WO2005036930A1

WO2005036930A1 - Heating of surface areas

Info

Publication number: WO2005036930A1
Application number: PCT/GB2004/004243
Authority: WO
Inventors: David Gerald Catley; Pritpal MANGAT
Original assignee: Inditherm Plc
Priority date: 2003-10-08
Filing date: 2004-10-07
Publication date: 2005-04-21
Also published as: GB0323539D0

Abstract

The invention relates to heating means for surface areas, such as walls, floors, and ceilings of rooms or other areas of buildings or surface areas of roadways, drives and deckings. Surface areas of e.g. concrete or composite panels, tiles and the like are known to be heated by hot water pipes or electric cable heating means that are expensive to install and to run. in certain circumstances, such as in rooms or areas of buildings there is a need to prevent access to mains electricity and yet have a means of maintaining the temperature of the room or area at a prescribed level. The object of the invention is to meet these and other objectives, and is met by a heating means comprising a sheet of flexible semi-conductive material positioned inwardly of or below the surface of the area to be heated, and connected to a source of electrical supply.

Description

HEATING OF SURFACE AREAS This invention relates to heating means for surface areas e.g., of concrete or other building, construction or surfacing materials. In the construction industry there is the increasing use of modular, preformed units to serve as the external or internal walls of a building or the floors of buildings. Thus, concrete panels are increasingly used to construct walls and floors. Composite panels of such as fibreboard and the like are used for internal non-load-bearing walls, plaster panels are known to line walls and ceilings, and concrete panels and tiles of suitable materials are used for floor surfaces. Elsewhere there is the continued use of such as concrete and of asphalt to form road surfaces and the surface of play areas. In sport and with outdoor activities, adverse cold weather conditions can lead to hard or frozen surfaces making the playing of games dangerous and at times impossible. With buildings, consideration has already been given to the incorporation of water pipes to carry hot water, in an attempt to provide radiant heat from a concrete panel and hence a wall surface, to serve as a room heater. Underfloor water pipe systems are also known to heat up the floor of a building/room. Whilst able to function to heat walls and floors of rooms, pipe lines or cables provide a localised source of heat, and whilst there may be a dispersal of heat as it reaches the surface to be heated, it is inevitably so that heating of the surface is not uniform with the presence of hotter and colder regions without the use of excessive amounts of pipe lines or cables, and the provision of heat such as by way of a hot water or steam systems or by electrical cables serving as resistance heaters, has costs that are relatively high. The object of the present invention is to provide an improved means of heating a surface area of a room or other area of a building According to the present invention, a heating means for a surface area of a room or other area of a building comprises a sheet of flexible semi-conductive material positioned inwardly or below the surface of the area to be heated and connected to a source of electrical supply. Preferably, the sheet of semi-conductive material comprises finely divided carbon particles uniformly dispersed in an elastomeric polymer. Such a material is discussed in EP 1127356A. The density of the carbon particles in the semi-conductive material is such that with electrical power supplied, and transformed to considerably less than mains supply, there is a substantially totally uniform heating effect over the whole of the sheet of flexible semi-conductive material, and the heating effect provided by the sheet is totally controlled by the level at which power is supplied. The said sheet preferably has conductive rails along opposite edges to serve as live and return connections of electrical power. The said sheet may be embedded below one surface of e.g. a concrete panel during its construction, at a distance below that surface such that with electrical power supplied to the sheet, heat reaches the surface of the concrete panel, to provide a totally uniform source of heat over the full surface of the panel. Desirably, the semi-conductive sheet is part of an insert formed by two outer protection and preferably waterproof layers, an insulating layer and the semi-conductive sheet, the insert being oriented such that the insulating layer is facing the body of the panel and the semi- conductive sheet facing the surface of the panel to be heated. A number of such concrete panels can be erected to form a complete wall, and adjacent semi-conductive sheets suitably connected together in parallel or series or separately connected to mains, or the panel can be of a size to form the entire wall. Equally, a number of concrete panels with inserts can be laid on a prepared surface to form a floor, or a panel of a size to form an entire floor can be formed. Equally, a sandwich structure similar to the insert mentioned above can be laid on a prepared surface and concrete poured on to it and levelled to form a floor. It follows that the concept as discussed above can be applied to other building and construction materials, such as, for example, plasterboard lining panels, composite non-load- bearing walls, or to wall and floor tiles of such as stone or ceramic materials, where the flexible semi-conductive sheet can be incorporated in or attached to one surface of the panels walls or tiles. In all such instances as are briefly mentioned above, totally uniform heating of a surface area that can serve as a means of heating the walls, floor or ceiling of a building or a room or other area within a building, able to be controlled fully, and with the electrical supply not being readily accessible by a user of the building or room. In other contexts, such as road building or with driveways to domestic orpublic premises, they are frequently formed from poured concrete or bituminous materials such as asphalt. During cold winter conditions, snow and ice can be present on the surface, a source of considerable danger. Here, a sheet of flexible semi-conductive material can be laid on a prepared surface and overlaid by poured concrete or asphalt. Again, and desirably, the sheet is in sandwich form with protective waterproof outer layers and an inner insulating layer. With the sheet suitably connected to a source of electrical power, sufficient heat can be generated substantially uniformly over the road/driveway surface above the sheet, to ensure the complete elimination of snow and ice. For particularly long lengths of road or drive, the sandwich construction incorporating the semi- conductive sheet is preferably formed as panels of finite lengths, a number of panels being laid in side-by-side relationship over the width of the road and along a required length. Thus, the road surface can be heated in areas of particular dangersuch as in advance of and around bends in a road. Equally, and significantly roads can be heated to a discrete distance in advance of and beyond a bridge, particularly one with concrete stanchions. Conventional application of salt to a road surface has a marked and damaging effect on concrete structures, and the invention would allow road salting to continue for most of a roads length, and cease where a bridge is sited. It follows that the invention can also be applied to concrete bridge decking for the same purpose of avoiding de-icing by applying salt. Several embodiments of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a schematic sectional side view of a pre-cast concrete panel with an embedded heatable insert; Figure 2 is a schematic sectional plan view of a room formed from modular pre-cast concrete panels with embedded heatable inserts; Figure 3 is a schematic sectional side elevation of a room with heatable inserts in the walls, floor and ceiling. Figure 4 is an enlarged view of part of a wall of Figure 3; Figure 5 is an enlarged view of part of the floor of Figure 3; Figure 6 is an enlarged view of one form of ceiling tile of Figure 3; and Figure 7 corresponds to Figure 6 but shows an alternative form of ceiling tile. In Figure 1 a concrete element 1 , the surface 2 of which is to be heated, has a heatable insert 3 embedded therein, spaced from the surface 2. The heatable insert 3 is formed by a flexible semi-conductive sheet 4 comprising finely divided carbon particles uniformly dispersed in an elastomeric polymer, such as is discussed in EP 1127356A. The semi-conductive sheet 4 is provided to one side with a layer 5 of insulating material, the sheet 4 and layer 5 being encapsulated in an outer, waterproof, protective sheath 6. The concrete element 1 may be a pre-formed slab, able to be assembled with other slabs to form the walls or floor of a room or a bϋlding. The slabs could also serve as ceiling members. As is illustrated in Figure 2, the walls 7, floor 8 and ceiling 9 of a room of a building may be formed by modular pre-cast concrete panels with a number of heatable inserts 3 embedded in the concrete during casting. Equally, the heatable inserts could be strategically located within formers in the circumstance where the walls, floor and ceiling of a building are cast on site. As an alternative form of construction, the walls, floor and ceiling of a room can be formed in any conventional manner, and, as is illustrated in Figure 3, the walls can be lined with pre-formed dry wall or plasterboard panels 10, the rearward surfaces of which are provided with heatable sheets 11 of semi-conductive material. Also, as illustrated in Figure 3, the floor of a room can be formed by laminate or ceramic tiles 11 with embedded heatable inserts 12. Again, as illustrated, a suspended ceiling of the room may be formed by or lined with ceiling tiles 13 that may have a heatable insert 14 embedded therein or provided as a lining 15 to the rear surface of the tiles. Figure 4 shows in better detail part of the dry wall or plasterboard panel of Figure 3. Thus, the wall 7 of a room is lined with a composite formed by a dry wall or plasterboard panel 10 that has directly attached to its rearward surface a heatable sheet 11 of flexible semi-conductive material that is overlaid by a insulating layer 16 in turn covered by a protective sheet 17. Such a panel can be attached to the wall of a room in conventional manner, and the exposed surface provided with any required decorative finish. As illustrated in Figure 5, the floor 8 of a room has a solid base 18 on which is laid a heatable composite formed by a flexible sheet of semi-conductive material 19 on an insulating layer

20 behind which is a protective sheet 21 , the flexible sheet being overlaid by a protective sheet 23.

To the composite, may be applied a conventional flooring finish, such as for example ceramic tiles or laminate flooring 24. Figures 6 and 7 illustrate two forms of ceiling tiles 13. In Figure 6, the ceiling tile 13 of any conventional material has a heatable sheet 24 of flexible semi-conductive material directly attached to its rearward surface that is overlaid by an insulating layer 25 in turn covered by a protective sheet 26. In Figure 7, a heatable insert 27 is embeddedwithin the depth of the tile 13, the insert being formed by a flexible heatable sheet 28 having to one side an insulating layer 29 and to the other side a protective cover 30, the composite being encased in an outer sheath 31. As is indicated in the drawings, the flexible sheets of semi-conductive material are of a size less than the overall size of walls, floor and ceilings. Whilst each sheet may be connected separately via electrical transformers to mains supply and when different sectors of a room could be separately heated as required, the sheets may be electrically connected together and via a transformer to a mains supply for simultaneous heating as and when required. When the concrete element is a structural panel pre-formed or cast in situ, it may be provided with internal reinforcement as is indicated at 32. In the different circumstance of road construction, it will be understood that the concrete floor panel of Figure 2 with an embedded heatable insert couldequally serve as the surface of a road, and whereby during cold and inclement weather, a road surface canbe kept heated, to avoid the formation of ice. This is not only to the benefit of drivers, but has major implications in the avoidance of the need to apply copious quantities of salt containing surface treatment materials, it being widely known that salt not only damages road surfaces, but also is a cause of damage to such as concrete stanchions and supports for bridges crossing roadways. It will be further understood that the heatable insert of Figure 2 can be embedded in other road surfacing materials, such as for example asphalt, and that such heatable inserts can be embedded below the surface of such as driveways of domestic or public premises.

Claims

CLAIMS 1. A heating means for a surface area ofa room or other area of a building comprising a sheet of flexible semi-conductive material positioned inwardly or below the surface of the area to be heated and connected to a source of electrical supply.

2. A heating means as in Claim 1 , wherein the sheet of semi-conductive material comprises finely divided carbon particles uniformly dispersed in an elastomeric polymer.

3. A heating means as in Claim 1 or Claim 2, wherein the sheet of flexible semi-conductive , material has conductive rails along opposite edges to serve as live and return connections of electrical power.

4. A heating means as in any of Claims 1 to 3, wherein the sheet of flexible semi- conductive material is embedded below one surface of e.g. a concrete panel during its construction, at a distance below that surface such that with electrical power supplied to the sheet, heat reaches the surface of the concrete panel, to provide a totally uniform source of heat overthe full surface of the panel.

5. A heating means as in Claim 4, wherein the said sheet is part of an insert formed by two outer protection and preferably waterproof layers, an insulating layer and the semi-conductive sheet, the insert being oriented such that the insulating layer is facing the body of the panel and the semi- conductive sheet facing the surface of the panel to be heated.

6. A heating means as in Claim 5 or Claim 6, wherein a number of such concrete panels are erected to form a complete wall, and adjacent semi-conductive sheets suitably connected together in parallel or series or separately connected to mains, or the panel can be of a size to form the entire wall.

7. A heating means as in Claim 4, wherein a number of concrete panels with insertsare laid on a prepared surface to form a floor, or a panel of a size to form an entire floor is formed.

8. A heating means as in Claim 5, wherein the insert is laid on a prepared surface and concrete poured on to it and levelled to form a floor.

9. A heating means as in any of Claims 1 to 5, wherein the said sheet of flexible semi- conductive material or the said insert is applied to building or constructional material.

10. A heating means as in Claim 9, wherein the said sheet or the said insert is attached to or incorporated in a plasterboard panel.

11. A heating means as in Claim 9, wherein the said sheet or the said insert is applied to or incorporated in non-load-bearing walls.

12. A heating means as in Claim 9, wherein the said sheet or the said insert is applied to or incorporated in wall and floor tiles.

13. A heating means as in any of Claims 1 to 5 wherein the said sheet or the said insert is laid on a prepared road support surface and overlaid by road surfacing material.

14. A heating means as in any of Claims 1 to 5, wherein the said sheet or the said insert is applied to or incorporated in concrete bridge deckings.

15. A heating means substantially as hereinbefore described with reference to any one of Figures 1 to 7 of the accompanying drawings.