Patent Description:
The present invention also relates to a heating system as defined in the preamble of claim <NUM>.

The present invention also relates to a method for installing a heating system as defined in claim <NUM>.

The following background information is a description of the background of the present invention, which thus not necessarily has to be a description of prior art.

One of our times big challenges is to reduce the overall energy consumption in the world. In many parts of the world, houses, apartments, offices, shops, factories and/or other public or non-public spaces, need to be heated in order to provide an acceptable environment for people spending time in these spaces. Such heating thus needs to provide a comfortable temperature at the same time as the energy consumption should be kept at a minimum.

Underfloor heating may be used for reducing the energy consumption at the same time as an acceptable temperature/environment is provided. It is nowadays common to install underfloor heating using warm water or electricity as a heat source when stone and/or ceramic tiles are used for covering the floor. Also, underfloor heating may be used when wooden floors, such as e.g. parquet flooring, are used for covering the floors.

Traditionally, the heat used for providing the underfloor heating has been created by warm water flowing in pipes/tubes under the floor boards and/or by electricity flowing through resistance in sheet materials arranged under the floor boards. Such a known solution is described in <CIT>, in which a mat/sheet "denoted heating device <NUM>" in the document is arranged under a "floor covering <NUM>", i.e. under the actual floor boards. These pipes/tubes and/or sheet materials are thus arranged underneath the wooden floor, or underneath the stone and/or ceramic tiles. These traditional solutions have a disadvantage in that they are not very efficient in providing the heat into the space where it is actually needed, i.e. into the space above the wooden floor, and/or above the stone and/or ceramic tiles. This is due to the fact that the heat is created underneath the wooden floor, or underneath the stone and/or ceramic tiles, and thus needs to be transported through the entire wooden floor, and/or through the entire stone and/or ceramic tiles to reach the space where the e.g. people are to be present, i.e. to reach the space which should be heated. Also, a large part of the created heat is transported in the opposite direction, i.e. away from the wooden floor, or the stone and/or ceramic tiles, which also means away from the space which should be heated. Thus, a lot of the created heat is lost in such traditional heating systems, wherefore the heating system is inefficient and wastes energy.

In a prior art solution shown in <CIT>, a flooring board is instead provided with an embedded heating foil within the board, which is arranged for creating heat when being supplied with electrical energy. Hereby, the created heat is much more efficiently provided to the space in which it is needed, since the heat is created within the actual flooring board, instead of underneath it.

In a prior art solution shown in <CIT>, a floor panel for installation into a floor heating is described. The floor panel is provided with a heating means on a bottom surface and has side edges which are provided with a panel connection for being connected with further panels. For the installation of the floor panel into a floor heating, a heating connection is provided on at least one of the side edges of the floor panel. In a prior art solution shown in <CIT>, a heatable covering system is described which comprises covering panels which are provided with coupling units at longitudinal edges for interconnecting the covering panels. The covering panels are further provided with electrical heating means.

Another prior art solution is known from <CIT>.

The flooring board shown in <CIT> has, however, a number of problems related to the power supply to the flooring boards. The flooring board has electrical connecting means arranged on the grooves and tongues of the quick coupling joints being used for mechanically coupling the flooring board together with other flooring boards. Since the electrical connecting means are arranged on the grooves and tongues of the joint, the electrical connecting means will also experience small movements when pressure is applied on the flooring boards. The parts of the joints, i.e. the grooves and the tongues of the joints, move slightly every time for example a person walks on the flooring boards. Hereby, the electrical connecting means in <CIT> will become worn out after some use. Also, even a lost contact may result from the wear of the electrical connecting means, whereby the heating function is lost. Also, a short circuit may be caused by the wear of the electrical connecting means, which may be hazardous due to e.g. a risk of fire. These possible problems are of course very unfortunate, especially for a floor having a long expected life time. Such a floor may have to be exchanged after a considerably shorter time than expected due to a malfunctioning heating function of the floor.

It is therefore an object of the present invention to provide a panel, a heating system, and a method that solve at least some of the above stated problems and/or disadvantages.

The object is achieved by the above mentioned panel according to the characterizing portion of claim <NUM>.

According to and embodiment of the present invention, the first and second end portions of the at least one electrical end connector are arranged in the at least first and second longitudinal grooves, respectively.

According to and embodiment of the present invention, the at least one electrical end connector is at least partly resilient and includes an at least partly protruding portion between the first and second end portions, such that the at least partly protruding portion protrudes at least partly from the one or more of the first and second end panel coupling means in its relaxed state, when the first and second end portions of the at least one electrical end connector are arranged in the at least first and second longitudinal grooves, respectively.

According to and embodiment of the present invention, the panel further includes first and second panel end recesses adjacent to at least one of the first and the second end sides, respectively, the first and second panel end recesses having at least first and second distances to the first and second longitudinal sides, respectively, and being arranged for at least partly receiving the first and second end portions of the at least one electrical end connector.

According to and embodiment of the present invention, the at least one electrical end connector includes a supporting member attached to the first and second end portions, the supporting member protruding from the one or more of the first and second end panel coupling means and being arranged for being inserted into a supporting notch of an adjacent panel being coupled to the panel, thereby creating a force F acting against a torque Tq provided to the panel for achieving a mechanical coupling between the panel and the adjacent panel.

According to an embodiment of the present invention, the panel also includes at least first and second longitudinal coupling elements arranged in the at least first and second longitudinal grooves from the first end side to the second end side, respectively. Then, the first and second end portions of the electrical end connector are arranged for being electrically connected to the heat providing layer by means/use of the at least first and second longitudinal coupling elements.

According to an embodiment of the present invention, at least first and second surfaces of the at least first and second longitudinal coupling elements facing the heat providing layer are aligned with a surface of the base layer outside of the at least first and second longitudinal grooves and facing the heat providing layer.

According to an embodiment of the present invention, the first and second end portions of the at least one electrical end connector are electrically connected to the heat providing layer by the heat providing layer being arranged between the covering layer and the at least first and second longitudinal coupling elements, and being attached to the at least first and second longitudinal coupling elements.

According to an embodiment of the present invention, the at least first and second longitudinal coupling elements are arranged for pressing the heat providing layer and the first and second end portions of the at least one electrical end connector against each other in order to provide an electrical connection between the heat providing layer and the at least one first and at least one second end portions of the at least one electrical end connector.

According to an embodiment of the present invention, the electrical connection is provided by the heat providing layer being arranged in the at least first and second longitudinal grooves between the base layer and the at least first and second longitudinal coupling elements, whereby the at least first and second longitudinal coupling elements are arranged for pressing the heat providing layer and the first and second end portions of the at least one electrical end connector, respectively, against each other.

According to an embodiment of the present invention, the first and second end portions of the at least one electrical end connector include first and second electrically conducting tongues, respectively, arranged for being in electrical contact with at least first and second longitudinal coupling elements arranged in the at least first and second longitudinal grooves from the first end side to the second end side, respectively, of the panel and with a corresponding at least first and second longitudinal coupling elements of an adjacent panel being coupled to the panel.

According to an embodiment of the present invention, the first and second electrically conducting tongues are at least partly wave-formed.

According to an embodiment of the present invention, one or more of the first and second end portions of the at least one electrical end connector are at least partly resilient, thereby being arranged for snap locking of at least one of at least one corresponding first and second end panel coupling means of at least one adjacent panel.

The above mentioned object is also achieved by the above mentioned heating system according to the characterizing portion of claim <NUM>.

According to an embodiment of the present invention, the electrical energy providing arrangement is located according to one in the group of:.

According to an embodiment of the present invention, the electrical energy is provided by first and second polarities being supplied to the first and second electrical power supply end connectors of the first end side of a panel, or to a corresponding first end side of an adjacent panel coupled directly or indirectly to the first end side of the panel.

According to an embodiment of the present invention, the electrical energy is provided by:.

The above-mentioned object is also achieved by the above mentioned method for installing the heating system according to the present invention, according to the characterizing portion of claim <NUM>.

According to an embodiment of the present invention, the method includes:.

The panel and heating system according to the present invention provide for an energy efficient and durable heating of essentially all sorts of spaces.

By integrating the heat providing layer into a construction panel, such as e.g. a flooring panel, a wall panel and/or a ceiling panel, it is possible to efficiently, precisely and reliably regulate the indoor climate/temperature in spaces delimited by a floor, walls and a ceiling at least partly including such panels.

The heat providing layer is arranged very close to the space to be heated, since it is located directly under the covering/decorative layer. Hereby, the created heat may be very efficiently transported to the space to be heated when the panel according to the present invention is used. By this efficient heat transportation to the space to be heated, the consumption of electric energy being used for creating the heat is minimized.

The panel according to the present invention is cuttable in the sense of being possible to cut off and still be used for laying floors. This is due to the fact that the locations of the first and second longitudinal grooves are well defined, which also results in a well-defined placement of the first and second electrical end connectors and/or the first and second electrical power supply end connectors placed in the first and second grooves. Hereby, a cut off panel may be laid against another cut off panel, or may be laid against a whole panel, and would still be provided with a reliable supply of electrical energy for generating the heat in the panel, since the first and second electrical end connectors and/or the first and second electrical power supply end connectors of the panels will fit/match/meet such that a connection is made.

The electrical end connectors and/or the electrical power supply end connectors of the panel according to the present invention are at least partly separated from the mechanical panel joint coupling, i.e. from the joint coupling mechanically holding panels together. Hereby, the electrical end connectors and/or the electrical power supply end connectors are also protected from the many movements of the parts of the mechanical panel joint, and from the component wear these movement could result in.

By usage of the present invention, a secure and reliable power supply to the panel is assured. Also, the design of the electrical end connectors according to the present invention simplifies mechanical coupling of panels together, at the same time as a stable electrical coupling is provided.

Also, the end connectors of the panel according to the present invention provides for a reliable and secure electrical contact to corresponding end connectors of adjacent panels. Hereby, electrical energy to be used for creating the heat in the heat providing layer reliably reaches each one of coupled panels, and therefor also reaches the heat providing layers of each one of the panels.

The panel according to the present invention may be produced and installed cost efficiently. Since the heat may be created by use of low voltages, such as <NUM>-<NUM> Volts, e.g. approximately <NUM> Volts or approximately <NUM> Volts, the panels may even be installed by a layman, i.e. by a non-professional. Thus, by installation of the panels according to the present invention, there may not be a need for an electrician to be present, depending on laws and regulations where the panel is to be installed/used, which dramatically reduces the total cost for an end user, e.g. a house owner. Prior art electrical underfloor heating systems are often driven by much higher voltages, e.g. <NUM> Volts, which must be installed by a certified electrician.

Some known underfloor heating systems include a lower voltage mat/sheeting creating the heat, which is arranged under the wooden floor or underneath the stone and/or ceramic tiles. One such example is the above-mentioned heating device <NUM> in <CIT>, which is arranged under the floor covering <NUM>. This arrangement results in considerable energy losses as described above. Also, this prior art lower voltage mat/sheeting is often difficult to properly install, wherefore a skilled person often must adapt e.g. the size of the mat/sheeting to fit the area to be covered by the floor. This increases the costs for installation of the floors.

The panel according to the present invention, however, already itself includes the heat providing layer, and does thus not need any heat creating mats to be installed underneath it.

As a non-limiting example, a power per floor area in an interval of approximately, <NUM>-<NUM> W/M<NUM>, or <NUM>-<NUM> W/m<NUM> may be used for creating the heat. The used power per floor area may be seen as a balance between differing characteristics for the floor and/or heating. Higher power generally results in shorter heat providing circuits, which is an advantage when cutting off the panels since the part of the panel without heating due to the cutting off becomes small. However, for lower powers per floor area, the resistances of the heat providing circuits are less critical than for higher powers and lower resistances.

Detailed exemplary embodiments and advantages of the panel, the heating system, and the method according to the invention is hereafter described with reference to the appended drawings illustrating some preferred embodiments.

Embodiments of the invention are described in more detail with reference to attached drawings illustrating examples of embodiments of the invention in which:.

<FIG>, <FIG>, <FIG>, <FIG>, and <FIG> schematically show views of a panel <NUM> and/or an electrical end connector <NUM> according to various embodiments of the present invention.

As is shown e.g. in <FIG>, the panel <NUM> is delimited by a first longitudinal side <NUM> and by a second longitudinal side <NUM> being opposite the first longitudinal side <NUM>. The panel <NUM> is also delimited by a first end side <NUM> and by a second end side <NUM> being opposite the first end side <NUM>.

The first longitudinal side <NUM>, the second longitudinal side <NUM>, the first end side <NUM>, and the second end side <NUM> may be provided with panel coupling means, such as a groove/female and tongue/rabbet forming e.g. "click joints" <NUM>, <NUM>, <NUM>, <NUM>, respectively. The panel coupling means <NUM>, <NUM>, <NUM>, <NUM> are, according to an embodiment, arranged in the base layer <NUM> at the first <NUM> and second <NUM> longitudinal sides of the panel, and at the first <NUM> and second <NUM> end sides of the panel, for mechanically coupling the panel <NUM> to at least one adjacent panel <NUM>, <NUM>,. <NUM>, i.e. to at least one other corresponding panel <NUM>, <NUM>,. , <NUM> (as shown in <FIG>), where the at least one other corresponding panel is provided with corresponding panel coupling means, in a known way.

The panel <NUM> further includes a base/core layer <NUM> and a covering/visual layer <NUM>. The covering/visual layer <NUM> has a surface <NUM> possibly being visible from the space to be heated, i.e. from within the room in which the panel covers a floor, wall and/or ceiling. The covering/visual layer may have a suitable appearance/look, including colors and/or patterns.

The panel <NUM> further includes a heat providing layer <NUM> attached to the base layer <NUM>, i.e. arranged between the base layer <NUM> and the covering/visual layer <NUM>. This also means that the heat providing layer is arranged very close to the space to be heated, i.e. directly underneath the thin covering/visual layer <NUM>. The heat providing layer <NUM> may include essentially any material being electrically conducting and having an electrical resistance suitable for creating heat, i.e. an increased temperature, when current flows through the material. The material may be formed as a heat generating element, which may have a large number of shapes. For example, the heat providing layer may comprise printed electronics, a film, one or more resistors, a sheet, a tape, a paint, or may have essentially any other shape or form suitable for creating heat through its electrical resistance and for being included in the panel according to the present invention. Thus, for example, the heat providing layer <NUM> may comprise at least one heat generating element including printed electronics having an electrical resistance, at least one film having an electrical resistance, and/or one or more resistors having an electrical resistance.

As a non-limiting example, it may be mentioned that, when the electric energy has a voltage of <NUM> V, i.e. when the electrical energy providing arrangement delivers a voltage of <NUM> V is used as power supply, <NUM> W/m<NUM> may be created by the heat providing layer according to an embodiment. The time constant for the temperature increase at the covering layer may be short, in the area of minutes, and a temperature increase of e.g. <NUM> may be quickly achieved.

The voltage drop increases with the squared length of the floor. For shorter floors, e.g. floors having a length shorter than <NUM>, the voltage drop has little effect on the created heat. However, for longer floors, e.g. floor longer than <NUM>, the voltage drop may noticeably affect the produced heat.

According to an embodiment of the present invention, the heat providing layer <NUM> is arranged at a heat depth Dheat from the visible surface <NUM> in an interval of <NUM> - <NUM>, <NUM> - <NUM>, or <NUM> - <NUM>, and/or at a depth of <NUM>. This then also means that the covering layer has a thickness Tcov being equal to the heat depth Dheat; Tcov = Dheat; which results in an efficient transport of heat energy into the space to be heated, since the heat providing layer <NUM> is very close to the heated space.

According to an embodiment of the present invention, the layers of the panel <NUM>, i.e. the base layer <NUM>, the heat providing layer <NUM> and the covering layer <NUM> are attached/fixed to each other by use of an adhesive, such as e.g. a glue.

The panel according to the present invention includes a first longitudinal groove <NUM> arranged in parallel with, and having at least a first distance <NUM> to, the first longitudinal side <NUM>, and a and second longitudinal groove <NUM> arranged in parallel with, and having at least a second distance <NUM> to, the second longitudinal side <NUM>. The first <NUM> and second <NUM> longitudinal grooves are arranged in the base layer <NUM> of the panel, and extend from the first end side <NUM> to the second end side <NUM>. The first <NUM> and second <NUM> longitudinal grooves face the heat providing layer <NUM>, i.e. the opening/aperture of the groves are directed towards the heat providing layer <NUM>.

The panel <NUM> according to the present invention further includes at least one electrical end connector <NUM> arranged at one or more of the first <NUM> coupling means at the first end side <NUM>, and the second <NUM> end panel coupling means at the second end side <NUM>, as illustrated e.g. in <FIG>.

The at least one electrical end connector <NUM> includes first <NUM> and second <NUM> end portions that are at least partly electrically conductive, i.e. at least partly include an electrically conducting material, such as e.g. a suitable metal. The first <NUM> and second <NUM> end portions are also at least partly protruding from the one or more of the first <NUM> and second <NUM> end panel coupling means of the panel when being arranged at the one or more of the first <NUM> and second <NUM> end panel coupling means. This makes it possible for the first <NUM> and second <NUM> end portions to provide an electrical connection between the heat providing layer <NUM> of the panel <NUM> and a corresponding heat providing layer of at least one adjacent panel <NUM>, <NUM> coupled to the panel <NUM>. Thus, the first <NUM> and second <NUM> end portions are arranged for making the heat providing layers of at least two adjacent panels <NUM>, <NUM> (shown e.g. in <FIG>) electrically connectable to each other when the panels <NUM>, <NUM>, <NUM> are mechanically coupled to each other.

According to an embodiment of the present invention, schematically illustrated e.g. in <FIG> and <FIG>, the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> are arranged in the at least first <NUM> and second <NUM> longitudinal grooves, respectively.

The at least one electrical end connector <NUM> may here be at least partly resilient and may also include an at least partly protruding portion <NUM> between the first <NUM> and second <NUM> end portions, as is illustrated in <FIG>, <FIG> and <FIG>. Hereby, the at least partly protruding portion <NUM> protrudes at least partly from the one or more of the first <NUM> and second <NUM> end panel coupling means in its relaxed state when the at least one electrical end connector <NUM> is arranged in the at least first <NUM> and second <NUM> longitudinal grooves.

As illustrated e.g. in <FIG> (being a top view of two panels <NUM>, <NUM>) and <FIG> (being views of the second longitudinal sides <NUM> of two panels <NUM>, <NUM>), the at least first <NUM> and second <NUM> longitudinal grooves include, according to an embodiment, first <NUM> and second <NUM> groove end sections adjacent to at least one of the first <NUM> and the second <NUM> end sides, respectively. The first <NUM> and second <NUM> groove end sections are then arranged for at least partly receiving the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM>, respectively.

The first <NUM> and second <NUM> groove end sections may, as illustrated in <FIG>, have a depth Dend being greater than a depth Dmid along a rest of the at least first <NUM> and second <NUM> longitudinal grooves; Dend > Dmid. The end depth Dend may here preferable essentially correspond to a thickness Tend_con of the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> being illustrated schematically in <FIG>. Thus, Dend = Tend_con. The first <NUM> and second <NUM> longitudinal grooves may have the middle depth Dmid except from in the first <NUM> and second <NUM> groove end sections at the ends <NUM>, adjacent to the end sides <NUM>, <NUM>, e.g. in the middle of the length of the first <NUM> and second <NUM> longitudinal grooves. When the end depth Dend corresponds to the thickness Tcon of first <NUM> and second <NUM> end portions, there are no air gaps at the first <NUM> and second <NUM> end sides of the panel. Hereby, a very robust panel is provided. Often, the wear of e.g. flooring panels is worst close to the joints, at the first <NUM> and second <NUM> end sides and/or at the first <NUM> and second <NUM> longitudinal sides, which is mitigated by this embodiment providing robust panel ends.

Also, the first <NUM> and second <NUM> groove end sections may, according to an embodiment, have a length Lend_groove such that the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> protrudes from the one or more of the first <NUM> and second <NUM> end panel coupling means when being received in the first <NUM> and second <NUM> groove end sections, respectively. This is schematically illustrated e.g. in <FIG>.

The first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> are also received, respectively, in corresponding first <NUM> and second <NUM> groove end sections of an adjacent panel <NUM>, <NUM>,. , <NUM> being mechanically coupled to the panel <NUM> by one of the first <NUM> and second <NUM> end panel coupling means. This is schematically illustrated e.g. in <FIG>.

The combined length Lend_groove_comb of the first groove end sections <NUM> and <NUM> of the panel <NUM> and the adjacent panel <NUM> may, according to an embodiment essentially correspond to the length Lend_con of the first <NUM> end portion of the at least one electrical end connector <NUM>. Correspondingly, the combined length Lend_groove _comb of the second groove end sections <NUM> and <NUM> of the panel <NUM> and the adjacent panel <NUM> may, according to an embodiment essentially correspond to the length Lend_con of the second <NUM> end portion of the at least one electrical end connector <NUM>. Hereby, the first <NUM> and second <NUM> end portions essentially exactly fit into the combined length Lend_groove _comb of the groove end sections, whereby a stable and robust electrical connection is provided, as explained more in detail below.

According to an embodiment of the present invention, the lengths Lend_groove of the first groove end sections <NUM> and <NUM> of the panel <NUM> and the adjacent panel <NUM> are different /unequal. Correspondingly, the lengths Lend_groove of the second groove end sections <NUM> and <NUM> of the panel <NUM> and the adjacent panel <NUM>, may be different/unequal, whereby the first <NUM> and second <NUM> end portions are arranged asymmetrically in the joint between the panel <NUM> and the adjacent panel <NUM>, as is schematically illustrated e.g. in <FIG>. The asymmetrical position of the first and second end portions in the joint may be utilized for increasing the stability when coupling panels together.

According to an embodiment of the present invention, the lengths Lend_groove of the first groove end sections <NUM> and <NUM> of the panel <NUM> and the adjacent panel <NUM>, as well as of the second groove end sections <NUM> and <NUM> of the panel <NUM> and the adjacent panel <NUM>, may be essentially equally long, whereby the first <NUM> and second <NUM> portions are arranged symmetrically in the joint between the panel <NUM> and the adjacent panel <NUM>.

The at least one end connector <NUM>, having the first <NUM> and second <NUM> end portions arranged for being inserted into the at least first <NUM> and second <NUM> longitudinal grooves, respectively, is illustrated e.g. in <FIG> and <FIG>.

The at least one end connector <NUM> has the first <NUM> and second <NUM> end portions being connected/attached to each other by an at least partly resilient member <NUM>, e.g. a spring member. The at least one end connector <NUM> may have an at least partly protruding portion <NUM>, which may be formed by the resilient member <NUM> being slightly bent, e.g. by being curve-shaped, arch-shape, v-shaped and/or wave-shaped in its relaxed state. Actually, the at least partly protruding portion <NUM> may essentially have any shape which makes the end connector <NUM> protrude at least partly in its relaxed state from the one or more first <NUM> and second <NUM> end panel coupling means (and/or from their respective end sides <NUM>, <NUM>) where it is arranged. Hereby the at least partly protruding portion <NUM> of the at least one electrical end connector <NUM> is by its shape and/or its resilience arranged for being snapped into at least one of first <NUM> and second <NUM> corresponding end panel coupling means of at least one adjacent panel <NUM>, <NUM>. Hereby, the panel <NUM> is mechanically locked, by snap-fit locking the at least partly protruding portion <NUM> into one or more rims, apertures and/or notches of the corresponding end panel coupling <NUM>, <NUM>, to at least one adjacent panel <NUM>, <NUM>.

When the panels are installed, the end connector <NUM> is fixed, e.g. by being pre-fixed, to one panel <NUM> by insertion of the first <NUM> and second <NUM> end portions into the at least first <NUM> and second <NUM> longitudinal grooves, respectively. The at least partly protruding portion <NUM> then protrudes in its relaxed state from the end panel coupling means where it is fixed. When the panel <NUM> is then mechanically coupled to an adjacent panel <NUM>, by first being tilted and then being pressed down towards the adjacent panel <NUM>, the at least partly protruding portion <NUM> is initially pressed back into its own end panel coupling <NUM>, <NUM> when the panel <NUM> is being pressed down to fit into the corresponding end panel coupling <NUM>, <NUM> of the adjacent panel <NUM>. However, when the end panel coupling <NUM>, <NUM> of the panel <NUM> and the corresponding end panel coupling <NUM>, <NUM> of the adjacent panel <NUM> have been fit together, the end connector <NUM> once again returns to its relaxed stat shape by snapping out into the one or more rims, apertures and/or notches of the corresponding end panel coupling <NUM>, <NUM> of the adjacent panel <NUM>, which helps the panel <NUM> and the adjacent panel <NUM> to be mechanically fixed to each other.

Also, when the panel <NUM> and the adjacent panel <NUM> are attached to each other in this way, the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> are initially inserted/received into the first <NUM> and second <NUM> groove end sections of the panel <NUM>. Then, when the panel <NUM> is pressed down to be fitted into the corresponding end panel coupling <NUM>, <NUM> of the adjacent panel <NUM>, the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> are also inserted/received into the corresponding first <NUM> and second <NUM> groove end sections of the adjacent panel <NUM> being coupled to the panel <NUM>.

As described more in detail below, the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> are at least partly electrically conductive, which facilitates an electrical connection between the panel <NUM> and the adjacent panel <NUM>, i.e. between the heat providing layers of the panel <NUM> and the adjacent panel <NUM>. The first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> may for this reason include first <NUM> and second <NUM> electrically conducting tongues, respectively, as illustrated in e.g. <FIG> and <FIG>. The tongues <NUM>, <NUM> are arranged for being in electrical contact with the heat providing layers <NUM> of the panel <NUM> and of the adjacent panel <NUM> being coupled together.

<FIG> shows an end side view of a part of the panel <NUM>. The end panel coupling means <NUM> are arranged at the end side <NUM>. It is here also illustrated how the second end portion <NUM> of the electrical end connector <NUM> is arranged/received/inserted in the second <NUM> groove end section of the second <NUM> longitudinal groove close to the second longitudinal side <NUM>. Correspondingly (although not shown), the first end portion <NUM> of the electrical end connector is arranged/received/inserted in the first <NUM> groove end section of the first <NUM> longitudinal groove close to the first longitudinal side <NUM>.

<FIG> show two views of one part of the electrical end connector <NUM>, including the second end portion <NUM>, and the electrically connecting tongue <NUM> being attached to the end portion <NUM> e.g. by a nail (shown), by soldering (not shown) and/or by an adhesive (not shown). The electrical end connector <NUM> also includes a resilient member <NUM>. As described herein, the electrical end connector <NUM> further includes the first end portion <NUM> on the other end of the protruding portion <NUM> (not shown).

According to an embodiment of the present invention, not both of the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> are arranged in the first <NUM> and second <NUM> longitudinal grooves of the panel, i.e. one or more of the first <NUM> and second <NUM> end portions are arranged in recesses separate from the first <NUM> and second <NUM> longitudinal grooves.

As illustrated in the end side view <FIG>, the panel <NUM> then includes first <NUM> and second <NUM> panel end recesses adjacent to/facing at least one of the first <NUM> and the second <NUM> end sides, respectively, i.e. adjacent to/facing the at least one of the first <NUM> and second <NUM> end panel coupling means. The first <NUM> and second <NUM> panel end recesses have at least first <NUM> and second <NUM> distances to the first <NUM> and second <NUM> longitudinal sides, respectively, and being arranged for at least partly receiving the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM>. At least one of the first <NUM> and second <NUM> end recesses are located further from its respective first <NUM> and second <NUM> longitudinal sides than the corresponding herein described first <NUM> and second <NUM> longitudinal groove. Thus, at least one of the first <NUM> and second <NUM> longitudinal side distances for the first <NUM> and second <NUM> panel end recesses is longer than the corresponding first <NUM> and second <NUM> longitudinal side distances for the first <NUM> and second <NUM> grooves, respectively; <NUM> > <NUM> and/or <NUM> > <NUM>.

The first <NUM> and second <NUM> panel end recesses are similar to the above described first <NUM> and second <NUM> groove end sections, although being arranged at other first <NUM> and second <NUM> longitudinal side distances than the above mentioned first <NUM> and second <NUM> longitudinal side distances of the first <NUM> and second <NUM> groove end sections, respectively.

Thus, according to an embodiment, the first <NUM> and second <NUM> panel end recesses have a depth Dend essentially corresponding to a thickness Tend_con for the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM>; Dend = Tend_con. the first <NUM> and second <NUM> panel end recesses may have a depth Dend being greater than a depth Dmid along a rest of the at least first <NUM> and second <NUM> longitudinal grooves; Dend > Dmid. When the end depth Dend corresponds to the thickness Tend_con of the first <NUM> and second <NUM> end portions of the at least one electrical end connector, there are no air gaps at the first <NUM> and second <NUM> end sides of the panel. Hereby, a very robust panel is provided, for which wear of the joints is mitigated.

The first <NUM> and second <NUM> panel end recesses may further, according to an embodiment, have a length Lend_recess such that the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> protrudes from the one or more of the first <NUM> and second <NUM> end panel coupling means when being received in the first <NUM> and second <NUM> panel end recesses, respectively.

The first <NUM> and second <NUM> panel end recesses may, according to an embodiment, further include a supporting notch/rim/aperture <NUM> arranged for receiving a supporting member <NUM> of the electrical end connector <NUM>, as described more in detail below.

The first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> are then received, respectively, in corresponding first and second panel end recesses of an adjacent panel <NUM>, <NUM> being mechanically coupled to the panel <NUM>, whereby the first <NUM> and second <NUM> end portions may be symmetrically or asymmetrically arranged in the joints between two adjacent panels <NUM>, <NUM>, as described above.

As shown in <FIG>, for the embodiments in which the panel <NUM> includes the first <NUM> and second <NUM> panel end recesses, the at least one electrical end connector <NUM> may include a supporting member <NUM> attached to the first <NUM> and second <NUM> end portions, i.e. arranged on a bridging member <NUM> arranged/attached between first <NUM> and second <NUM> end portions. The supporting member <NUM>, illustrated in different views in <FIG>, protrudes from the one or more of the first <NUM> and second <NUM> end panel coupling means when it is received/arranged in the first <NUM> and second <NUM> panel end recesses. The supporting member <NUM> is arranged for being inserted into the supporting notch/rim/aperture <NUM> of an adjacent panel <NUM> being coupled to the panel <NUM>, thereby creating a force F acting against a torque Tq provided to the panel <NUM> when the panel <NUM> is pressed down for being mechanical coupled to the adjacent panel <NUM> by the end panel coupling means. Thus, the supporting member <NUM> of the panel <NUM> is arranged for, in cooperation with the supporting notch/rim/aperture <NUM> of an adjacent panel <NUM>, creating the stabilizing force F in response to the pressing torque Tq, which facilitates a safe mechanical coupling of the panel <NUM> and the adjacent panel <NUM>.

The supporting member <NUM> is, according to an embodiment, at least partly tapered, i.e. has an at least partly tapered portion/section <NUM>, which facilitates easier insertion of the supporting member <NUM> into the supporting notch/rim/aperture <NUM>. The supporting member <NUM> may have essentially any form suitable for creating the stabilizing anti-torque force F, and may e.g. have the form of at least one plug and/or pin, as illustrated in <FIG>, whereby the supporting notch/rim/aperture <NUM> includes at least one corresponding hole, as illustrated in <FIG>, against which the force F may act. The supporting member <NUM> may also have the form of a lip, which may more or less be extended along the end side of the panel <NUM>, whereby the supporting notch/rim/aperture <NUM> includes a corresponding edge, against which the stabilizing force F may act.

As described above and below, the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> are at least partly electrically conductive, which facilitates an electrical connection between the panel <NUM> and the adjacent panel <NUM>, i.e. between the heat providing layers of the panel <NUM> and the adjacent panel <NUM>. The first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> may for this reason include first <NUM> and second <NUM> electrically conducting tongues, respectively, as illustrated in <FIG>. The tongues <NUM>, <NUM> are arranged for being in electrical contact with the heat providing layers <NUM> of the panel <NUM> and of the adjacent panel <NUM> being coupled together.

The first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> may also be made of an electrically conducting material themselves to provide the electrical connection.

The first <NUM> and second <NUM> end portions of the electrical end connector <NUM> are arranged/received/inserted in the first <NUM> and second <NUM> end recesses in the panel <NUM>, and in corresponding first and second end recesses of an adjacent panel <NUM> being coupled mechanically to the panel <NUM>. Hereby, the electrical connection between the panel <NUM> and the adjacent panel <NUM>, i.e. between the heat providing layers of the panel <NUM> and the adjacent panel <NUM> is achieved/provided, as described herein.

According to an embodiment, an electrical coupling is arranged from the first <NUM> and second <NUM> end portions received in the first <NUM> and second <NUM> end recesses to the first <NUM> and second <NUM> longitudinal coupling elements in the panel <NUM>, as described in detail for the first <NUM> and second <NUM> longitudinal coupling elements.

As illustrated in <FIG>, one or more of the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> may, according to an embodiment, be at least partly resilient, e.g. may have a resilient/flexible member <NUM> which is arranged for snap locking with at least one of at least one corresponding first <NUM> and second <NUM> end panel coupling means of at least one adjacent panel <NUM>, <NUM>. The resilient member <NUM> is then pressed against the one or more end portion <NUM> (in the example shown in <FIG>) when being inserted into one or more of the first <NUM> and second <NUM> end recesses, and then flexes out/away from the one or more end portion <NUM> and extends/snaps into an aperture/notch/rim of the adjacent panel <NUM>, <NUM>, when the panel <NUM> and the adjacent panel <NUM>, <NUM> are mechanically coupled together, thereby providing the snap locking function. The panel <NUM> may here be provided with a through hole from one or more of the first <NUM> and second <NUM> longitudinal sides to one or more of the first <NUM> and second <NUM> end recesses, such that an instrument, e.g. a screwdriver or the like, may be inserted into the through hole and may be pressed against the resilient member <NUM> to unlock/release the snap locking.

According to an embodiment, a first longitudinal coupling element <NUM> is arranged in the first longitudinal groove <NUM>, and a second longitudinal coupling element <NUM> is arranged in the second longitudinal groove <NUM>. The first <NUM> and second <NUM> longitudinal coupling elements then extend in the first <NUM> and second <NUM> longitudinal grooves, respectively, from the first end side <NUM> to the second end side <NUM>, i.e. along essentially the whole length of the panel.

<FIG> and <FIG> schematically show cross-sectional views of a part of the panel <NUM> including the first longitudinal groove <NUM> formed in the base layer <NUM> of the panel at the first distance <NUM> to the first longitudinal side <NUM>. The heat providing layer <NUM> is attached to the base layer <NUM>, and the covering layer <NUM> is attached to the heat providing layer <NUM>.

According to an embodiment of the present invention, the first <NUM> and second <NUM> surfaces of the first <NUM> and second <NUM> longitudinal coupling elements facing the heat providing layer <NUM> are, when the panel <NUM> is assembled, aligned with the rest of the surface <NUM> of the base layer <NUM>. Thus, the surface <NUM> of the base layer <NUM> outside of the first <NUM> and second <NUM> longitudinal grooves and the first <NUM> and second <NUM> surfaces of the first <NUM> and second <NUM> longitudinal coupling elements, respectively, are on the same level, such that an essentially flat common surface <NUM>, <NUM>, <NUM> facing the heat providing layer <NUM> is created by the base layer <NUM> and the first <NUM> and second <NUM> longitudinal coupling elements. Hereby, a very robust panel is achieved, which copes with essentially all sorts of pressure on the covering layer <NUM>.

According to an embodiment, schematically illustrated in <FIG>, the first <NUM> and second <NUM> longitudinal coupling elements comprise an at least partly resilient and electrically conducting material, such as e.g. an electrically conducting metal. These first <NUM> and second <NUM> longitudinal coupling elements may then by this resilience create a pressing force against the side and/or bottom walls of the first <NUM> and second <NUM> longitudinal grooves, which securely fixates the first <NUM> and second <NUM> longitudinal coupling elements within the first <NUM> and second <NUM> longitudinal grooves. The first <NUM> and second <NUM> longitudinal coupling elements may for example be essentially U-shaped, and may be inserted upside-down in the first <NUM> and second <NUM> longitudinal grooves while the legs of the U-shaped elements are pressed together, whereby a spring force towards the inside walls of the first <NUM> and second <NUM> longitudinal grooves is created.

According to another embodiment of the present invention, schematically illustrated in <FIG>, the first <NUM> and second <NUM> longitudinal coupling elements comprise a solid and electrically conducting material, such as e.g. an electrically conducting metal.

The first <NUM> and at second <NUM> electrical end connectors, e.g. the first <NUM> and second <NUM> electrically conducting tongues of the first <NUM> and at second <NUM> electrical end connectors, may then for the embodiments shown in <FIG> and <FIG>, be electrically connected to the heat providing layer <NUM> by being arranged in the first <NUM> and second <NUM> longitudinal grooves, e.g. in the first <NUM> and second <NUM> groove end sections. The electrical connection may be provided via the electrically conducting at least first <NUM> and second <NUM> longitudinal coupling elements. The heat providing layer <NUM> may here be arranged between the covering layer <NUM> and the first <NUM> and second <NUM> longitudinal coupling elements, as shown in <FIG> and <FIG>. The heat providing layer <NUM> may be attached to the first <NUM> and second <NUM> longitudinal coupling elements, e.g. by an electrically conducting adhesive and/or an electrically conducting soldering. The first <NUM> and second <NUM> electrical end connectors and/or the first <NUM> and second <NUM> electrical power supply end connectors may here be arranged between the bottom of the first <NUM> and second <NUM> longitudinal grooves and the first <NUM> and second <NUM> longitudinal coupling elements. Thus, the first <NUM> and second <NUM> electrical end connectors, e.g. the first <NUM> and second <NUM> electrically conducting tongues of the first <NUM> and at second <NUM> electrical end connectors, may be fixed in the panel <NUM> by being pressed against the bottom of the first <NUM> and second <NUM> longitudinal grooves by the first <NUM> and second <NUM> longitudinal coupling elements.

According to an embodiment, schematically illustrated in <FIG>, the heat providing layer <NUM> is arranged on the surface <NUM> of the base layer <NUM> outside of the first <NUM> and second <NUM> longitudinal grooves and in the first <NUM> and second <NUM> longitudinal grooves between the base layer <NUM> and the first <NUM> and second <NUM> longitudinal coupling elements, respectively. The first <NUM> and second <NUM> longitudinal coupling elements may here be either electrically nonconducting, e.g. of an electrically isolating material such as wood or a plastic material, or may be electrically conducting, e.g. of a metal. The primary function of the first <NUM> and second <NUM> longitudinal coupling elements is here to press the heat providing layer <NUM> against the first <NUM> and second <NUM> electrical end connectors, e.g. against the first <NUM> and second <NUM> electrically conducting tongues of the first <NUM> and at second <NUM> electrical end connectors, and/or against the below described first <NUM> and second <NUM> electrical power supply end connectors being inserted/arranged into the first <NUM> and second <NUM> longitudinal grooves, such that an electrical contact/connection between the heat providing layer <NUM> and the first <NUM> and second <NUM> electrical end connectors, e.g. the first <NUM> and second <NUM> electrically conducting tongues of the first <NUM> and at second <NUM> electrical end connectors, is secured.

Also, the U-shaped and at least partly resilient first <NUM> and second <NUM> longitudinal coupling elements illustrated in <FIG> may also be arranged such that the heat providing layer <NUM> is arranged in the first <NUM> and second <NUM> longitudinal grooves between the base layer <NUM> and the first <NUM> and second <NUM> longitudinal coupling elements, respectively. Thus, the heat providing layer <NUM> would then be arranged in the first <NUM> and second <NUM> longitudinal grooves with the first <NUM> and second <NUM> longitudinal coupling elements inserted in the grooves on top of the heat providing layer <NUM>, and on the surface <NUM> of the base layer <NUM> outside of the first <NUM> and second <NUM> longitudinal grooves. The legs of the U-shaped elements may then be pressed together at insertion into the grooves, whereby a spring force at least towards the inside walls of the first <NUM> and second <NUM> longitudinal grooves is created after insertion. This also results in that the first <NUM> and second <NUM> longitudinal coupling elements and the heat providing layer <NUM> are pressed firmly against each other, resulting in a reliable electrical contact between the two, at the same time as the wear on the heat providing layer <NUM> is minimized.

The panel <NUM> may, according to some embodiments of the present invention, include further longitudinal grooves, i.e. may in total include more than two longitudinal grooves. The panel then also includes further corresponding longitudinal coupling elements, and further corresponding electrical end connectors.

<FIG> illustrate an embodiment of the present invention, in which the panel <NUM> includes at least one sandwich/isolating core <NUM> included in the base layer <NUM>. The at least one sandwich/isolating core <NUM> may have heat insulating properties, preventing that created heat is transported in the wrong direction, i.e. away from the space to be heated. For example, a temperature increase of e.g. <NUM> for a panel without insulation could result in a temperature increase of e.g. <NUM>-<NUM> for the same panel with at least one sandwich/insulating core <NUM> added to the base layer <NUM>. The at least one sandwich/insulating core <NUM> may also have sound/noise absorbing properties, which then efficiently reduces the noise of e.g. high heels being walked across the floor.

The sandwich/isolating core <NUM> may e.g. include polyurethane, for example in form of a polyurethane foam being injected at and/or after assembly of the layers of the panel <NUM>.

<FIG> illustrate some embodiments of the present invention, in which the panel <NUM> includes at least one sandwich/insulating core <NUM> included in the base layer <NUM>. The at least one sandwich/insulating core <NUM> may here e.g. include pyramid formed support elements E that may, by the side surfaces A, B of the pyramid forms, provide supportive force/pressure from the pyramid formed support elements E on the corresponding pyramid formed parts D of the base layer <NUM> of the panel <NUM>, such that they may carry heavier loads. The pyramid formed support elements E may have their base side facing away from the covering layer <NUM>, and the pointed side towards the covering layer <NUM>. As mentioned above, the at least one sandwich/insulating core <NUM> may have heat and/or sound/noise insulating properties. Thus, the pyramid shaped support elements provide optimal insulation in combination with an optimal carrying capacity for the panel <NUM>.

<FIG> illustrate an embodiment, for which load/weight carrying element <NUM> are arranged between the sandwich/insulating core pyramid forms <NUM> in the base layer <NUM> material, which may be e.g. wood or some other material suitable for carrying weight. The load carrying element <NUM> may for example have a circular form, e.g. may be essentially screw/bolt-formed with a wider circular head part and a thinner circular pointed part, with the wider part directed towards the covering layer <NUM>. The load carrying element <NUM> may be of essentially any load carrying material, such as e.g. metal or plastic. The circular head part of the load carrying element <NUM> is arranged for carrying weight/load originating from the covering layer <NUM>, such that the bottom regions of the pyramid formed parts D of the base layer <NUM> may be less strong, i.e. do not have to be strong enough to itself take up the whole carrying weight/load. Thus, the weight/load originating from the covering layer is here at least partly carried by the load carrying elements <NUM>.

The load carrying elements <NUM> may be casted/moulded together with base layer <NUM> material in order to improve the load carrying capabilities of the panel, i.e. to improve the load/weight carrying capabilities of the base layer <NUM> material. Hereby, a less stable and more porous material may be used for the rest of the base layer <NUM> material, which lowers the production costs.

According to an aspect of the present invention, an electrical end connector <NUM> is presented. The electrical end connector <NUM> and its embodiments are described in this document, and is illustrated e.g. in <FIG> and <FIG>. The electrical end connector <NUM> is insertable into one or more of the first <NUM> and second <NUM> end panel coupling means of the herein described panel <NUM>, according to the herein described embodiments.

The electrical end connector <NUM> includes the first <NUM> and second <NUM> end portions, being at least partly electrically conductive and at least partly protruding from the one or more of the first <NUM> and second <NUM> end panel coupling means when being inserted into one or more of the first <NUM> and second <NUM> end panel coupling means. The electrical end connector <NUM> thereby provides an electrical connection between the heat providing layer <NUM> of the panel <NUM> and a corresponding heat providing layer of at least one adjacent panel <NUM>, <NUM> coupled to the panel.

More in detail, when the panel and an adjacent panel are mechanically coupled together, the first and second end portions of the electrical end connector are, according to various embodiments, inserted/received in first and second groove end sections and/or panel end recesses of both the panel and the adjacent panel, whereby the at least partly conducting first and second end portions provides for the electrical connection between the heat providing layers of the panel and of the adjacent panel.

According to an embodiment, the electrical end connector also provides a mechanical coupling to at least one adjacent panel, e.g. by snap locking.

As mentioned above, and also being illustrated e.g. in <FIG> and <FIG>, the first <NUM> and second <NUM> end portions of the at least one electrical end connector <NUM> may, according to an embodiment, include first <NUM> and second <NUM> electrically conducting tongues, respectively. The first <NUM> and second <NUM> electrically conducting tongues are arranged for being in electrical contact with the heat providing layer <NUM> of the panel <NUM> and with a corresponding heat providing layer <NUM> of an adjacent panel <NUM>, <NUM>, when the panel <NUM> is coupled to an adjacent panel <NUM>, <NUM>.

For embodiments where at least first <NUM> and second <NUM> longitudinal coupling elements are used, as described above, the first <NUM> and second <NUM> end portions, e.g. the first <NUM> and second <NUM> electrically conducting tongues of the first <NUM> and second <NUM> end portions, may be arranged for being in electrical contact with at least first <NUM> and second <NUM> longitudinal coupling elements arranged in the at least first <NUM> and second <NUM> longitudinal grooves, respectively, of the panel <NUM>. The first <NUM> and second <NUM> electrically conducting tongues are then also in electrical contact with a corresponding at least first <NUM> and second <NUM> longitudinal coupling elements of an adjacent panel <NUM>, <NUM> being mechanically coupled to the panel <NUM>.

According to an embodiment, the first <NUM> and second <NUM> electrically conducting tongues have a form being suitable for creating a solid contact with the heat providing layers <NUM> and/or with the at least first <NUM> and second <NUM> longitudinal coupling elements. The first <NUM> and second <NUM> electrically conducting tongues may for example be at least partly wave-formed, with the peaks of the wave form pointing towards the heat providing layers and/or the least first <NUM> and second <NUM> longitudinal coupling elements.

The electric energy being conveyed to the heat providing layer by the first <NUM> and second <NUM> electrical end connectors, and possibly the first <NUM> and second <NUM> longitudinal electrical coupling elements, may have a voltage in the interval of <NUM> Volts - <NUM> Volts, or in the interval of <NUM> Volts - <NUM> Volts, or in the interval of <NUM> Volts - <NUM> Volts, or in the interval of <NUM> Volts - <NUM> Volts. The panel according to the present invention may be supplied with such low voltages since the electrical contact between adjacent panels, and possibly also the current/voltage conducting characteristics of the first and second longitudinal electrical coupling elements, and therefore of the panel itself, are very good, i.e. have low losses.

According to an example embodiment of the present invention, the electric energy being supplied to the heat providing layer <NUM> in order to create the heat has a voltage V of <NUM> Volts; V = <NUM> volt, which in many regions and/or countries may be handled by a layman, i.e. by a non-electrician.

According to another example embodiment of the present invention, the electric energy has a voltage V of <NUM> Volts; V = <NUM> volt, which in some regions and/or countries may be handled by a layman.

According to an aspect of the present invention, a heating system <NUM> is presented. The heating system <NUM>, is schematically illustrated in <FIG>, and includes at least one panel <NUM>, <NUM> as described above. The heating system further includes an electrical energy providing arrangement <NUM>, arranged e.g. at a mounting base <NUM> and/or facing the base layer <NUM> adjacent to at least one of the first <NUM> and the second <NUM> end sides of the at least one panel <NUM>, <NUM>. The electrical energy providing arrangement <NUM> supplies the electric energy to the first <NUM> and second <NUM> electrical power supply end connectors of the panel <NUM>. In <FIG>, only two panels <NUM>, <NUM> are shown for simplicity. As is clear for a skilled person, many more panels may be included in the heating system <NUM>. Also, each one of the panels <NUM>, <NUM> in <FIG> may represent a row of panels. It should be noted that the electrical energy providing arrangement <NUM> described in this document may be used for supplying electrical energy to essentially any electrically heated panel, i.e. not only to the herein described panel <NUM>.

According to the embodiment shown in <FIG>, the electrical energy is provided by first and second polarities P1, P2 being supplied to the first <NUM> and second <NUM> electrical power supply end connectors of the first end side <NUM> of the panel <NUM>, or to a corresponding first end side <NUM>' of an adjacent panel <NUM> coupled directly or indirectly to the first end side <NUM> of the panel <NUM>. Thus, both the first and second polarities P1, P2 are connected to a first end side <NUM> of a first panel <NUM>, <NUM> in each row of panels being coupled together at their end sides <NUM>, <NUM>. The first and second polarities P1, P2 are then electrically connected to further panels in each row of panels, laid as illustrated in <FIG>, such that all panels of the whole floor/wall/ceiling are electrified. Hereby, the whole area covered by the panels is heated. Since the voltage used in <FIG> is rather low, e.g. <NUM> Volts, both of the first and second polarities P1, P2 may be supplied to the same end side <NUM> of the panel. This is possible since the risk for a dangerous electric shock of a person installing the panels is essentially non-existing at these low voltages.

According to another embodiment of the present invention, the electric energy has a voltage of <NUM> Volts; V = <NUM> Volts; which in some regions and/or countries may be handled by a layman, i.e. by a non-electrician. A heating system <NUM> is schematically illustrated in <FIG>, which includes at least one panel <NUM>, <NUM>, <NUM> as described above. The heating system further includes an electrical energy providing arrangement <NUM>, arranged e.g. at a mounting base <NUM> and/or facing the base layer <NUM>, on two opposite sides of a floor, wall or ceiling, and adjacent to at both the first <NUM> and the second <NUM> end sides of the at least one panel <NUM>, <NUM>, <NUM>. It should be noted that the electrical energy providing arrangement <NUM> described in this document may be used for supplying electrical energy to essentially any electrically heated panel, i.e. not only to the herein described panel <NUM>.

The electrical energy providing arrangement <NUM> may include contact means <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, each one being arranged for providing one polarity P1, P2 to the panel <NUM>, <NUM>, <NUM> by use of a contact protrusion <NUM> and/or first <NUM> and second <NUM> electrical power supply end connectors. The contact means <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and/or the panels <NUM>, <NUM>, <NUM> may also include a stability protrusion <NUM>.

When the contact means <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are assembled with, i.e. are inserted into, the panels <NUM>, <NUM>, <NUM>, the electrical energy is provided to the panels <NUM>, <NUM>, <NUM> by the contact protrusions <NUM>, and the panels <NUM>, <NUM>, <NUM> are held in place by the stability protrusions <NUM>. Also, the electrical energy, i.e. the voltage creating the heat in the panels <NUM>, <NUM>, <NUM>, is encapsulated within the panels <NUM>, <NUM>, <NUM> by the contact means <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The risk for getting an electric shock is therefore minimized for the heating system <NUM> illustrated in <FIG>, partly due to the encapsulated electrical energy, and partly because the two polarities P1, P2 are provided to opposite sides of a floor, wall or ceiling being covered by the panels, and are therefore difficult, often impossible, for a person to come in physical contact with both of P1 and P2 at the same time.

Also, the voltage drop over the heat providing layer is approximately reduced by <NUM> % when the two polarities P1, P2 are provided to opposite sides of a floor.

According to an embodiment of the present invention, schematically illustrated in <FIG>, the electrical energy is thus provided to the panel <NUM> by the first polarity P1 being supplied to the first <NUM> or second <NUM> electrical power supply end connectors of the first end side <NUM> of a panel <NUM>. The second polarity P2 is then supplied to the first <NUM> or second <NUM> electrical end connectors of the second end side <NUM> of the panel. Thus, the first polarity P1 is supplied to one end side <NUM> of the panel <NUM>, and the second polarity P2 is supplied to the opposite end side <NUM> of the panel <NUM>.

Also, the second polarity P2 may be supplied to the first <NUM> or second <NUM> electrical power supply end connectors of a corresponding first end side <NUM>' of an adjacent panel <NUM> coupled directly or indirectly to the first end side <NUM> of the panel <NUM>, as illustrated in <FIG>. Also, the second polarity P2 may be supplied to the first <NUM> or second <NUM> electrical power supply end connectors of a corresponding second end side <NUM>' of an adjacent panel <NUM> coupled directly or indirectly to the second end side <NUM> of the panel <NUM>.

The electrical energy providing arrangement <NUM> thus supplies the electric energy to the first <NUM> and second <NUM> electrical power supply end connectors on two opposite end sides of the at least one panel <NUM>, <NUM>, <NUM>. In <FIG>, only three panels <NUM>, <NUM>, <NUM> are shown for simplicity. As is clear for a skilled person, however, many more panels may be included in the heating system <NUM>. Also, each one of the panels <NUM>, <NUM>, <NUM> in <FIG> may represent a row of panels.

<FIG> schematically illustrates a complete heating system is illustrated.

As illustrated in <FIG>, and mentioned above, first <NUM> and second <NUM> electrical power supply end connectors, may be used on one end side <NUM> of the panel, if this end side is the end side starting a row of panels, i.e. is the end side facing a wall, socket or the like from which the electrical power is provided to the row of panels. These first <NUM> and second <NUM> electrical power supply end connectors may be essentially any kind of connector/terminal creating a solid electrical connection, such as e.g. a connector being at least partly resilient and slightly tilted vertically, for example in an upward direction, as illustrated in <FIG>, providing a connection force between the first <NUM> and second <NUM> electrical power supply end connectors and a contact means <NUM> of an electrical energy providing arrangement <NUM> including e.g. a mounting base <NUM> arranged for example along at least one wall on at least one side of a floor, wall or ceiling, and adjacent to the end side of the at least one panel <NUM>.

The at least one first contact means <NUM> may here e.g. be arranged as an electrically conducting contact strip, possibly in metal, being arranged horizontally in the electrical energy providing arrangement <NUM>, such that it provides for a contact surface for the slightly upwardly tilted first <NUM> and second <NUM> electrical power supply end connectors. Thus, a vertical contact force Fcon is created when the at least one panel <NUM> and the electrical energy providing arrangement <NUM>, e.g. in the form of a mounting base, are mounted together.

Also, the electrical energy providing arrangement <NUM>, e.g. included in the mounting base <NUM> described in this document may, as mentioned above, be used for supplying electrical energy to essentially any electrically heated panel, i.e. not only to the herein described panel <NUM>, and/or to any other electrical energy consuming device <NUM>, such as e.g. a wall or ceiling heating panel, a lamp or the like. The electrical energy providing arrangement <NUM> may for this reason include at least one second contact means <NUM>.

According to an embodiment, the at least one first contact means <NUM> may be provided with first polarity P1, and the at least one second contact means <NUM> may be provided with another second polarity P2.

Hereby, electrical energy may by the electrical energy providing arrangement <NUM> supply electrical energy to essentially any electrical device <NUM> driven by the voltage provided by the electrical energy providing arrangement <NUM>. For example, many kinds of lamps are driven by lower voltages, such as e.g. <NUM> Volt or <NUM> Volt, and may therefore be directly supplied with this voltage from the electrical energy providing arrangement <NUM>.

Also, the at least one first <NUM> and the at least one second <NUM> contact means of adjacent parts of the energy providing arrangement <NUM>, e.g. in the form of adjacent mounting base parts mounted together, may be electrically coupled by means of coupling means <NUM>, <NUM>, e.g. in form of sheet metal, that may possibly correspond in form and/or function to the herein described first <NUM> and second <NUM> electrical end connectors.

In <FIG>, a heating system according to an embodiment is illustrated. The electrical energy providing arrangement <NUM> is here located underneath the panel <NUM>, i.e. facing the base layer <NUM> of the panel. The at least one first <NUM> and at least one second <NUM> electrical power supply end connectors are then bent around at least one of the first <NUM>, <NUM>' and the second <NUM>, <NUM>' end sides of the panel, and are arranged between the base layer <NUM> of the panel <NUM> and the electrical energy providing arrangement <NUM>. Hereby, the at least one first <NUM> and at least one second <NUM> electrical power supply end connectors are pressed against, and are thus in electrical contact with, at least one part of the electrical energy providing arrangement <NUM>. The electrical energy providing arrangement <NUM> may, according to an embodiment, include at least one adhesive tape comprising an electrically conducting element <NUM> facing the base layer <NUM> of the panel <NUM>. The adhesive tape may for example be pasted/arranged on a floor adjacent to a wall, and thus also adjacent to a panel end side <NUM>, in order to create contact with the at least one first <NUM> and at least one second <NUM> electrical power supply end connectors. On the rest of the floor, i.e. underneath the rest of the panels, a stepping layer <NUM>, being e.g. a thin foam and/or paper layer, may cover the floor.

According to an embodiment of the present invention, a method for installing the heating system <NUM> is presented
When panels according to the present invention are to be assembled/laid to become e.g. a floor, the electrical energy providing arrangement <NUM>, <NUM> described above may first be arranged/mounted at a mounting base <NUM>, <NUM> and/or facing the base layer <NUM> on one or two sides of the room to be floored. For example, a lower voltage energy providing arrangement, providing e.g. <NUM> Volts may be arranged/mounted along one wall of a room and then provides both polarities P1, P2 of the voltage. A higher voltage energy providing arrangement, providing e.g. <NUM> Volts, may instead be arranged along two opposite sides of a room and the provides one polarity of the voltage from each opposite side of the room. Thus, the electrical energy is then available at one or two sides of the room.

A first panel <NUM> is then mechanically coupled to at least one second panel <NUM>, <NUM> by use of the mechanical coupling means <NUM>, <NUM> on the first <NUM> and second <NUM> end sides. Hereby, a row of two or more panels <NUM>, <NUM>, <NUM> is created. The last second panel <NUM> in such a row of panels may have to be cut such that the length of the row corresponds to the length of the room.

At the same time as the panels of the row are mechanically coupled, an electrical connection of the first panel <NUM> and the at least one second panel <NUM>, <NUM> is achieved by the at least one end connector <NUM> of the first panel <NUM>. Thus, as the panels <NUM>, <NUM>, <NUM> are pressed together by the mechanical coupling means <NUM>, <NUM>, also the at least one end connector <NUM>, i.e. the first <NUM> and second <NUM> of the end portions of at least one end connector <NUM>,of the panels <NUM>, <NUM>, <NUM> of the row are pressed into the first <NUM>, <NUM> and second <NUM>, <NUM> groove end sections and/or into the first <NUM> and second <NUM> panel end recesses of the panels <NUM>, <NUM>, <NUM>, thereby causing an electrical connection of the heat providing layers <NUM> of the panels <NUM>, <NUM>, <NUM>, e.g. by use of the first <NUM> and second <NUM> longitudinal electrical coupling elements of the panels <NUM>, <NUM>, <NUM> in the row.

Then, the row of the first panel <NUM> and the at least one second panel <NUM>, <NUM> is supplied with electrical energy from the electrical energy providing arrangement <NUM>, <NUM>. According to an embodiment described above, which is useful e.g. for lower voltages, this is done by connecting both of the first <NUM> and second <NUM> electrical power supply end connectors of the first panel <NUM> to the electrical energy providing arrangement <NUM>, <NUM>, which then supplies both of the voltage polarities P1, P2 to the first end side <NUM> of the first panel <NUM>.

According to another embodiment described above, which is useful e.g. for higher voltages, the row of the first panel <NUM> and the at least one second panel <NUM>, <NUM> is supplied with electrical energy from the electrical energy providing arrangement <NUM>, <NUM> by connecting one of the first <NUM> and second <NUM> electrical power supply end connectors on the first end side <NUM> of the first panel <NUM> to the electrical energy providing arrangement <NUM>, <NUM>. The electrical energy providing arrangement <NUM>, <NUM> then provides the first side <NUM> of the first panel <NUM> of the row of panels with one polarity P1 of the electrical energy. Then, another one of the first <NUM> and second <NUM> electrical power supply end connectors on the second end side <NUM>' of the row, i.e. on the second side <NUM>' of the at least one second panel <NUM>, <NUM> is connected to the electrical energy providing arrangement <NUM>, <NUM>. The electrical energy providing arrangement <NUM>, <NUM> then provides the second side <NUM>' of the row with another polarity P2 of the electrical energy.

As mentioned above, to supply the row of panels <NUM>, <NUM>, <NUM> with one voltage polarity at each end of the row has an advantage in that the risk for a person laying the floor getting an electric shock by the electric energy being provided to the panels is considerably reduced. In order to get an electric shock, i.e. in order to come in contact with both polarities of the voltage, the person would have to reach across the entire room, along the whole length of the row of panels, which is not very likely. Thus, a higher voltage supply may be used with this embodiment of the invention.

In the following, some non-limiting examples descriptions of electrical properties and heating properties of a floor according to some of the herein described embodiments are presented.

A power consumption for the floor, P, is given as: <MAT> where U is the voltage applied on the heat providing layer, and I is the corresponding applied electrical current. The applied voltage U is given by the voltage Usupply provided by the power source minus a voltage drop ΔU between the power source and the heat providing layer, i.e.: <MAT>.

The current I flowing through the heat providing layer is given by ohm's law: <MAT> <MAT> where R is the resistance of the heat providing layer. The heat providing layer may be divided in heating modules/sections, where a multiple of modules/sections may be coupled in parallel. For one heat module/section the resistance is given by: <MAT> where the resistivity is a material parameter, e.g. for pure aluminum approximately <NUM> × <NUM>-<NUM> ohm m, Lc_heat is the length of the heating conductor (resistor), and Ac_heat is the cross section area of the heating conductor. The cross section area of the conductor Ac_heat is e.g. for a thin film given as: <MAT> where hc_heat is the height/thickness of the conductor (resistor), and w is the width of the conductor (resistor).

For example, for a heating module with a heating conductor length Lc_heat of <NUM>, a width of the heating conductor wc_heat of <NUM>,<NUM>, and a heating conductor film thickness of <NUM> micrometer, the resistance R is approximately <NUM> ohm for aluminum.

By combining equations <NUM> and <NUM> above, the power is given by: <MAT> i.e. the power increases with the square of the voltage, U, and is decreased with the inverse of the resistance R.

Because the resistivity is a material parameter, and the conducting heat film thickness is a physical parameter to be chosen, the power may be written as: <MAT>.

This means that for a chosen type of heat film, the wanted power P is most easily controlled by the voltage, and then by the length Lc_heat and width wc_heat of the heating conductor (resistor).

Since all electrical power P is converted to Joule heat Q, Pheat = dQ/dt, Pheat is equal to P. The time derivative of Joule heat Q, dQ/dt, which corresponds to a flow of thermal energy. The heat flow, dQ/dt, will flow in the negative direction of the temperature gradient.

The power supplied P will be transformed into heat flow, dQ/dt, which will flow downwards dQ/dtdown to the under lay structure by conduction dQ/dtcond, and upwards, dQ/dtup, by convection dQ/dtconv and radiation, dQ/dtrad, and for non-equilibrium to the rise of the temperature of the board/panel, dQ/dtboard.

For non-equilibrium the temperature of the board will be rised by dQ/dtboard.

Regarding the temporal behavior, the temperature derivative with regard to time of the board/panel is: <MAT> where dT/dt is hence proportional to dQ/dtboard, and obviously, the temperature will rise if dQ/dtboard is not zero.

If the board is well insulated from the underlay structure, dQ/dtcond will be small, and hence the temperature gradient in the board/panel will be small, therefore the temperature will approximately follow a first order differential equation. The time dependence of the board/panel will then be: <MAT> where Tinital is the temperature of the board/panel before the voltage V is applied, Tend is the final temperature, and tau is the characteristic time constant. <MAT> and for tau per area unit: <MAT>.

Regarding the heat flow dQ/dt and temperature rise of the board/panel, the temperature rise on the surface of the board/panel will be dependent on the power P, the ambient temperature Tamb, the thermal resistance downwards, Rth down (between the heat film and the ambient floor), the thermal resistance between the film and the ambient air Rth_up. Each layer of the board/panel has its own thermal resistance, i.e. for the board/panel substructure Rth_sub, any dampening layer under the board Rth_damp, the heating film substrate Rth_substrate, the covering layer, Rth_top, and for the interface between the covering layer and the ambient air, Rth_conv. The thermal resistances downwards add in series, and the thermal resistances upwards add also in a series. However, the total thermal resistance downwards and the total thermal resistance upwards is combined in a parallel manner to a total thermal resistance, Rth_tot: <MAT> <MAT> and <MAT> Which may be written: <MAT>.

The temperature increase ΔTfilm in the heating film conductor (resistance) is given by: <MAT>.

The thermal resistance for a solid material Rth_cond due to thermal conduction is given as: <MAT>.

The thermal resistance convection is given as: <MAT>.

Some non-limiting examples of materials and thermal resistances are given in Table <NUM> below.

In the non-limiting example above, an equal heat flow, dQ/dt, in both directions, upwards and downwards, is provided, assuming that the underlay structure has the same temperature as the ambient floor.

The heat flow due to radiation dQ/dtheat is given by: <MAT> where epsilon is the emissivity factor and SB the Stefan-Boltzmann's constant.

For a surface in a cavity, the radiation has to consider the view factor F, so the heat flow due to radiation becomes: <MAT> where F ranges, i.e. is in the interval, from <NUM> to <NUM>.

The surface temperature of the panel is thus dependent on heat leakage to the underlay structure. For a well insulated floor panel, e.g. for <NUM> expanded polystyrene (PS), the temperature rise will be approximately <NUM> degrees for a power supply of 50W/m<NUM>, and <NUM> degrees for 25W/m<NUM>. If the insulation is poor, however, such as e.g. <NUM> PS, the temperature increase will be less, for example <NUM> degrees at <NUM> W/m<NUM>, according to experiments.

The electrical power P has to be supplied to the heating area, i.e. to the heat providing layer. Assuming two parallel power rails, i.e. the first and second parallel longitudinal coupling elements, the current to the heating area can be tapped at different places.

A longitudinal coupling element (a power supply rail) has a resistance according to: <MAT> which e.g. for an aluminum rail with a width, wrail, of <NUM>, and a height of <NUM> micrometer, and a length of <NUM> will have a resistance of <NUM>,<NUM> ohm.

For a panel which is connected to the power supply at one end, i.e. both polarities P1 and P2 are connected to one end side of the panel, the effective resistance will be <NUM> * Rrail, except for the modules/sections in the far ends. However, if the power supply connections are placed on opposite sides of the panel, the effective resistance will be Rrail.

Between adjacent panels coupled together, there are electrical connections having contact resistances Rcontact. As a non-limiting example, a typical contact resistance may be <NUM> ohm.

Rail resistances and contact resistances will add in series giving a power resistance: <MAT>.

It will be a voltage drop along a board due to the rail resistance Rrail, and it will be a voltage drop between boards/panels along the floor due to contact resistance Rcontact.

The voltage drops are proportional to the current I. Using multiple boards/panels in a row means that the voltage drop will increase as the square of the length of the row, because the current will increase proportional with the length, and the power resistance Rpower will increase proportionally with the length of the floor/row too. Hence, the heat flow dQ/dtheat will decrease with the power of <NUM>. Hence the power resistances are of importance for large floors.

The power resistance Rpower is twice the size if the power supply is connected on one side of the floor/panel/row, compared if the power supply is connected on the opposite sides of the floor/panel/row. This is thus an advantage for the above described embodiment in which the first P1 and second P2 polarities are supplied to opposite ends of the panel.

As a non-limiting one panel/board example, for a <NUM> micrometer and <NUM> wide aluminum heating film, <NUM> long acting as a heat conductor (resistance), the resistance is approximately <NUM> ohm. If the electrical supply is performed by the same film, but with <NUM> wide power rails/coupling elements, the power rails/coupling elements will have a resistance of approximately <NUM> ohm. With a contact resistance of <NUM> ohm, the power rail/coupling elements resistance is dominating. For a board/panel with three heating modules/sections, the heating resistances are in parallel, and the power resistances are in series. The board/panel will then have a heating resistance of <NUM> ohm, and a total power resistance of <NUM> ohm for same end side power supply connection. Correspondingly, the panel/board will have a <NUM> ohm total power resistance for an opposite end side connection, leading to a power drop of approximately <NUM>% for both cases. This indicates the power supply is adequate within a board/panel, with only the film.

Claim 1:
A panel (<NUM>) comprising:
- a base layer (<NUM>);
- a heat providing layer (<NUM>) attached to said base layer (<NUM>), said heat being created by electric energy;
- a covering layer (<NUM>) attached to said heat providing layer (<NUM>);
- first (<NUM>) and second (<NUM>) opposite longitudinal sides including first (<NUM>) and second (<NUM>) longitudinal panel coupling means, respectively, arranged for coupling said panel (<NUM>) to adjacent panels (<NUM>, <NUM>,..., <NUM>);
- first (<NUM>) and second (<NUM>) opposite end sides including first (<NUM>) and second (<NUM>) end panel coupling means, respectively, arranged for coupling said panel (<NUM>) to adjacent panels (<NUM>,<NUM>,..., <NUM>); whereby
- at least first (<NUM>) and second (<NUM>) longitudinal grooves arranged in said base layer (<NUM>) from said first end side (<NUM>) to said second end side (<NUM>) and facing said heat providing layer (<NUM>), said at least first (<NUM>) and second (<NUM>) longitudinal grooves being arranged in parallel with, and having at least first (<NUM>) and second (<NUM>) distances to said first (<NUM>) and second (<NUM>) longitudinal sides, respectively; and
- at least one electrical end connector (<NUM>) arranged at one or more of said first (<NUM>) and second (<NUM>) end panel coupling means, said at least one electrical end connector (<NUM>) including first (<NUM>) and second (<NUM>) end portions, said first (<NUM>) and second (<NUM>) end portions being at least partly electrically conductive and at least partly protruding from said one or more of said first (<NUM>) and second (<NUM>) end panel coupling means, thereby providing an electrical connection between said heat providing layer (<NUM>) of said panel (<NUM>) and a corresponding heat providing layer of at least one adjacent panel (<NUM>, <NUM>) coupled to said panel (<NUM>).