Patent Description:
The present invention relates to a heat transfer panel and a method.

Heat transfer panels are used in the installation of surface heating and cooling systems, of which underfloor heating systems are presently the most common example. Diffuser plates are commonly used for distribution of heat in dry construction floors (i.e. those without a concrete screed). Diffuser plates are typically made from aluminium or an alloy of aluminium and are pressed into a channel to accept a pipe flanked by wings which transfer heat into the floor. The diffuser plate can either sit into routed insulation or is fixed directly to the battens or joists of a floor. In all instances a covering is laid over the plates, e.g. a floor deck such as chipboard in an underfloor heating system.

A diffuser plate may have two pressed channels for pipes and be fixed to the top of battens or joists within a suspended floor. Insulation is laid loose below the diffuser plate. Diffuser plates are rigid and the pipe can only be inserted where a channel has been formed. This means that the pipe can only enter and leave the plate at the ends making it difficult to lay pipe around obstructions and maintain the pipe in a diffuser plate. The plates have a hard temper to provide more rigidity and are usually between <NUM> to <NUM> thick, although if the plates are not structural they can be as thin as <NUM> and bonded into insulation. Nevertheless, they are all very difficult to trim on site. Due to the difficulties of drawing aluminium into non-linear channels, diffuser plates are only used where there is a straight length of pipe, and any curves or bends in the pipe very rarely have a diffuser plate installed. Where there is no diffuser plate there is no significant contribution to the heat transfer. Depending on room size, curves and bends typically occupy <NUM>% of the room. In bathrooms where room area is smaller it can be greater than <NUM>%.

Conventionally pipe work is installed in straight runs with curves (where the pipe turns <NUM> degrees to travel back down the room) at the periphery of the room. In a suspended floor the pipe must pass through the joist. The pipe often crosses the joist in an area that can contravene building regulations (if the joists are not oversized). Joists can be notched between <NUM>% and <NUM>% of the joist length from the point of support. If the pipe work of a conventional system with diffuser plates were to pass through the joists in the correct place the plates would need to be trimmed where the pipe bends through the joist. As a result the unheated area would significantly increase from <NUM>% to <NUM>%. Alternative methods of putting heating into dry construction floors involve using a combination of straight and curve panels, laid such as to be able to install the pipe in a serpentine fashion (going up and down within a room). These products are usually supplied as "straights" and "curves", with a set of curves placed perpendicular to the straights. Having to use different products makes preparation of a bill-of-materials and consequent installation difficult. In non-rectangular rooms it is difficult to apply this method without significant trimming and repositioning of the curve panels.

<CIT> discloses a panel for underfloor heating systems as known in the art. The panel may comprise a support plate defining grooves to receive heating pipes. The support plate may be covered in an aluminium foil. The aluminium foil may extend over an arcuate portion of the grooves and have perforations defined therein such that the heating pipes can be pushed through the aluminium foil.

<CIT>, <CIT>, and <CIT> disclose other panels for underfloor heating systems as known in the art.

Although different heat transfer panels exist, they each have they own shortcomings. Accordingly, it is desired to provide an improved heat transfer panel.

According to a first aspect, there is provided a heat transfer panel according to claim <NUM>.

The first aspect recognizes that a problem with existing arrangements is that the fabrication of the heat transfer panels can be problematic and that the amount of conductive material which contacts the fluid conveying pipe can be less than desired which can lead to poorer heat transfer than is otherwise possible. Accordingly, a panel is provided. The panel may be a heat transfer panel. The heat transfer panel may comprise a substrate sheet or slab. The substrate may define or have at least one surface channel. The surface channel may be dimensioned or formed to receive, retain or hold a pipe. The panel may comprise a layer of conductive material. The layer of conductive material may overlie or be provided on the substrate. The conductive material may have fissures or perforations. The fissures may define or form a tessellated or repeating pattern. The fissures may facilitate or help the conductive material to be divided, separated or partitioned to enable the pipe to be inserted into the surface channel. In this way, the provision of the tessellated pattern makes the fabrication of the panel easier since having a repeated pattern of fissures helps to increase the likelihood that a fissure will be overlying a channel in which the pipe is to be inserted, thus avoiding the need to accurately align the fissures with the channel. In addition, the amount of conductive material which enters the channel is increased which increases contact with the fluid conveying pipe which leads to improved heat transfer.

The heat transfer panel may comprise an outer layer of conductive material overlying the adjacent layer of conductive material, the outer layer of conductive material having fissures which define a second tessellated pattern to facilitate dividing of the outer layer of conductive material to allow insertion of the flexible fluid-conveying pipe into the surface channels. Providing an outer layer enhances the probability that fissure lines will overlie a channel and helps to increase the amount of conductive material which enters the channel upon insertion of the pipe into the channel which enhances heat conduction between the pipe and the conductive material.

The heat transfer panel may comprise at least one intermediate layer of conductive material located between the adjacent layer of conductive material and the outer layer of conductive material, the at least one intermediate layer of conductive material having fissures which define a further tessellated pattern to facilitate dividing of the at least one intermediate layer of conductive material to allow insertion of the flexible fluid-conveying pipe into the surface channels. Hence, additional layers of conductive material may be provided with enhances the probability that fissure lines will overlie a channel and helps to increase the amount of conductive material which enters the channel upon insertion of the pipe into the channel which enhances heat conduction between the pipe and the conductive material.

The heat transfer panel may comprise a plurality of intermediate layers of conductive material located between the adjacent layer of conductive material and the outer layer of conductive material.

The panel may comprise an adhesive layer disposed between the substrate and the adjacent layer of conductive material to adhere the adjacent layer of conductive material to the substrate. Hence, the layer of conductive material may be adhered to the substrate. The adhesive layer may be disposed so that no adhesion occurs over the channels.

The adjacent layer of conductive material may define apertures to facilitate contact between the outer layer of conductive material and/or the intermediate layer(s) of conductive material and the adhesive layer to adhere the outer layer of conductive material and/or the intermediate layer(s) of conductive material to the substrate. Hence, the same adhesive layer may be used to adhere the conductive layers to the substrate.

Each of the at least one intermediate layer of conductive material may define apertures to facilitate contact between the outer layer of conductive material and the adhesive layer to adhere the outer layer of conductive material to the substrate.

The apertures may be located away from the fissures of that conductive layer. Hence, the sheet may be free to separate along the fissures.

Each tessellated pattern other than the second tessellated pattern may comprise a plurality of the apertures, that tessellated pattern defines a pattern width and the plurality of the apertures are positioned across that pattern width. Hence, the apertures may be contained within each tessellated pattern.

The plurality of the apertures may be positioned across the pattern width to match a spatial offset between the adjacent layer of conductive material, the at least one intermediate layer of conductive material and the outer layer of conductive material.

Each tessellated pattern other than the second tessellated pattern may comprise an elongate aperture having an elongate axis orientated along a direction of a spatial offset between the adjacent layer of conductive material, the at least one intermediate layer of conductive material and the outer layer of conductive material.

The adjacent layer of conductive material, the at least one intermediate layer of conductive material and/or the outer layer of conductive material may be positioned to spatially offset the first tessellated pattern, the further tessellated pattern and/or the second tessellated patterns. This again helps improve the probability of a fissure being present over the channel and increases the amount of conductive material which may enter the channel to improve conduction between the pipe and the conductive material.

The adjacent layer of conductive material, the at least one intermediate layer of conductive material and/or the outer layer of conductive material may be spatially offset to locate a corresponding edge of the first tessellated pattern, the further tessellated pattern and/or the second tessellated patterns to be parallel.

The adjacent tessellated pattern may define a pattern width and the at least one intermediate layer of conductive material and the outer layer of conductive material may be spatially offset to locate a corresponding edge of the further tessellated pattern and the second tessellated patterns within the pattern width.

The adjacent tessellated pattern may define a pattern width and the at least one intermediate layer of conductive material and the outer layer of conductive material may be spatially offset to locate a corresponding edge of the further tessellated pattern and the second tessellated patterns evenly spaced within the pattern width.

The adjacent, intermediate and/or outer layers of conductive material may be spatially offset such that a vertex of the first tessellated pattern is located towards a centre of the second and/or further tessellated patterns.

The second and/or further tessellated patterns may have a width which is no wider than the width of the surface channels.

The first, second and/or further tessellated patterns may be configured to at least partially line the surface channels with divided portions of a respective adjacent, outer and/or intermediate conductive layer on insertion of the flexible fluid-conveying pipe into the surface channels.

The first, second and/or further tessellated patterns may be configured to line the surface channels with divided portions of a respective at least one of the adjacent, outer and intermediate conductive layer to at least mid-way along side walls of the surface channels on insertion of the flexible fluid-conveying pipe into the surface channels.

The first, second and/or further tessellated patterns may be configured to line the surface channels with divided portions of a respective at least one of the adjacent, outer and intermediate conductive layers to a position where the flexible fluid-conveying pipe contacts the surface channels on insertion into the surface channels.

The first, second and/or further tessellated patterns may be configured to line the surface channels with divided portions of a respective at least one of the adjacent, outer and intermediate conductive layers to a position where a tangent to the flexible fluid-conveying pipe on insertion into the surface channels becomes vertical.

The fissure lines may define the first, second and/or further tessellated patterns as either a regular or irregular tessellated pattern.

The fissure lines may define the tessellated pattern as a tessellated polygon pattern.

The fissures may define the tessellated pattern as a tessellated regular polygon pattern.

The fissures may define the tessellated pattern as a hexagon, square and/or triangle pattern.

The tessellated pattern may extend across at least that area of the substrate which defines the surface channels.

The tessellated pattern may extend across all of the substrate.

The substrate may incorporate a multiplicity or plurality of gas spaces or voids.

The substrate may be formed from a cellular plastics material.

The substrate may be of a fibrous nature.

The surface channels may form a pattern comprising substantially parallel straight lines joined by curves.

The pattern may comprise two intersecting sets of substantially parallel straight lines.

The curves may be formed by rings which intercept both sets of lines.

The panel may comprise the flexible fluid conveying pipe.

According to a second aspect, there is provided a method according to claim <NUM>.

The method may comprise providing an outer layer of conductive material overlying the adjacent layer of conductive material and defining, with fissures in the outer layer of conductive material, a second tessellated pattern to facilitate dividing of the second layer of conductive material to allow insertion of the flexible fluid-conveying pipe into the surface channels.

The method may comprise providing at least one intermediate layer of conductive material located between the adjacent layer of conductive material and the outer layer of conductive material, and defining with fissures in the at least one intermediate layer of conductive material a further tessellated pattern to facilitate dividing of the at least one intermediate layer of conductive material to allow insertion of the flexible fluid-conveying pipe into the surface channels.

The method may comprise providing a plurality of intermediate layers of conductive material located between the adjacent layer of conductive material and the outer layer of conductive material.

The method may comprise disposing an adhesive layer between the substrate and the adjacent layer of conductive material to adhere the adjacent layer of conductive material to the substrate.

The method may comprise defining apertures in the adjacent layer of conductive material to facilitate contact between the outer layer of conductive material and/or the intermediate layer(s) of conductive material and the adhesive layer to adhere the outer layer of conductive material and/or the intermediate layer(s) of conductive material to the substrate.

The method may comprise defining apertures in each the at least one intermediate layer of conductive material to facilitate contact between the outer layer of conductive material and the adhesive layer to adhere the outer layer of conductive material to the substrate.

The method may comprise locating the apertures away from the fissures of that conductive layer.

Each tessellated pattern other than the second tessellated pattern may comprise a plurality of the apertures, that tessellated pattern defines a pattern width and the method may comprise positioning the plurality of the apertures across that pattern width.

The method may comprise positioning the plurality of the apertures across the pattern width to match a spatial offset between the adjacent layer of conductive material, the at least one intermediate layer of conductive material and/or the outer layer of conductive material.

The method may comprise positioning the adjacent layer of conductive material, the at least one intermediate layer of conductive material and/or outer layer of conductive material to spatially offset the first, second and/or further tessellated patterns.

The method may comprise spatially offsetting the adjacent layer of conductive material, the at least one intermediate layer of conductive material and/or the outer layer of conductive material to locate a corresponding edge of the first tessellated pattern, the further tessellated pattern and/or the second tessellated patterns to be parallel.

The adjacent tessellated pattern may define a pattern width and the method may comprise spatially offsetting the at least one intermediate layer of conductive material and the outer layer of conductive material to locate a corresponding edge of the further tessellated pattern and the second tessellated patterns within the pattern width.

The adjacent tessellated pattern may define a pattern width and the method may comprise spatially offsetting the at least one intermediate layer of conductive material and the outer layer of conductive material to locate a corresponding edge of the further tessellated pattern and the second tessellated patterns evenly spaced within the pattern width.

The method may comprise positioning the adjacent. intermediate and/or outer layers of conductive material to locate a vertex of the first tessellated pattern towards a centre of the second and/or further tessellated patterns.

The method may comprise dimensioning the first, second and/or further tessellated patterns to locate a fissure over the surface channels.

The method may comprise dimensioning the second and/or further tessellated patterns to have a width which is no wider than the width of the surface channels.

The method may comprise dimensioning the first, second and/or further tessellated patterns to at least partially line the surface channels with divided portions of a respective at least one of the adjacent, intermediate and/or outer conductive layer on insertion of the flexible fluid-conveying pipe into the surface channels.

The method may comprise dimensioning the first, second and/or further tessellated patterns to line the surface channels with divided portions of a respective at least one of the adjacent, intermediate and/or outer conductive layer to at least mid-way along side walls of the surface channels on insertion of the flexible fluid-conveying pipe into the surface channels.

The method may comprise dimensioning the first, second and/or further tessellated patterns to line the surface channels with divided portions of a respective at least one of the adjacent, intermediate and/or outer conductive layer to a position where the flexible fluid-conveying pipe contacts the surface channels on insertion into the surface channels.

The method may comprise dimensioning the first, second and/or further tessellated patterns to line the surface channels with divided portions of a respective at least one of the adjacent, intermediate and/or outer conductive layer to a position where a tangent to the flexible fluid-conveying pipe on insertion into the surface channels becomes vertical.

The method may comprise forming the fissures to define the first, second and/or further tessellated patterns as one of a regular and irregular tessellated pattern.

The method may comprise forming the fissures to define the tessellated pattern as a tessellated polygon pattern.

The method may comprise forming the fissures to define the tessellated pattern as a tessellated regular polygon pattern.

The method may comprise forming the fissures to define the tessellated pattern as a tessellated hexagon, square and/or triangle pattern.

The method may comprise extending the tessellated pattern across at least that area of the substrate which defines the surface channels.

The method may comprise extending the tessellated pattern across all of the substrate.

The method may comprise incorporating a multiplicity of gas spaces in the substrate.

The method may comprise forming the substrate from a cellular plastics material.

The method may comprise forming a pattern comprising substantially parallel straight lines joined by curves with the surface channels.

The method may comprise fitting the flexible fluid-conveying pipe in at least one of the surface channels.

Before discussing embodiments in any more detail, first an overview will be provided. Some embodiments provide a panel for use in an underfloor heating or cooling system, or the like. The panel has a substrate or slab layer into which recesses or channels are formed for holding typically a flexible pipe. The panel has one or more layers of a conductive material which are fixed to the surface of the substrate. The conductive layer is provided with a tessellated or tiled pattern of geometric shapes which are formed in that layer by lines of perforations or fissures in the conductive layer. When a pipe is to be installed into the panel, it is pushed against the layer of conductive material overlying the channel into which the pipe is to be located and the layer of conductive material separates, splits or divides along the fissure lines to enable the pipe to be fitted into the channel. Forming a tessellated pattern across the conductive layer helps to improve the likelihood that fissures are provided over the region of the channels which makes the panels easier to manufacture. The presence of the fissure lines helps to constrain how the layer of conductive material separates and the separate portions of the conductive layer on either side of the pipe are typically pushed by the pipe along the sidewalls of the channels to provide a conductive path between the pipe and the conductive material extending across the surface of the substrate. Providing one or more further layers of conductive material with a tessellated pattern also helps to improve the likelihood that fissures are provided over the region of the channels and helps to increase the amount of contact between the pipe and the conductive layers extending across the surface of the substrate to enhance heat transfer between the pipes and the surface of the substrate. In some embodiments, the conductive layer proximate the substrate has apertures to enable the adhesive bonding that conductive layer to the substrate to also bond the further layer(s) of conductive material also to the substrate using the same adhesive. As mentioned above, the provision of a tessellated pattern in the conductive material makes the manufacture of the heat transfer panel easier, since precise alignment of the fissures or perforations with the underlying channels is not required, and also helps to align the channels with more conductive material than would otherwise reliably be possible.

<FIG> is an exploded isometric view of a portion of a heat transfer panel <NUM> according to one embodiment. The heat transfer panel <NUM> has a support board or substrate <NUM> which is covered by a thinner heat conducting layer <NUM>. The substrate <NUM> is formed of a suitable rigid or slightly rigid flexible structural material. The substrate <NUM> will normally act as a thermally insulating layer. In such cases, the substrate <NUM> will typically incorporate a plurality of spaces filled with air, argon or another suitable gas in order to reduce the overall weight of the substrate as well as providing improved heat insulation properties. Suitable materials might therefore include foamed plastics and materials of a fibrous nature. In some applications, the substrate <NUM> may be required to provide enhanced sound insulation, in which case the substrate will be made from a solid dense board.

Typically, the substrate <NUM> is formed with an array of interconnecting channels <NUM> into which a flexible fluid conducting pipe (not shown) can be inserted. In the orientation shown, the channels <NUM> open through an upper surface <NUM> of the substrate <NUM> or, in other words, the upper surface <NUM> of the substrate <NUM> defines the channels <NUM>. It will be appreciated that the substrate <NUM> can be used in any orientation. Although the channels <NUM> are shown having a U-shaped cross-section, the channels <NUM> can have any suitable cross-section which enables pipes (not shown) to be introduced and preferably retained in place by the channel <NUM>. For example, the channels <NUM> may be formed having a slight horseshoe cross-section with opposing inwardly extending lips in order to narrow the channel at its opening to help retain the pipe in place.

<FIG> shows a layout for the channels <NUM>. It will be appreciated that this is only by way of illustration and other channel arrangements are possible. In the illustrated configuration, the channel pattern includes two intersecting sets of straight channels as well as interconnecting circular channels. The straight channels are parallel and equally spaced and two of the sets of straight channels are mutually perpendicular to form a grid of squares, each of which contains a circular channel intersecting the four sides of the square at their midpoints. At the sides of the substrate <NUM>, the circular channels are bisected by the edges of the panel leaving only half-circle channels with quarter circle channels remaining at the four corners.

Returning now to <FIG>, the heat conducting layer <NUM> is formed from one or more sheets of a bendable material such as aluminium, copper or other metal foil or conductive material (for example graphene) which can be much thinner than conventional diffuser plates, typically only <NUM> microns thick. The heat conducting layer <NUM> is bonded to the surface <NUM> in any suitable manner to form a substantially planar layer which spans the channels <NUM> and completely covers them prior to use. Although the heat conducting layer <NUM> can comprise a single sheet, the heat conducting layer <NUM> preferably comprises at least two layers, a lower (adjacent) layer <NUM> and an upper (outer) layer <NUM> which are superimposed or overlie each other with the lower layer <NUM> being proximate the substrate <NUM> and the upper layer <NUM> being distal the substrate <NUM>. In the arrangement shown in <FIG>, an adhesive is applied to the surface <NUM> and the lower layer <NUM> is bonded to the surface <NUM> by the adhesive. Apertures <NUM> in the lower layer <NUM> expose the adhesive on the surface <NUM> to the upper layer <NUM> which also then bonds to the adhesive on the surface <NUM> through the apertures <NUM> to directly bond the upper layer <NUM> to the substrate <NUM>.

The lower layer <NUM> and upper layer <NUM> are provided with fissure lines <NUM>, <NUM> which define a tessellated pattern across the lower layer <NUM> and upper layer <NUM> respectively. In this example, the fissures <NUM>, <NUM> define a regular hexagonal pattern. However, it will be appreciated that other tessellated patterns are possible. Also, in this example the fissure lines <NUM>, <NUM> extend across the whole surface of the lower layer <NUM> and upper layer <NUM>, but it will be appreciated that this need not be the case and that the tessellated pattern may be provided across just a portion of the lower layer <NUM> and upper layer <NUM> to overlie the channels <NUM>. The size of the hexagons <NUM>, <NUM> is dimensioned in relation to the size of the channels <NUM>. In particular, the hexagons <NUM>, <NUM> are dimensioned to be smaller than the width of the channels <NUM> so that a hexagon <NUM>, <NUM> is unlikely to span the entire width of the channels <NUM> and thus resist the layers being separated along the fissure lines <NUM>, <NUM>. For example, for a <NUM> width channel, a <NUM> hexagon is effective whilst for a <NUM> width channel, a <NUM> hexagon is used.

<FIG> shows the positional relationship of the lower layer <NUM> with respect to the upper layer <NUM>. The hexagons <NUM> of the lower layer <NUM> and the hexagons <NUM> of the upper layer <NUM> are spatially offset. In particular, a vertex <NUM> formed by the fissure lines <NUM> of three adjacent hexagons <NUM> is positioned to overlie the centre of a hexagon <NUM>. This staggered alignment helps to provide at least some conductive material on both sides of the channel as a pipe is placed into a channel <NUM>, as will be described in more detail below. Although in this embodiment the hexagons <NUM>, <NUM> are spatially offset in the two major axes across the surface of the substrate <NUM>, this need not be the case and they may instead only be spatially offset in one of the major axes, as will be described in more detail below.

As can be seen in <FIG> and <FIG> (in which a portion of the upper layer <NUM> has been removed to show a portion of the lower layer <NUM>), as the pipe <NUM> is inserted into the channel <NUM>, the upper layer <NUM> splits along the fissure lines <NUM> and portions of the hexagons <NUM> line the sidewalls of the channel <NUM>. Likewise, the fissure lines <NUM> of the lower layer <NUM> split and hexagons <NUM> also line the sidewalls of the channel <NUM>. This helps to provide a conductive path from both sides of the pipe <NUM> through the portions of the lower layer <NUM> and upper layer <NUM> lining the sidewalls of the channels <NUM> to facilitate heat conduction between lower layer <NUM> and upper layer <NUM> extending across the surface <NUM> and the fluid flowing through the pipe <NUM>. In other words, due to the path of the fissure lines <NUM>, <NUM>, the lower layer <NUM> and upper layer <NUM> form flaps on opposite sides of the channel <NUM> which are deflected inwards as the pipe <NUM> is inserted to become sandwiched between the pipe <NUM> and the walls of the channel <NUM>. By using two or more layers <NUM>, <NUM>, the flaps form a substantially continuous lining along each side of the channel <NUM> and can extend to the bottom of the channel <NUM>, which would not be achieved using a single layer. For example, if the fissures extended only straight down the centre of a channel <NUM>, there would be very little, if any, contact with the pipe <NUM>. Taking a <NUM> pipe <NUM> as an example, the flap in these circumstances would be <NUM> wide which, when pushed into the channel <NUM>, would only meet pipe at the point where the pipe <NUM> first touches the substrate <NUM><NUM> from the surface. However, by having fissures <NUM>, <NUM> which do not extend straight down the centre of a channel <NUM> and which are offset, then the flap can be up to <NUM> wide and so extend further into the channel <NUM>.

<FIG> illustrates schematically a portion of an arrangement of heat conducting layer 35A formed from multiple sheets (in this arrangement, <NUM> sheets or plies of <NUM> or <NUM> microns thickness with the apertures omitted to improve clarity) of a bendable material such as aluminium, copper or other metal foil or conductive material (for example graphene) which can be much thinner than conventional diffuser plates, typically only <NUM> or <NUM> microns thick in total. <FIG> illustrates schematically the arrangement of the heat conducting layer 35A in relation to the substrate <NUM>. The heat conducting layer 35A is bonded to the surface <NUM> in any suitable manner to form a substantially planar layer which spans the channels <NUM> and completely covers them prior to use.

The heat conducting layer 35A is formed of four layers, a lower (adjacent) layer 30A and an upper (outer) layer 60A which are superimposed or overlie each other with the lower layer 30A being proximate the substrate <NUM> and the upper layer <NUM> being distal the substrate <NUM>. Between the lower layer 30A and the upper layer 60A are a first intermediate layer 31A overlying the lower layer 30A and a second intermediate layer 33A overlying the first intermediate layer 31A.

As will be described in more detail below, similar to the arrangement shown in <FIG>, an adhesive is applied to the surface <NUM> and the lower layer 30A is bonded to the surface <NUM> by the adhesive. Apertures in the lower layer 30A expose the adhesive on the surface <NUM> to first intermediate layer 31A. Apertures in the first intermediate layer 31A expose the adhesive on the surface <NUM> to the second intermediate layer 33A. Apertures in the second intermediate layer 33A expose the adhesive on the surface <NUM> to the upper layer 60A.

The lower layer 30A, the first intermediate layer 31A, the second intermediate layer 33A and the upper layer 60A are provided with fissure lines which define a tessellated pattern across the lower layer 30A, the first intermediate layer 31A, the second intermediate layer 33A and the upper layer 60A respectively. In this example, the fissures define a regular hexagonal pattern. However, it will be appreciated that other tessellated patterns are possible. Also, in this example the fissure lines extend across the whole surface of the lower layer 30A, the first intermediate layer 31A, the second intermediate layer 33A and the upper layer 60A, but it will be appreciated that this need not be the case and that the tessellated pattern may be provided across just a portion of the lower layer 30A, the first intermediate layer 31A, the second intermediate layer 33A and the upper layer 60A to overlie the channels <NUM>. The size of the hexagons is dimensioned in relation to the size of the channels <NUM>. In particular, the hexagons are dimensioned to be smaller than the width of the channels <NUM> so that a hexagon is unlikely to span the entire width of the channels <NUM> and thus resist the layers being separated along the fissure lines. For example, for a <NUM> width channel, a <NUM> hexagon is effective whilst for a <NUM> width channel, a <NUM> hexagon is used.

As can be seen in <FIG> which shows the positional relationship of the lower layer 30A with respect to the first intermediate layer 31A, the second intermediate layer 33A and the upper layer 60A. The hexagons 39A of the lower layer 30A, the hexagons 37A of the first intermediate layer 31A, the hexagons 38A of the second intermediate layer 33A and the hexagons 69A of the upper layer <NUM> are spatially offset. In particular, a corresponding edge of each hexagon is arranged to be parallel with respect to each other with the overlying hexagons 37A, 38A, 69A being evenly distributed across the width of the hexagon 39A. In other words, the hexagons are spaced apart equally along one major axis of the surface <NUM>. For example, if the width of the hexagons is a distance D and the total number of layers is N, then each overlaid hexagon is offset from the underlying hexagon by D/N. For the <NUM> layer arrangement shown in <FIG>, each hexagon is offset by D/<NUM>. Typically, the offset is arranged to be parallel to the majority direction of the channels <NUM>.

This staggered alignment helps to provide at least some conductive material on both sides of the channel <NUM> as a pipe is placed into a channel <NUM>, as will be described in more detail below. Although in this embodiment the hexagons 39A, 37A, 38A, 69A are spatially offset in one major axes across the surface of the substrate <NUM>, this need not be the case and they may instead be spatially offset in two of the major axes in a similar manner to that described above.

As can be seen in <FIG> (in which a portion of the upper layer 60A, the first intermediate layer 31A and the second intermediate layer 33A has been removed to show a portion of the lower layer 30A), as the pipe <NUM> is inserted into the channel <NUM>, the upper layer 60A splits along the fissure lines and portions of the hexagons 69A line the sidewalls of the channel <NUM>. Likewise, the fissure lines of the lower layer 30A split and portions of the hexagons 39A also line the sidewalls of the channel <NUM>. Similarly, the fissure lines of the first intermediate layer 31A and the second intermediate layer 37A split and portions of the hexagons 38A also line the sidewalls of the channel <NUM>. This helps to provide a conductive path from both sides of the pipe <NUM> through the portions of the lower layer 30A, the first intermediate layer 31A, the second intermediate layer 33A and the upper layer 60A lining the sidewalls of the channels <NUM> to facilitate heat conduction between lower layer 30A and upper layer 60A extending across the surface <NUM> and the fluid flowing through the pipe <NUM>. In other words, due to the path of the fissure lines, the lower layer 30A, the first intermediate layer 31A, the second intermediate layer 33A and the upper layer 60A form flaps on opposite sides of the channel <NUM> which are deflected inwards as the pipe <NUM> is inserted to become sandwiched between the pipe <NUM> and the walls of the channel <NUM>. By using four or more layers the flaps form a substantially continuous lining along each side of the channel <NUM> and can extend to the bottom of the channel <NUM>, which would not be achieved using a single layer. For example, if the fissures extended only straight down the centre of a channel <NUM>, there would be very little, if any, contact with the pipe <NUM>. Taking a <NUM> pipe <NUM> as an example, the flap in these circumstances would be <NUM> wide which, when pushed into the channel <NUM>, would only meet pipe at the point where the pipe <NUM> first touches the substrate <NUM><NUM> from the surface. However, by having fissures which do not extend straight down the centre of a channel <NUM> and which are offset, then the flap can be up to <NUM> wide and so extend further into the channel <NUM>.

As mentioned above, embodiments utilise apertures which facilitate gluing of layers to the substrate <NUM>. Depending on the production process, <NUM> different configurations are envisaged which are: larger apertures, smaller apertures and lozenge or elongate apertures. It is preferable if the apertures are formed by perforation rather than by punching. As such, smaller pairs of apertures may be suitable. If punching is required then larger apertures are more suitable as are elongate apertures. However, it is preferable to reduce the amount of material removed as this affects the thermal performance of the heat transfer panel.

The aperture layout is typically common for each layer which contains such apertures (typically all layers except the outer layer). When there are M layers that contain apertures, then those layers are arranged to have M sets of spatially offset apertures, typically evenly spaced across the width of the tessellated shape.

For example, <FIG> illustrates an arrangement of the apertures for the lower layer 30A, the first intermediate layer 31A and the second intermediate layer 33A. Because there are four layers in total, three pairs of apertures 33B, 33C, 33D are provided, each spaced D/<NUM> apart. In other words, the first pair of apertures 33B are located at <NUM>% of the width of the hexagon, the second pair of apertures 33C are located at <NUM>% of the width of the hexagon and the third pair of apertures 33D are located at <NUM>% of the width of the hexagon. As each layer is applied and offset, the glue from the layers below will still be exposed to the overlying layers. In particular, the pair of apertures 33B provide adhesion for the first intermediate layer 31A, the pair of apertures 33C provide adhesion for the second intermediate layer 33A and the pair of apertures 33D provide adhesion for the upper layer 60A.

In another embodiment, rather than using individual apertures, instead a single larger aperture 33E may be used as illustrated in <FIG>. The aperture 33E is elongate or lozenge shaped and although its length is fixed to extend between <NUM>% and <NUM>% of the width of the hexagon (for a four layer arrangement), the width can be made a thin as possible. The aperture 33E may also be punched or preferably perforated.

To apply the conductive layers, the four layers could be interwound with the offset prior to being applied to the substrate <NUM>. Equally, they could be applied individually but at the same time. The conductive layers could also be perforated as it is applied. Some caution is needed as the individual layers will be difficult to roll as glue will be exposed to the rollers through the apertures.

As show in <FIG> which shows an arrangement for <NUM> to <NUM> pipes (<FIG>) and an arrangement for <NUM> to <NUM> pipes (<FIG>), there is a spatial offset in the conductive layers and they need to be applied in a certain way. For the avoidance of doubt, as can be seen, the layers 30A, 31A, 33A are identical, but spatially offset. To get the offset, either different rolls are needed (<NUM> rolls per product) with the offset put into the pattern or, to use the same rolls, the substrate <NUM> would have to be turned <NUM>° (so the straight channel is <NUM>° to the direction of travel) when fed through the gluing machine, this way the conductive layers can be offset when it is set up but be the same. One approach for achieving the offset is to place holes down the side of the conductive layers rolls to provide an 'index' and the conductive layers are fed together on a roll with 'teeth' at the ends much like a dot matrix printer.

The heat transfer panel <NUM> can easily be cut into smaller sections for use in any particular application. An important feature of the present heat transfer panel <NUM> is the ability to form <NUM> degree bends at opposite ends of two straight runs of pipe whilst still maintaining efficient thermal contact with the heat-conductive layer <NUM>. This is achieved by running the pipe <NUM> around one half of a circle <NUM>‴ between two parallel straight sections <NUM>' or <NUM>". Thus, as shown in <FIG> for example, sections S of the panel <NUM> can be mounted between joists J. The pipe <NUM> can be routed entirely within the sections S except when crossing joists J, where the pipe <NUM> exits from the edges via selected part circles <NUM>‴ or appropriate straight sections <NUM>' and <NUM>".

<FIG> also shows how the panels <NUM> allow the pipe <NUM> to leave the panel <NUM> and pass through a joist J at any convenient position enabling the installer to comply with building regulations without trimming or leaving panels <NUM> out, thereby reducing the heat transfer capability of the system.

<FIG> further demonstrates how the pipe <NUM> can easily be routed around an obstacle X.

The pipe can be used to carry either warm or cool water or any other suitable fluid. The contact between the pipe and the conductive layer enables heat to be transferred to or from the overlying structure (floor, ceiling etc.) either in a heating system where warm water is circulated through the pipes or for heat to be extracted from the structure in a cooling system where cool water is circulated through the pipes.

The heat transfer panel has many advantages over conventional products. Since the use of this type of diffuser creates a heat transfer panel that is universal (no "straights" and "curves") a single product can be used for an entire floor. Therefore, the quantities needed are very easy to calculate from the room area. Design and installation are also greatly simplified for smaller rooms with obstacles. The panel allows pipe to be installed in any direction so that the pipe can be run around obstacles. Different panels are not needed, nor the manipulation or trimming of panels. Importantly, the panel will maintain heat transfer in this area whereas conventional diffuser plate systems will not. Non-rectangular rooms with straights and curves are also greatly simplified. The panel is installed and trimmed in the same way as a normal insulation or flooring product. Only a simple design is required to show where the pipe work may go.

As the pipe inside the heat transfer panel is consistently in contact with an adjacent area of the conductive material via the flaps created when the pipe is pushed in, there is efficient heat transfer in all areas. With curves or bends in conventional diffuser plate systems this is not the case and there is a significant reduction in heat output from these areas. Indeed, in terms of heat performance, for the same conductive layer thickness, testing has shown that the embodiments provide a <NUM>% higher output than slitting the conductive layers along the centre line. Although a panel with fully lined channels has a <NUM>% higher output than the embodiments, the embodiments provide a higher heat output around the curves compared to slitting (<NUM>% higher) or unfoiled (<NUM>% higher). Therefore, across a system the embodiment performs better than fully lined aluminium (in the straights and slit/no aluminium around the curves). Furthermore, it is expected that compared to rigid diffusers, the embodiments will perform better due to better contact around the curves.

In summary, some embodiments allow much greater conductive layer(s) contact with the pipe in straights compared to a regular 'slit' aluminium layer. The same conductive layer(s) can be applied to any router pattern with the same result. The product should be cheaper to make than systems where the channel is fully lined with foil, or those that use a diffuser plate. The product is easy to cut and trim. The conductive layer(s) break easily and consistently. The product provides a high system output (for comparable thickness of aluminium) due to the even distribution of heat over straight and curved (loop) sections (where the latter is extremely difficult to apply a diffuser due to its shape).

Claim 1:
A heat transfer panel (<NUM>), comprising:
a substrate (<NUM>) defining an array of interconnecting surface channels (<NUM>) dimensioned to receive a flexible fluid-conveying pipe; and
an adjacent layer (<NUM>) of conductive material overlying said substrate and having fissures which define a first tessellated pattern to facilitate dividing of said adjacent layer of conductive material to allow insertion of said flexible fluid-conveying pipe into said surface channels, wherein said first tessellated pattern has a width which is no wider than a width of said surface channels.