GB2548319A - Temperature control system - Google Patents

Abstract

A support structure for a heating or cooling system 1 comprising a support layer (3, 6, 7) with a plurality of projections 7 positioned in a grid to form first and second channels 5, to accommodate thermal elements 2 on one side of the layer and a viscous layer 8 on the opposite side of the support layer, wherein the viscous layer is at least 0.15mm thick. The viscous layer provides the contact between the support layer and the underlying substrate (e.g. the sub-floor in the case of an underfloor system 12, fig 4) and may transpose the elastic stress due to expansion and contraction within the system's construction, that could otherwise cause a mechanical failure, to a stress and strain within the viscous layer. The viscous layer may be non-drying and also form the adhesive layer. The structure may further comprise a layer of thermal insulation (13, fig. 5).

Description

Temperature control system

The invention relates to heating and cooling systems for use within floors, walls or ceilings of buildings. In particular it may relate to underfloor heating systems in which heating is provided by heating cables or pipes fitted to a mat or panel.

Heating and cooling systems which use the floor, wall or ceiling surface as the heat exchange surface require either an embedded heat source or heat sink, commonly in the form of electrically resistive heating cables, or an embedded distribution system of pipes carrying a fluid or gas, that has been either heated or cooled by a connected heat source or heat sink. These may hereafter be referred to as the thermal element(s). While a plurality of thermal elements may be used, it is common for a single thermal element (e.g. a single cable or a single pipe) to be used. A single thermal element is typically laid in a serpentine fashion on the floor so as to distribute its heating or cooling as evenly as possible.

To ensure a regular temperature distribution of the emitting surface, it is important to space the thermal element at equidistant intervals, e.g. by looping back and forth across the emitter area.

The act of heating and/or cooling these exposed surfaces produces shear stress coplanar to the isotherms, created by the thermal element while it is active. This sheer stress can cause mechanical failure of the construction if it exceeds the limits of any individual material or bond within the system construction.

Some underfloor heating installations employ an intermediate structure fitted between a main floor and a sub-floor. The main floor is the upper structure that is presented to the user and is typically a decorative floor layer, e.g. tiles, solid wood, laminate, etc. The sub-floor is the main structural floor of the building and is typically either concrete or wood. The intermediate structure provides support for the main floor as well as providing protection for the wires or pipes which are laid therein (e.g. protection from footfall during installation and protection from crushing after installation).

While the remainder of this document discusses underfloor heating systems, it will be appreciated that the principles discussed apply equally to installations in other surfaces such as walls and ceilings. Also, fluid based systems that achieve heat exchange by flowing a liquid (typically water) through pipes can be used for cooling as well as heating. It will be appreciated that while the remainder of this document is more focused on heating installations, the principles also apply equally to cooling systems.

Heating and cooling systems, whether electrical or hydronic (water based), need to accommodate expansion and contraction of the various structural elements of the installation. Such movement may be due to temperature variations (e.g. during start-up and cool-down of the heating elements) or due to drying out of structures after installation (e.g. drying of concrete or timber leads to shrinkage). The main area of stress is between the sub-floor and the intermediate structure as this is typically where the greatest temperature difference occurs due to contact with the ground (or other surfaces), and is also where contraction due to drying will occur. Thermal stresses are dependent on the temperatures, thermal conductivities and thermal expansion coefficients.

According to a first aspect, the invention provides a support structure for a heating or cooling system comprising: a support layer to accommodate one or more thermal elements on one side of the layer; and a viscous layer provided on the opposite side of the support layer; wherein the viscous layer is at least 0.15 mm thick.

The viscous layer provides the contact between the support layer and the underlying substrate (e.g. the sub-floor in the case of an underfloor heating or cooling system)and transposes some of the elastic stress within the system's construction that could otherwise cause a mechanical failure, to a viscous stress and strain within the viscous layer.

Previously, such support layers have been firmly bonded to the underlying sub-floor structure. For example a non-viscous adhesive has been used such as tile adhesive which sets firmly after application. Alternatively, thin layers of other adhesives have been used (in some cases as a temporary adhesive to facilitate positioning of the support structure during laying of the thermal elements) to be supplemented by a stronger adhesive at a later stage. Although some of these adhesives may have some viscosity, they are applied in such a thin layer that they are not designed to take up stresses formed during expansion and contraction of the construction. This thinness of the adhesive layer has previously been considered an advantage for two reasons. Firstly, it is cost efficient to apply adhesive in as small a quantity as possible (and therefore in as thin a layer as is necessary to achieve bonding). Secondly, the industry generally seeks to minimise the total installation height by minimizing the height of all components within the system. For example in an underfloor heating installation, the heating structure and a new floor covering must be laid over an existing sub-floor structure and it is desired not to raise the new floor level any further than is necessary. During rapid thermal expansion and/or contraction, these thin adhesive layers may break apart, tearing and separating to the extent that they no longer bond the two structures together. This may be deemed an installation failure leading to high costs for repair.

The provision of a thicker viscous layer to mount the support structure ensures that sufficient viscous fluid is provided that as expansion and/or contraction takes place, the viscous fluid can flow and move with the surrounding structures, within its own plane, without tearing and losing contact. Any microtears are sufficiently small that they self-heal quickly once the movement has stopped.

Previous efforts to address the issues of expansion and contraction have either attempted to provide a sufficiently strong bond with a rigid-set adhesive that can withstand the strain, or have introduced a fabric anti-fracture layer underneath the support structure and which is bonded to the sub-structure. This fabric layer is designed to tear upon expansion of the support layer, relieving some of the stress while retaining adequate bonding to the sub-structure. However, a significant downside of this solution is that it cannot cope with contraction of the sub-floor after installation. If the sub-floor contracts, the fabric layer cannot tear because the pressure is exerted over a wide area at the perimeter. The stresses on the fabric layer never build sufficiently to cause tears, but the exposed surface of the decorative floor above is compressed by a cumulative pressure exerted by the surrounding area. The result is a risk of delamination, again potentially constituting a product failure. This delamination may be delamination of the decorative floor from the support structure, or delamination of the support structure from the subfloor. Damage to the decorative floor may also result. By contrast, the thicker viscous layer of the invention may flow to accommodate movement due to expansion and contraction of the sub-floor. Such movement may include the opening/closing of gaps within the support structure. This allows the mat (support layer), heater and final floor finish essentially to “float” above, undisturbed. Upon contraction the viscous layer will simply become very slightly thicker. This is particularly beneficial when used with a cooling system (e.g. flowing a cold fluid through pipes within the support structure) as this can lead to thermal contraction of the support layer relative to the sub-structure.

The viscous layer is preferably capable of flowing at a rate that can support an expansion or contraction rate of at least 0.1 mm per minute, preferably at least 0.5 mm per minute. The combination of viscosity and thickness determines the rate of expansion or contraction that can be accommodated by the viscous layer and thus determines the rate of differential expansion or contraction that can be accommodated by the exposed layer (e g. the decorative floor). Being able to accommodate larger rates of thermal expansion allows the system to be heated up or cooled down faster which may improve the end user's experience. The viscous layer is considered to accommodate a given expansion or contraction rate if such a rate does not cause irreversible tears or voids to be formed in the viscous layer. In cases where the viscosity and thickness of the layer does not support the maximum thermal expansion/contraction rates achievable with the thermal elements, a controller may be used (optionally in combination with a temperature sensor) to limit the temperature change and thus the expansion rate to that which can be matched by the viscous layer without irreversible damage.

The viscous layer may have a viscosity of at least 250,000 centipoise, preferably greater than 500,000 centipoise.

The viscous layer may be at least 0.2 mm thick, or it may even by at least 0.3 mm thick. Thicker layers of viscous material may be desirable for premium products that can accommodate greater rates of expansion and contraction.

Preferably the viscous layer is also an adhesive layer. The viscous adhesive layer then provides a dual purpose of adhering the support layer to the underlying structure as well as accommodating thermal expansion and contraction.

Maintaining adhesion to both the support layer and the underlying support structure during thermal expansion and contraction without irreparable damage to the viscous layer gives excellent performance, reliability and longevity to the installation.

Some adhesive formulations may lose stickiness or tackiness or fluidity over time, but the viscous adhesive layer is preferably a non-drying substance that will retain its viscous and adhesion properties throughout its operational lifetime. The retention of these properties affects the product lifetime and is therefore an important consideration. In some preferred embodiments the viscous adhesive layer comprises a polyurethane based adhesive. Such adhesives can be formulated with the desired viscosity properties and the desired non-drying property. Other polymer adhesives may also achieve these goals, but polyurethane based adhesives are readily available, inexpensive and easy to work with.

As was discussed above, other products have previously sought firm adhesion through application of a strong adhesive that is applied at a later installation stage. This typically occurs when a tile adhesive or leveling compound is applied to the upper surface of the support structure (in the case of underfloor systems) after the thermal elements have been installed. This adhesive is typically applied around the thermal elements and also acts as the main thermal conductor to distribute heat evenly across the installation. Through holes formed in the support structure of earlier products have allowed this adhesive to connect through from the upper side of the support structure (the side with the thermal elements) to the lower side (adjacent the sub-structure, e.g. sub-floor) and bond the whole installation to the sub-structure. It will be appreciated that such holes are inconsistent with the approach described according to this invention as such bonding prevents or hinders movement due to thermal expansion and/or contraction. Accordingly, it is preferred that the support layer is a substantially continuous layer without holes therethrough. The support layer is thus impermeable (or non-porous) to any adhesive applied to the side of the support structure with the thermal elements thereon. A layer of thermal insulation may be provided between the support layer and the viscous layer to provide a more rapid thermal response of the layer(s) above the support layer. Alternatively, a layer of thermal insulation may be provided such that the viscous layer is between the support layer and the thermal insulation layer. The insulation layer would be bonded to the sub-floor and would be elastic enough to expand and contract with it.

The support layer may have a layer of primer applied thereto to improve bond strength with adhesive or levelling compounds.

The support layer preferably comprises a plurality of projections designed to be capable of retaining thermal element(s) positioned adjacent thereto. Such structures are often referred to as castellated structures. The projections or castellations typically form a series of pillars around or between which the thermal elements are threaded, the projections providing support to hold the thermal elements in position along straight runs, but also providing support for changes of direction by winding around the projections (e.g. a 90 degree wind to change to a perpendicular direction). The projections may be spaced such that they grip the thermal elements firmly to prevent lateral as well as vertical movement, thus holding them securely in place during installation. Alternatively, the projections may be spaced sufficiently far apart that they do not laterally squeeze the thermal elements, but instead have a protuberance at the distal end of the projection that extends over the thermal elements in use and prevents them from riding up the side of the projection and potentially losing their positioning. In some embodiments two such projections with protuberances may be positioned a distance apart that they will not grip the thermal elements when installed, but have their protuberances facing each other such that the distance between protuberances is less than the diameter of the thermal element. Thus the thermal elements may be squeezed or snapped into position between the projections, but will not easily squeeze back out.

Many different arrangements of the projections may be used, but in preferred embodiments the projections are positioned in a grid so as to form a first set of channels and a second set of channels therebetween, the first set of channels being perpendicular to the second set of channels. In use, the thermal elements are laid in the channels in a winding pattern shaped to distribute the heating or cooling to the desired places. The channels are typically spaced closer than the optimal spacing of the thermal elements so that the installer has a choice of how and where to route the thermal elements to best fit a particular installation (e.g. rooms of different widths and shapes). The perpendicular channels intersect and cross over each other allowing the thermal elements to change direction. The channel spacing for the first and second sets need not be the same, but it is preferred that the spacing is the same so as to form a square grid.

Preferably each projection is elongate and extends diagonally between two adjacent channels of the first set of channels and also extends diagonally between two adjacent channels of the second set of channels. The elongate and diagonally arranged projections have a particular benefit that in use they make essentially point contact with the thermal element(s) while the thermal elements are running in a straight line down one of the aforementioned channels. A greater contact area will only result when a thermal element winds around a projection when changing direction. This reduction in contact area between the thermal elements and the support structure results in a greater area of contact between the thermal elements and thermally conductive filler that is subsequently provided around the thermal elements, e.g. adhesive or leveling compound. The thermally conductive filler conducts heat much more efficiently across the installation than material of the support structure and therefore this arrangement results in better heat transfer, fewer hot spots and cold spots, lower thermal gradients and thus lower stresses within the structure.

The open and regular grid arrangement of channels together with the low contact area achieved with the diagonal elongate projections also ensures that there are many easy heat flow paths for heat to be conducted around the structure. The channels that are not used to accommodate thermal elements instead provide heat conduction paths around the structure.

Each projection may be oriented so that the arrangement of projections is symmetrical about any channel of the first set of channels. One such structure results in a herringbone pattern of projections on the structure. Alternatively, each projection may be oriented so that the arrangement of projections is symmetrical about any channel of the first set and also symmetrical about any channel of the second set. With this arrangement there are regular projections along any channel that provide turning points in either direction around the long side of the elongate projection (which provides a larger radius of curvature and results in less resistance (either electrical resistance in a cable or flow resistance in a fluid conduit). This arrangement also results in contact points along a straight run of thermal element being arranged in groups of four with the intervening area (between two groups) providing a large open area which is good for heat conduction to other parts of the structure.

Before installation, it is desired to protect the viscous adhesive layer from adhering to anything else and therefore the support structure preferably further comprises a removable release sheet attached to the viscous adhesive layer. The release sheet thus sandwiches the viscous adhesive layer between the release sheet and the support layer and can be peeled off just ahead of installation.

According to another aspect, the invention provides a method of manufacturing a support structure for a heating or cooling system, comprising: forming a support layer that is arranged to accommodate one or more thermal elements on one side of the layer; and applying a layer of viscous adhesive on the opposite side of the support layer to a thickness of at least 0.15 mm.

All of the preferred features described above in relation to the support structure also apply to the method of manufacture.

The support layer may be formed by any suitable process such as moulding, but in some embodiments may be vacuum formed. It may also be made from a variety of materials, but is preferably a plastic material with sufficient rigidity to withstand the weight of a reasonably heavy decorative floor structure (such as stone tiles) with additional loads from normal use (furniture or people walking on top of it).

According to yet another aspect, the invention provides a method of constructing a heating or cooling system comprising: adhering a support structure as described above (optionally including any of the optional or preferred features also described above) to a first structure by adhering the viscous adhesive layer to a first structure; affixing one or more thermal elements to the side of the support layer opposite the viscous adhesive layer; and affixing a decorative second structure to the side of the support layer opposite the viscous adhesive layer. The decorative second structure may for example be any of: tiles, wood, laminate, carpet, etc. If provided, the release sheet is removed before the step of adhering the viscous layer to the first structure.

The arrangement of projections is considered to be independently inventive and therefore according to a further aspect, there is provided a support structure for a heating or cooling system, comprising: a plurality of projections designed to be capable of retaining one or more thermal elements positioned adjacent thereto; wherein the plurality of projections are positioned in a grid so as to form a first set of channels and a second set of channels therebetween, the first set of channels being perpendicular to the second set of channels; and wherein each projection is elongate and extends diagonally between two adjacent channels of the first set of channels and also extends diagonally between two adjacent channels of the second set of channels. This arrangement has the heat distribution advantages described above. The preferred features described above also apply. For example, each projection may be oriented so that the arrangement of projections is symmetrical about any channel of the first set of channels. Alternatively each projection may be oriented so that the arrangement of projections is symmetrical about any channel of the first set and also symmetrical about any channel of the second set.

Preferred embodiments of the invention will be described, by way of example only, and with reference to the accompanying drawings in which:

Fig. 1 shows a perspective view of a castellated mat with an electric heating cable installed therein;

Fig. 2 shows a close up of the mat and cable of Fig. 1;

Fig. 3 shows a side-view of the mat and cable of Fig. 1;

Fig. 4 shows a side view of a mat positioned on a sub-floor;

Fig. 5 shows another embodiment with insulation provided above the viscous layer; and

Fig. 6 shows a further embodiment with insulation below the viscous layer.

Fig. 1 shows an embodiment of an underfloor heating mat (or panel) 1 with an electric heating cable 2 disposed thereon. The mat 1 forms a support structure which is designed to be used as an intermediate structure in a heating or cooling system. In such installations, the mat 1 is designed to lie on top of a sub-floor such as a wooden or concrete floor structure and to have a decorative floor such as tiles, wood or laminate laid above and on top of it.

The mat 1 is a castellated mat having a regular, repeating pattern of castellations (pillars or projections) 3 projecting up from a flat base 4. The cable 2 is slotted into channels 5 that are formed between the projections 3. The projections 3 are taller than the height of the cable 2 so that the cable 2 will not be squashed or damaged by heavy objects placed on the top of the projections 3. The projections 3 are sufficiently rigid that they can support the weight people walking around on them during installation. They can also support the weight of the decorative floor (such as stone tiles), furniture and people walking around on the floor after installation (although there will typically be an additional adhesive layer (such as tile adhesive or leveling compound) added between the projections 3 before the decorative floor is laid, adding to its rigidity.

The projections are positioned so as to form a grid arrangement. The grid forms two sets of perpendicular channels 5 which may be identified as a first set of channels 5a (extending horizontally in Fig. 1) and a second set of channels 5b (extending vertically in Fig. 1). These two sets of channels form a rectangular grid such that each channel of the first set 5a is perpendicular to each channel of the second set 5b. In use, the thermal element(s) 2 are laid in the channels 5, e.g. in a winding pattern, back and forth, shaped to distribute the heating or cooling to the desired places according to the shape and layout of the room. The channels 5 on the mat 1 are typically spaced closer than the optimal spacing of adjacent runs of the cable 2 so that the installer has a choice of how and where to route the cable 2 to best fit a particular installation (e.g. rooms of different widths and shapes). The perpendicular channels 5 intersect and cross over each other allowing the cable 2 to change direction. The channel spacing for the first and second sets 5a, 5b is the same in this embodiment so that they form a square grid on the mat 1.

Each projection 3 is elongate in shape and extends diagonally between two adjacent channels 5a of the first set of channels and also extends diagonally between two adjacent channels 5b of the second set of channels. More specifically, each projection is substantially oval shaped when viewed from above. The projections 3 all have the same height and have flat tops 7 that together form a support plane for the decorative floor to be laid on top.

As is best illustrated in Figs. 1 and 2, the elongate and diagonally arranged projections 3 make essentially point contact with the sides of the cable 2 as it runs in a straight line down one of the channels 5. This has the benefit that the direct thermal transfer between the cable 2 and the projections 3 (i.e. heat transfer to the mat 1) is minimised. Heat will instead be transferred to the heat conducting adhesive or leveling compound that is used to fill the channels 5 after the cable 2 has been laid. This material is a much better heat conductor and transfers heat better to other parts of the mat 1, resulting in a more even heat distribution (reducing the difference between minimum and maximum surface temperatures). A greater area of contact between a projection 3 and the cable 2 will result when the cable 2 winds around a projection 3 when changing direction, e.g. from a first channel 5a to a second channel 5b. However, as these turning points are generally a small fraction of the overall length of the cable 2, they do not adversely affect the thermal conduction greatly.

The open and regular grid arrangement of channels 5 together with the low contact area achieved with the diagonal elongate projections 3 also ensures that there are many easy heat flow paths for heat to be conducted around the mat 1. All of the channels 5 that are not used to accommodate the cable 2 instead provide heat conduction paths around the mat 1.

Each projection 3 is oriented so that the arrangement of projections 3 is symmetrical about any channel 5a of the first set and also symmetrical about any channel 5b of the second set. With this symmetry there are regular projections 3 along any channel 5 that provide turning points in either direction around the long side of the elongate projection 3 which provides a larger radius of curvature than around the tips and thus results in less resistance (either electrical resistance in a cable or flow resistance in a fluid conduit). This arrangement also results in contact points along a straight run of cable 2 being arranged in groups of four with the intervening area (between two groups) providing a large open area which is good for heat conduction to other parts of the mat 1.

As can be seen in Fig. 3, the projections 3 are spaced sufficiently far apart that they do not laterally squeeze the cable 2, but instead have a protuberance 6 at the distal end of the projection that extends over the installed cable 2 thus preventing it from riding up the side of the projection 3 or easily lifting out of the channel 5 and thereby losing its positioning. Two such projections 3 with protuberances 6 are positioned a distance apart that they will not grip the cable 2 when installed, but have their protuberances 6 facing each other such that the distance between protuberances 6 is less than the diameter of the cable 2. Thus the cable 2 must be squeezed or snapped into position between the protuberances 6 and once in position will not easily squeeze back out.

Fig. 3 also shows the viscous adhesive layer 8 that is provided on the underside of the mat 1 for adhering the mat 1 to the sub-floor. The viscous adhesive layer 8 is a minimum of 0.15 mm thick which allows the adhesive viscous layer 8 to deform when stress is applied during thermal expansion and contraction. With thinner layers, the amount of relative movement between the two surfaces of the viscous layer 8 (i.e. between the underside of the mat 1 and the upper surface of the subfloor) would result in voids or tears in the adhesive viscous layer 8 that are unacceptable in terms of adequately bonding the mat 1 and the decorative floor above it to the sub-floor beneath. The rate of thermal expansion is also important as too high a rate of movement can cause tears and voids in a thin layer. By contrast, the thicker layer of viscous adhesive 8 provided by the invention can accommodate the typical amounts and rates of thermal expansion that are present in a typical installation without requiring any other forms of prevention or compensation. The thick viscous fluid layer 8 can change shape faster than a thinner one and can accommodate a greater overall range of movement.

Therefore in some embodiments the castellated mat 1 comprises a plastic membrane with a series of restraints (pillars or projections) 3 extending upwardly from its base 4 and forming tracks (or channels) 5 at regular intervals within which a thermal element 2 (e.g. electrical heating cable or fluid-carrying pipe) can be installed. The main function of the restraints 3 is to constrain the thermal element 2 within the tracks 5 and to provide some protection to the thermal element 2 from mechanical damage.

The castellated mat 1 includes a layer 8 of viscous material which can absorb shear stress within the installed plane by permitting shear strain, whilst maintaining its bond with the layers adjacent to it within the construction (i.e. the lower surface of the plastic membrane and the upper surface of the sub-floor or other base construction surface).

The castellated mat 1 may include a layer of thermal insulation 13 below the castellated membrane 1 and either above or below the viscous layer 8 to provide a more rapid thermal response of the layer(s) above the castellated membrane.

Fig. 4 shows the mat 1 with viscous layer 8 mounted directly to a sub-floor 12 without any intervening thermal insulation. Fig. 5 shows the mat 1 with a layer of thermal insulation 13 sandwiched between the support layer and the viscous layer 8. Fig. 6 shows the mat 1 with a layer of thermal insulation provided underneath the viscous layer 8, i.e. between the sub-floor 12 and the viscous layer 8. In this embodiment the viscous layer 8 is situated between the thermal insulation 13 and the support layer. The viscous layer 8 thus still provides a layer of separation between the sub-floor 12 and the support layer which can change shape to accommodate relative expansion between these two layers.

The viscous layer 8 may also function as a self-adhesive backing to the castellated mat 1 that bonds the membrane to any structurally compatible, planar surface without the need for additional fixing methods or adhesives.

The top of the plastic membrane may have a layer of primer 10 (indicated in Figs. 4, 5 and 6) applied to improve the bond strength of adhesive or levelling compounds used over the product and/or to broaden the range of compatible compounds that can be used in combination with the castellated mat 1.

Numerous advantages of the embodiments described above may be highlighted as follows: The membrane features a series of extrusions 3 which form tracks 5 within which a thermal element 2 can be installed. The tracks 5 formed in between the extrusions 3 provide additional support for the heating element 2 and reduce the risk of mechanical damage during installation. The extrusions 3 are shaped such that the heating element 2 only makes point contact with their curved surfaces to reduce the area where the heating element 2 is in contact with the membrane 1, thus maximising the heating output of the system. The channels 5 are equally spaced from each other to minimise the risk of installing the heating element 2 at uneven spacing, which can eventually lead to cold spots/overheating in certain areas and generally unsatisfactory heating output. The flat area 7 at the top of each extrusion 3 reduces the risk of air pockets forming when the membrane 1 is covered with self-levelling compound or tile adhesive. Areas with air gaps or air pockets in the screed or tile adhesive can cause the heating element 2 to overheat and eventually burn out. The self-adhesive viscous layer 8 of the membrane 1 prevents any lateral movement in the subfloor from causing damage to the finished floor, and acts as a separating layer between the subfloor and the finished (decorative) floor. The self-adhesive viscous layer 8 stretches and slides as the subfloor is expanding or contracting, leaving the membrane base layer and finished floor unaffected. The self-adhesive viscous layer 8 can be used to attach the membrane 1 to any subfloor surface without the need of additional fixing methods, such screws, staples, tile adhesive, wood glue, etc. The self-adhesive viscous layer 8 is made of polyurethane and remains viscous throughout its operational lifetime.

With minor changes to the dimensions and spacings of the projections, the mat 1 is equally suitable for use with fluid carrying pipes (typically flexible plastic pipes). For example it is suitable for use in hydronic (water-based) underfloor heating and cooling systems.

Although the mat 1 has been described mostly in relation to underfloor heating, it is equally applicable to wall or ceiling based heating systems and is also equally applicable to cooling systems (which will typically be fluid-based).

Claims (23)

Claims

1. A support structure for a heating or cooling system comprising: a support layer to accommodate one or more thermal elements on one side of the layer; and a viscous layer provided on the opposite side of the support layer; wherein the viscous layer is at least 0.15 mm thick.

2. A support structure as claimed in claim 1, wherein the viscous layer is capable of flowing to accommodate movement due to expansion and contraction.

3. A support structure as claimed in claim 2, wherein the viscous layer is capable of flowing at a rate that can support an expansion or contraction rate of at least 0.1 mm per minute, preferably at least 0.5 mm per minute.

4. A support structure as claimed in claim 1, 2 or 3, wherein the viscous adhesive layer has a viscosity of at least 250,000 centipoise, preferably greater than 500,000 centipoise.

5. A support structure as claimed in any preceding claim, wherein the viscous layer is at least 0.2 mm thick, preferably at least 0.3 mm thick.

6. A support structure as claimed in any preceding claim, wherein the viscous layer is also an adhesive layer.

7. A support structure as claimed in any preceding claim, wherein the viscous layer is a non-drying substance.

8. A support structure as claimed in any preceding claim, wherein the viscous layer comprises a polyurethane based adhesive.

9. A support structure as claimed in any preceding claim, further comprising: a layer of thermal insulation between the support layer and the viscous layer.

10. A support structure as claimed in any preceding claim, further comprising: a layer of thermal insulation; wherein the viscous layer is provided between the support layer and the thermal insulation layer.

11. A support structure as claimed in any preceding claim, wherein the support layer has a layer of primer applied thereto to improve bond strength with adhesive or levelling compounds.

12. A support structure as claimed in any preceding claim, wherein the support layer is a substantially continuous layer without holes therethrough.

13. A support structure as claimed in any preceding claim, wherein the support layer comprises a plurality of projections designed to be capable of retaining thermal element(s) positioned adjacent thereto.

14. A support structure as claimed in claim 13, wherein the projections are positioned in a grid so as to form a first set of channels and a second set of channels therebetween, the first set of channels being perpendicular to the second set of channels.

15. A support structure as claimed in claim 14, wherein each projection is elongate and extends diagonally between two adjacent channels of the first set of channels and also extends diagonally between two adjacent channels of the second set of channels.

16. A support structure as claimed in claim 15, wherein each projection is oriented so that the arrangement of projections is symmetrical about any channel of the first set of channels.

17. A support structure as claimed in claim 15, wherein each projection is oriented so that the arrangement of projections is symmetrical about any channel of the first set and also symmetrical about any channel of the second set.

18. A support structure as claimed in any preceding claim, further comprising a removable release sheet attached to the viscous layer.

19. A method of manufacturing a support structure for a heating or cooling system, comprising: forming a support layer that is arranged to accommodate one or more thermal elements on one side of the layer; and applying a viscous layer on the opposite side of the support layer to a thickness of at least 0.15 mm.

20. A method of constructing a heating or cooling system comprising: applying a support structure according to any of claims 1 to 18 to a first structure by applying the viscous layer to a first structure; affixing one or more thermal elements to the side of the support layer opposite the viscous adhesive layer; and affixing a decorative second structure to the side of the support layer opposite the viscous adhesive layer.

21. A support structure for a heating or cooling system, comprising: a plurality of projections designed to be capable of retaining one or more thermal elements positioned adjacent thereto; wherein the plurality of projections are positioned in a grid so as to form a first set of channels and a second set of channels therebetween, the first set of channels being perpendicular to the second set of channels; and wherein each projection is elongate and extends diagonally between two adjacent channels of the first set of channels and also extends diagonally between two adjacent channels of the second set of channels.

22. A support structure as claimed in claim 21, wherein each projection is oriented so that the arrangement of projections is symmetrical about any channel of the first set of channels.

23. A support structure as claimed in claim 22, wherein each projection is oriented so that the arrangement of projections is symmetrical about any channel of the first set and also symmetrical about any channel of the second set.