and extends between each of said plates. 8. The solar thermal collector according to any one of Claims 1 to 7, further comprising a base connected to the column, wherein the base comprises connecting means for holding the column in position. 9. The solar thermal collector according to Claim 8, wherein the connecting means comprises one or more slots in the base, into which one or more bottom portions of the column can be inserted. 10. The solar thermal collector according to Claim 9, wherein the one or more slots have lengths which correspond to the lengths of the bottom portions of the column, such that the column can only be connected to the base in the desired orientation. 11. The solar thermal collector according to any one of Claims 8 to 10, wherein the solar thermal collector further comprises one or more reflective sheets positioned within the coil and angled towards the conduit and wherein the base comprises secondary connecting means for holding the one or more reflective sheets in position. 12. The solar thermal collector according to any one of Claims 8 to 11, wherein the base is formed from a single piece of a polymeric material, optionally wherein the base further comprises a honeycomb structure on the side opposite that connected to the column. 13. The solar thermal collector according to any one of Claims 8 to 12, wherein the base further comprises one or more indents on the side opposite that connected to the column to allow stacking with other identical bases. 14. The solar thermal collector according to any one of Claims 8 to 13, wherein the base further comprises an aperture for a clip to anchor the conduit before it reaches the column. 15. The solar thermal collector according to any one of Claims 1 to 14, further comprising a housing that surrounds the conduit and the column. 16. The solar thermal collector according to Claim 15, wherein the solar thermal collector comprises a base that has one or more raised edges, seals and / or slots that connect to the housing, optionally wherein these extend around at least part of the perimeter of the base. 17. The solar thermal collector according to Claim 15 or 16, wherein the solar thermal collector comprises a base that has a raised hood portion at one or more corners thereof that connects to the housing. 18. The solar thermal collector according to any one of Claims 1 to 17, wherein the diameter of the base of the coil is greater than the diameter of the top of the coil. 19. A system comprising a plurality of solar thermal collectors according to any one of Claims 1 to 18. 20. A flat-pack kit for assembling a solar thermal collector according to any one of Claims 1 to 18 comprising a conduit and a column. 21. A method of constructing a solar thermal collector, comprising assembling the kit of Claim 20.