GB2589105A - A thermal insulation and diffusion floor panel for an underfloor heating or cooling system - Google Patents

Abstract

The floor panel comprises thermally insulating board 1 having upper and lower surfaces 2,3 and a groove 4 formed in the upper surface. The panel also includes first and second strips of flexible thermally conductive foil 8, ideally aluminium foil, that are located on opposite sides of the groove. Each strip extends out over the groove such that one of the strips overlaps the other. When a heating element, e.g. a pipe 10, is located in the groove the pipe pushes the edges of the strips overlying the groove against walls of the groove so that the strips conform to the periphery of the pipe. The panel ideally has two or more parallel spaced grooves wherein the strip located between any two adjacent grooves has edges that overlap the entire width of each groove. The panel may include an upper protective layer 11 that is thermally conductive and a lower protective layer 11 that is thermally insulating. An associated method of manufacturing and underfloor heating system are also claimed. A panel having a different arrangement of foil (figures 4-6) and associated method and underfloor system are also claimed.

Description

A Thermal Insulation And Diffusion Floor Panel For An Underfloor Heating or Cooling System [1] The present invention relates to an underfloor heating thermal insulation and diffusion panel, for use in underfloor space heating or cooling, in new and existing buildings.

Prior Art

[2] Underfloor heating and cooling systems are known for space temperature control of residential and other buildings. Radiant systems provide: higher thermal comfort in comparison to convective space heating and cooling systems, energy saving and better room space utilization. In such systems thermal energy is delivered to or drawn from panels laid in the floor via an elongate heating element. The heating element is commonly a flexible pipe containing a working fluid, usually water. The water is driven by a pump to circulate through the pipe embedded in at least one and usually many panels in the floor. The water is either heated or cooled by a heat engine, in the case of heating usually a boiler (or furnace) but sometimes devices such as a heat pump or solar panels. For cooling a refrigerator or other heat pump may be used. The panels are laid onto a substrate, often concrete or wooden planks. The substrate will either be suspended over an airgap in communication with external atmosphere or an underlying building story/room or be in thermal contact with the ground. There is therefore unwanted heat transfer between the heating element and the substrate.

[003] For the sake of brevity the system will generally be described as a heating system but it should be understood that cooling is to be encompassed by the system and at least some heating systems may also be operated as cooling systems as desired.

[004J The heating element may be laid in any of a number of patterns, most commonly a coil or a zigzag pattern. In the latter case a length of heating element is laid to span usually, several floor panels before being turned so that a second length crosses the panels again parallel to and spaced from the first length. To minimise the labour in laying the heating element and the length of heating element required it is desirable to maximise the space between each length. However, this results in undesirable cold regions between hot regions immediately overlying the heating element.

[005J To meet the increasing demand for energy saving, methods have been proposed to, in the case of heating, minimise heat losses to the substrate or conversely heat gain from the substrate where the system is used for cooling, thereby maximising the system efficiency. The panel is installed onto an underlying substrate, usually a concrete or wooden substrate. The panel is fabricated from a thermally insulating material, commonly a foamed material to minimise heat transfer with the substrate. An overlying flooring layer is installed, commonly tiles of ceramic or stone, flooring planks of wood, laminate, concrete, fabrics (carpet) and other materials.

[006J Each of US4326366, EP0075143, EP0142497, US4865120, US5078203, US5579996, US6009612, W00237032, GB2490475, US9404665 propose an underfloor heating panel. Each discloses a panel with a planar upper surface. At least one groove is formed in the upper surface to receive a pipe arranged to convey heated or cooled water. A highly conductive metal sheet is bonded to the upper surface and is shaped to extend into the groove to make intimate thermal contact with the pipe providing a heat dispersion layer. Thus the conduction of thermal energy from the pipe to diffuse the heat across the upper surface is facilitated. If the pipe is conveying cold water the energy is conducted from the sheet on the upper surface of the panel, to the pipe.

[007] The metal sheet is formed with channels corresponding to the grooves before bonding to the panel. To facilitate handling before bonding to the panel the metal sheet must be of a gauge greater than is necessary for efficient thermal transfer, ie in excess of 0.15mm gauge. Furthermore, on insertion of the pipe into the sheet lined grooves airgaps form between the pipe and inflexible sheet which inhibit heat transfer. . [006] US 5579996 & US 6152377 propose filling the gaps between the heating tubes and metal plate using a compliant thermally conductive filler material, this adds to the system installation steps and materials and is therefore undesirably expensive.

[009] US 6,533 185 proposed attaching a metal foil on top of the grooved board, spanning the grooves, and then cutting the metal foil along the groove to form two edge regions or flaps of the metal foil which are then bent into the groove. The heating element is cylindrical, usually a hollow fluid carrying pipe. The maximum depth and width of the groove must correspond to at least the diameter of the pipe.

Accordingly flaps, if of uniform size, cannot be more than half the diameter of the heating element and therefore can extend to no more than half the depth of the groove. The groove conventionally has parallel side walls and an arcuate bottom to conform to the cylindrical heating element, at the bottom of the groove only. The result is that there is little if any direct contact between the flaps and the heating element.

Law/ However, the parts of the metal foil cannot extend more than half way into the groove, and consequently thermal contact between the heating conduit, in the groove, and the metal foil is poor.

[onj The objects of the present invention are to provide a floor panel that is: easy and economical to produce, minimises heat transfer to an underlying substrate, achieves excellent thermal conductance between the embedded thermal element and a heat dispersion layer, requires minimal material for the heat dispersion layer, minimal fabrication process steps, is simple to install, reliable and durable in operation.

Summary of Invention

First Aspect Accordingly a first aspect of the present invention provides a floor panel for use in an underfloor heating comprising a board formed of a thermal insulating material having an upper surface and lower surface; a groove formed in the upper surface so that the upper surface to either side of the groove forms a land, said groove dimensioned to closely receive a heating element; a pair of strips of flexible thermally conductive foil; a first of said foil strips attached to the land to one side of the groove and the second of said strips attached to the land to the other side of said groove, characterised in that each strip overlies or underlies the other strip at least where each overlies the groove, such that when a heating element is pressed against the edges of the strips overlying the groove the edges are pressed down into the groove to closely conform to the periphery of the heating element.

[13] The strips may overlap more than the width of the groove, however it is preferred that the first and second strips overlap substantially by the width of the groove this enables a large area of contact between the foil pressed into the groove and the heating element and obviates the step of cutting the foil overlying the groove.

[14] Preferably the groove has an arcuate, concave base and upstanding side walls extending to the upper surface. The side walls may be parallel to facilitate folding the foil edges into the groove. Preferably the groove is dimensioned to provide an interference fit with a standard sized heating element and the foil. By this means the heating element is retained in the groove and the foil is pressed into intimate contact with the heating element to maximise heat conductance. The foil will conveniently be an aluminium foil. Preferably each floor panel will include more than one groove, more preferably four grooves. Where there is more than one groove the strips attached to the land are arranged to have edges overlapping both adjacent grooves.

[015J Preferably the panel is moulded from a resiliently deformable foamed material having an elasticity selected to facilitate insertion and capture of the heating element into the interference fit groove.

1016J A layer of protective material may be secured to the strips of metal foil overlying the land. A protective material may also be secured to the lower surface.

Second Aspect [017J According to a second aspect of the present invention there is provided a method of manufacturing a floor panel comprising: shaping a board of thermally insulating material to have an upper surface and a lower surface; forming a groove in the upper surface so that the upper surface to each side of the groove forms a land; securing a first strip of thermally conductive foil to the land to one side of the groove so that an edge of the foil overlaps substantially the whole of the groove; securing a second strip of thermally conductive foil to the land on the other side of the groove so that the edge of the second strip overlaps the groove and the overlapping portion of the first strip.

[0181 On application of the foil the foil is substantially flat and undeformed so that deformation of the foil into the groove in use in constructing underfloor heating shapes the foil and causes it to conform to the cross section of the groove and heating element.

[19] The groove may be sized and shaped so that when the panel is used with a standard sized heating element the groove together with the foil form an interference fit to grip the heating element and press the foil into intimate contact with the heating element.

[20] It is preferable to form the panel with more than one groove, more preferably with four grooves.

[21] Preferably the board is moulded from a resiliently deformable foamed material having an elasticity selected to facilitate insertion and capture of the heating element into the interference fit groove.

[022.1 The method may include the step of securing a reinforcing layer over the foil strip overlying the land. The method may include the step of securing a reinforcing layer under the lower surface of the panel.

Third Aspect [023.1 According to a third aspect of the present invention there is provided a floor panel made of a board of thermally insulating material having an upper surface and lower surface; a groove formed in the upper surface dimensioned to closely receive a heating element so that the upper surface to each side of the groove forms a land; a strip of flexible thermally conductive foil attached to the land to each side of the groove and extending into the groove to conform to the cross sectional shape of the groove so that in use, when a standard heating element is pressed into the groove the heating element is in intimate contact with the foil lining the groove.

[0241 Preferably the groove is sized so that in cooperation with the foil it forms an interference fit between the groove, the foil and the heating element. Thus in use heating element is gripped by the opposing sidewalls of the groove and the foil will be pressed into intimate contact with the heating element.

[0251 Preferably the panel will have more than one groove, more preferably four grooves.

Where there is more than one groove a corresponding number of foils will be applied to the upper surface of the panel. Preferably each foil will be sized and located with respect to the groove such that when the foil has been deformed to line the groove the edge of the foil remote from the groove will substantially meet with the edge of the foil strip lining an adjacent groove.

[26] The panel may have a protective reinforcing layer secured to the foil overlying the land. A reinforcing layer may underlie the lower surface.

Fourth Aspect [27] According to a fourth aspect of the present invention there is provided a method of manufacturing a floor panel comprising the steps of forming a board of a thermally insulating material to have a lower surface and an upper surface; forming a groove in the upper surface sized and shaped to receive a heating element; applying a foil strip to the upper surface so that the strip wholly overlies the groove and at least part of each adjacent land; applying a press to the foil overlying the groove so that the foil is pressed down into the groove and conforms to the sides and bottom of the groove in order to line the groove.

1028.1 Preferably the strip of foil is a metal foil, more preferably an aluminium foil and is initially substantially flat and un-deformed prior to the application of the press. The press is preferably an elongate rod sized and shaped to complement the cross section of the groove and foil. The press will preferably extend along the entire length of the groove and be operated to press into the groove parallel to the upper surface in order to avoid tearing the groove. At the time the press is applied to the foil overlying the groove the foil overlying the land is not fixed to the land. This allows the foil to slide across the land into the groove. By appropriate sizing of the width of the foil strip it can be arranged that the final position of the edge of the foil covers substantially the whole of the land. Subsequent to applying the press the press is removed.

[029J In the preferred case where the panel includes multiple grooves, most preferably four grooves, the strip is dimensioned and positioned so that the edges of adjacent strips overlying the land are substantially adjacent subsequent to the application of

ID

the press. In this case the method may involve applying each required strip to the upper surface of the panel first and subsequently simultaneously applying presses corresponding to the number of grooves, to each strip.

[030J The method includes a step of securing the foil strip to each land adjacent the groove.

Fifth aspect [031] According to a fifth aspect of the present invention there is provided an underfloor heating system comprising a floor panel and a heating element; said floor panel made of a board of a thermal insulating material having an upper surface and lower surface; a groove formed in the upper surface so that the upper surface to each side of the groove forms a land, a pair of strips of flexible thermally conductive foil; a first of said foil strips attached to the upper surface to one side of the groove and the second of said strips attached to the upper surface to the other side of said groove, edge regions of each said strip extending more than half the width of the groove into the groove to line the walls of each groove; a heating element pressed into the groove to engage the foil and the groove and retained by an interference fit between the groove and the heating element.

Sixth Aspect [032J According to a sixth aspect of the present invention there is provided an underfloor heating system comprising a floor panel and a heating element; said floor panel made of a thermal insulating material having an upper surface and lower surface; a groove formed in the upper surface so that the upper surface to each side of the groove forms a land; a strip of thermally conductive foil attached to each land and extending into the groove to conform to the cross section of groove; and a heating element pressed into the groove and retained by an interference fit between the heating element, the foil and the groove whereby the foil is pressed into intimate contact with the heating element.

Brief Description of Drawings

[033J Embodiments of a floor panel and am underfloor heating system using the floor panel will now be described, by way of example only, with reference to the accompanying figures, in which: Figure. 1 is an end elevation of a board used in fabrication of the floor panel; Figure 2 is an end elevation of a floor panel according to a first embodiment; Figure 3 is an end elevation of an underfloor heating system using the panel of the first embodiment; Figure 4 is an end elevation of a floor panel and foils during a stage in fabrication of a second embodiment of the floor panel; Figure 5 is an end elevation of the floor panel and foils during another stage in the fabrication of the second embodiment; Figure 6 is an end elevation of an underfloor heating system using the panel of the second embodiment; and Figure 7 is a SW isometric view of an underfloor heating system according to the first embodiment with enlarged details views.

Detailed Description

[34] The floor panel illustrated in figures 1-3 and 7 is fabricated from a board 1 made of a compressible or elastic thermal insulating material as for example, but not limited to: [35] XPS foam, EPS foam, PU foam, phenolic foam or Mineral Wool. The panel illustrated is 1200mm long 247 mm wide and 22mm deep and cuboid in shape. The board 1 has a planar lower surface 2 and an opposing planar upper surface 3, elongate sides and elongate ends forming a generally planar cuboid structure. Four similar laterally spaced straight grooves 4 extend from end to end of the board 1. Each groove 4 is similar and has a pair of opposing parallel side walls 5 and an arcuate bottom 6. The groove may be formed by cutting a cuboid board but is more preferably formed by moulding or extruding the board. The upper surface to each side of each groove forms a land 7.

[36] An aluminium conductive flexible foil strip is 8 is secured to the land 7 so that an edge region forms a flap 9 extending to overly the groove 4. In the case of the lands adjacent to the longitudinal edges of the board the strips 8 end at the edge of the board. The strips 8 lying one lands between grooves have each edge regions overlapping the adjacent groove end the flap of an adjacent strip. It may be noted that the thickness of the foil is drawn to a much exaggerated scale for the purpose of clarity. The foil which is 0.155 mm thick or less would otherwise be no more than the thickness of a fine line and detail would therefore be obscured.

[037J The width of each groove is selected to correspond to the standard diameter of a heating element pipe 10. The pipe is usually 10mm, 15 or 22 mm in diameter and the panel will be fabricated to accommodate one dimension of pipe. The depth of the groove normally corresponds to the width of the groove and therefore to the diameter of the pipe 10. Although the depth of the groove can be greater this is usually disadvantageous as the greatest practical thickness of insulation should underlie the pipe but the pipe should not project above the groove. Thus for any pipe of diameter D the nominal height of the side walls is at least 0.5D. The nominal width of the groove will be D. The width of the flap 9 will be approximately D. Therefore when a pipe is pressed into a groove 0.5D of each flap will be pressed into direct contact with the periphery of the pipe.

[038J The width of each groove 4 is formed as an interference fit with the nominal width of the pipe 10 by under-sizing the groove by around 100 -500 pm. The elasticity of the board material and pipe allow the pipe to be pressed into the groove carrying the foil flaps with it and be gripped by the interference fit thus produced. This is useful as the pipe is delivered as a coil and tends to try to recover its set shape and pull out of the panels during installation.

[39] The material of the board may be fragile so to protect the board a protective layer 11 may be applied to the upper surface of the foil overlying each land and to the lower face of the board. The protective layer may be any of fleece, mortar, glass fibre, polymeric fibre, rubber or rubber foam. The protective layer on overlying the foil is selected to have good thermal conductance. Conversely the protective layer underlying the board will have poor thermal conductance. The protective layer may also be selected to improve the acoustic properties of the floor usually to resist sound transmission.

[40] The second embodiment of the invention is generally similar to the first as regards the structure of the board 1 protective layers location and dimensioning of the grooves. However the foil strips are, during fabrication of the panel laid onto the lands as shown in figure 4. The first strip 12.1 is laid flush against the first land 7.1 between the longitudinal edge of the board and the first groove 4.1 (to the left in figure 4) up to a midline in the longitudinal direction. The second strip 12.2 partially overlaps the first strip 12.1 and completely overlaps the first groove 12.2 and extends out over the second land and beyond the midline of the second land 7.1. The third strip 12.3 overlaps the second strip 12.2, the second groove 4.2 and the third land 7.3. A similar pattern is repeated out to the fifth land (not shown) adjacent the opposite (right hand) longitudinal edge where the pattern ends in a manner similar to the first land 7.1.

[41] Once the strips have been loosely applied to the upper surface of the whole board a press assembly comprising four presses 13.1, 13.2 (only two are illustrated) is pressed down onto the strips 12.2, 12.3 overlying the grooves 4.1, 4.2. The presses are cylindrical bars of similar shape and size to the pipe 10. The strips are thus pressed into the grooves to take up the shape of and line each groove. The material of the strips slips sideways across the lands towards each associated groove to allow the groove to be fully lined with foil. The width of each strip is selected to provide sufficient material so that a portion of the strip remains to overlying the land and butting up against the adjacent strip as illustrated in figure 5. Substantially the whole of each land is covered by thermal dispersion foil in communication with the foil in each groove.

[42] The strips of pressed foil are then secured to the board 1. The strips may be secured by applying a delayed setting adhesive between the board and the strip, which may usefully serve as a lubricant during pressing. The adhesive may time set or heat set.

[43] As with the first embodiment protective layers 11 may be applied to the strip overlying the lands and to the underlying face of the board.

[44] Figure 7 illustrates plurality of floor panels according to the first embodiment used in preparing and underfloor heating installation. The floor panels are laid onto a substrate 13 parallel to each other and end to end so that the grooves 4 are coextensive. Flexible pipe 10 is laid into the grooves 4 and pressed down to engage the foil flaps and pipe into each groove. The pipe is laid in a zig zag pattern with the pipe 10 being turned through substantially 180 degrees at each end of the arrangement of panels. To facilitate turning the pipe 10 and end-piece 14 is provided formed from a similar material to the board 1. The end-piece 14 is of the same thickness as the floor panel and has a shelf 15 formed to the same depth as the groove 4. When the pipe has been turned and emplaced the end piece may be covered with protective reinforcing panel 16. When the panels have been laid to tile across the substrate which is to provide underfloor heating a decorative and/or hardwearing floor such as floor tiles 17 can be laid onto the floor panels.

Claims (1)

1. CLAIMSA floor panel comprising a board formed of a thermal insulating material having an upper surface and lower surface; a groove formed in the upper surface so that the upper surface to either side of the groove forms a land, said groove dimensioned to closely receive a heating element; a pair of strips of flexible thermally conductive foil; a first of said foil strips attached to the land to one side of the groove and the second of said strips attached to the land to the other side of said groove, characterized in that each strip overlies or underlies the other strip at least where each overlies the groove, such that when a heating element is pressed against the edges of the strips overlying the groove the edges are pressed down into the groove to closely conform to the periphery of the heating element.A floor panel according to claim 1 wherein the first and second strips overlap substantially by the width of the groove.A floor panel according to claim 1 or claim 2 wherein the groove has an arcuate, concave base and upstanding side walls extending to the upper surface.A floor panel according to claim 1 wherein the groove is dimensioned to provide an 1. 2. 3. 4.interference fit with a standard sized heating element and the foil whereby the foil is pressed into intimate contact with the heating element to maximize heat conductance.A floor panel according to any one of the preceding claims wherein the board has more than one parallel spaced groove and the strips attached to the land are arranged to have edges overlapping both adjacent grooves. 5. 6.A floor panel according to any one of the preceding claims wherein a layer of protective material is secured to the strip overlying each land.A floor panel according to claim 6 wherein a layer of protective material is secured to the lower surface of the board.A floor panel according to claim 6 or claim 7 wherein the protective material is one of: fleece, mortar, glass fibre, polymeric fibre, rubber or rubber foam.A method of manufacturing a floor panel comprising: shaping a board of thermally insulating material to have an upper surface and a lower surface; forming a groove in the upper surface so that the upper surface to each side of the groove forms a land; securing a first strip of thermally conductive foil to the land to one side of the groove so that flap of the foil overlaps substantially the whole of the groove; securing a second strip of thermally conductive foil to the land on the other side of 7. 8. 9.the groove so that the edge of the second strip forms a flap overlapping substantially the whole groove and the flap of the first strip.A method according to claim 9 comprising the step of applying each foil strip in a substantially flat and undeformed condition.A method according to claim 9 or claim 10 comprising the step of sizing and shaping the groove to form an interference fit with a heating element of standard size when the heating element is pressed into the groove with the foil flap. 10. 11. 12.A method according to any one of claims 9 to 10 comprising forming the board with a plurality of laterally spaced parallel grooves.A method according to anyone of claims 9 to 12 comprising the step of securing a thermally conductive protective layer over the portion of strip overlying the land.A method according to any one of claims 9 to 13 comprising the step of securing a thermally insulating protective layer to the lower surface of the board.A method according to any one of claims 13 or14 wherein the protective layer is one of: fleece, mortar, glass fibre, polymeric fibre, rubber or rubber foam A floor panel for underfloor heating comprising a board of thermally insulating material having an upper surface and lower surface; 13. 14. 15. 16. 2Da groove formed in the upper surface dimensioned to closely receive a heating element so that the upper surface to each side of the groove forms a land; a strip of flexible thermally conductive foil attached to the land to each side of the groove and extending into the groove to conform to the cross sectional shape of the groove so that in use, when a standard heating element is pressed into the groove the heating element is in intimate contact with the foil lining the groove.A floor panel according to claim 16 wherein the groove is sized so that in cooperation with the foil it forms an interference fit between the groove, the foil and the heating element. 17. 18.A floor panel according to claim 16 or 17 having a plurality of parallel laterally spaced grooves and a corresponding number of foil strips, wherein the portion of each foil strip covering the land substantially abuts an adjacent strip.A floor panel according to one of claims 16 to 18 wherein a layer of protective material is secured to the strip overlying each land.A floor panel according to one of claims 16 to 18 wherein a layer of protective material is secured to the lower surface of the board.A floor panel according to claim 19 or 20 wherein the protective material is one of: fleece, mortar, glass fibre, polymeric fibre, rubber or rubber foam. 19. 22.A method of manufacturing a floor panel comprising the steps of: forming a board of a thermally insulating material to have a lower surface and an upper surface; forming a groove in the upper surface sized and shaped to receive a heating element; applying a foil strip to the upper surface so that the strip wholly overlies the groove and at least part of each adjacent land; applying a press to the foil overlying the groove so that the foil is pressed down into the groove and conforms to the sides and bottom of the groove in order to line the groove A method according to claim 22 wherein the foil forming the strip on application is substantially flat and undeformed prior to application of the press.A method according to one of claims 22 or 23 wherein the press comprises an elongate rigid rod of at least the length of the groove having a cross section complementing the cross section of at least the bottom of the groove. 23. 25.A method according to any one of claims 22 to 24 wherein the press is applied to descend uniformly along its length into the groove. 26.A method according to claim 25 wherein the board comprises a plurality of parallel laterally spaced grooves and the press comprises a corresponding number of rigid rods configured to be simultaneously received into each groove of a board.A method according to claim 26 wherein at the time the strips are laid onto the lands the strips are not fastened to the lands and overlap adjacent strips so that, as the strips are drawn into the grooves the edges of the strips overlying the lands move laterally until the groove is lined and the edges of adjacent strips are abutting. 27. 28.A method according to any one of claims 22 to 27 wherein the strips are secured to at least to the respective underlying lands after application of the press.An underfloor heating system comprising a floor panel and a heating element; said floor panel made of a board of a thermal insulating material having an upper surface and lower surface; a groove formed in the upper surface so that the upper surface to each side of the groove forms a land, a pair of strips of flexible thermally conductive foil; a first of said foil strips attached to the upper surface to one side of the groove and the second of said strips attached to the upper surface to the other side of said groove, edge regions of each said strip extending more than half the width of the groove into the groove to line the walls of each groove; 29.a heating element pressed into the groove to engage the foil and the groove and retained by an interference fit between the groove and the heating element.An underfloor heating system comprising a floor panel and a heating element; said floor panel made of a thermal insulating material having an upper surface and lower surface; a groove formed in the upper surface so that the upper surface to each side of the groove forms a land; a strip of thermally conductive foil attached to each land and extending into the groove to conform to the cross section of groove; and a heating element pressed into the groove and retained by an interference fit between the heating element, the foil and the groove whereby the foil is pressed into intimate contact with the heating element. 30.