DE19622788A1 - Electrical resistance heating for room air conditioning - Google Patents

Abstract

The heating system uses an electrically conducting heating film (11) heated by electrical current and consisting of a mixture of graphite particles bound by a setting material. Current carrying metal electrode strips (6) are mounted on both sides of the film. The mixture is formed of graphite particles and bonding material diluted with water and is applied, e.g. by spreading or spraying, to a carrier plate which absorbs moisture so that the surface load relative to the electrical heating power is 20 to 60 W/m2. The carrier plate is made of a conventional plaster board plate (2) for interior use with a heat insulating film (4) on its reverse side.

Description

The invention relates to an electric underfloor heating, using one by electricity heatable electrically conductive heating layer according to P 195 38 686, consisting of a Mixture of graphite particles and water-dilutable water glass as a binder is applied by brushing, spraying, screen printing or the like, with two parallel opposite sides of the heating layer metallic strip-shaped Electricity supply electrodes are provided for air conditioning in apartments and Buildings that are both in drywall construction and in a bound substructure multilayer, at least from thermal insulation, a load distribution layer and one Floor covering layer have existing floor construction.

Known electric floor heating systems generally have a Power supply device heatable wire or strip-shaped Heating conductor or thin and flexible heating foils with an electrically insulating plastic on, which is conductive by embedded graphite particles.

In DE patent 16 15 257, the electrically heatable heating conductor consists of a conductive film having narrow elongated openings forming a meander pattern are limited by arms and by various bridges. For the production is in advantageously used a thin and flexible aluminum foil, which is very cheap and should be used as floor, wall and ceiling heating. The aluminum foil is slotted in the longitudinal direction by narrow parallel arms and with end clamps as well Cross connections for connecting the heating film and for supplying an operating voltage of less than 50 volts.

Also known after Elektro Praxis, Fröse, Electrical Heating Systems, Pflaum Verlag Munich, 1995, page 61/62, heating foils made of flat plastic, the narrow ones Strips of graphite particles are mixed. These are in the range of Underfloor heating is usually used with an area output of 100 W / m² and with operated at a voltage of 220 volts. Because of this thing is mechanical protection the heating foil is necessary in any case, because of a missing protective conductor  Use only with protective insulation is possible. In the area of building construction, there should be a screed layer provide suitable mechanical protection.

Such strip-shaped heating lines and heating foils similarly require as with floors heated with piping and hot water, on certain Areas to prevent hot spots on the floor. With yourself crossing electrical conductor tracks must therefore at each crossing point conductive cross section of the aluminum foil can be increased. Otherwise is in such places, at which is to be feared due to the build-up of furniture or the like, one A recess in the heating system is provided to allow local overheating of the floor can be avoided.

In the case of floor constructions heated with pipelines, it is known from practice that at a built-in heating screed a surface temperature of 33 degrees plus not may be exceeded. A heat build-up from furniture and the like can, however, result in a lead to significantly higher surface temperatures. Along with this, the Peel off the step covering and be affected by the formation of cracks. For this Basically, low surface temperatures are absolutely necessary in order to be heated Floor constructions with tile, natural stone or cast stone coverings without damage remain (IRB Literature Selection No. 1540, "Damage to heated floors", 3rd edition 1992, Page 22 ff.). If the laying mortar is used when laying ceramic tiles in the mortar bed is not non-positively connected to the substrate, this can result from the mortar bed and the existing composite system can deform and warp as soon as thermal Length changes in the material layers occur by the calculated elongation of the Screed is twice the tiling.

There is also a strong differentiation in terms of thermal conductivity. Out This different tendency to change results in different shear stresses and Tensions within the floor construction. It is evident from this that using a heating foil made of plastic practically in a conventional manner underfloor heating is not feasible. If the heating foil is placed on the surface of the screed, it can there is no bond between the mortar bed and the screed. On the other hand, an in poured the screed heating foil as a separating layer, which the screed structure in two flat bowl-shaped screed layers dissected with less bending stiffness. Thereby  a double-thick screed covering may be required if the prescribed Dimensions in the screed structure should be observed. As a result, the Available clear height of a room unfavorably used.

As stated in DR patent specification 656 196, an electric ball is also used in this ball Underfloor heating due to the large-scale heat storage in the heating screed uneconomical because the heating output is difficult to regulate and does not change Weather conditions is adaptable.

In the event of sudden sun exposure, the screed stored in a strongly heated screed Heat and the sun's heat coming in from outside easily overheat the room to lead. By dissipating the heat and by ventilating the windows there is a loss of energy. On the other hand, the heated screed takes a long time to heat up before heat is given off can be. The heat stored in the heating screed is lost when the heating of the room should be interrupted.

As a result, the invention aims at avoiding the disadvantages described State of the art an electrical underfloor heating for air conditioning in apartments and buildings using an electrically heatable and controllable electric conductive heating layer, when used in the floor construction both in Drywall construction as well as with the bound substructure due to thermal length change none Damage in the floor covering is detectable.

According to the invention, the object is an electric floor heating according to P 195 38 686 solved in that the electrical heating layer at the top with drywall at least with the Load distribution layer and, in the case of a bound substructure, both with the load distribution layer, if necessary with the application of a leveling layer, as well as with the floor covering layer by means of a thin bed layer or by means of an adhesive layer or a wear layer is non-positively connected. As a result, in the heating layer and, for example, in a Mortar bed laid ceramic flooring layer no cracks or bulges occur.  

According to a further embodiment of the invention it is provided that the compensation layer and the adhesive layer is water-soluble in the initial state and in the hardened state is water-insoluble and frost-proof. When using a water soluble The compensating layer can be diluted and used as a self-leveling material will.

In addition, it is provided in the context of the invention that for the manufacture of the Electric heating layer used binder with the binder for the leveling layer and the binder for the adhesive layer is identical.

According to a preferred embodiment of the invention, the binder for Compensating layer and the adhesive layer made of water glass, which can be diluted with water and in self-leveling of any consistency or together with fillers as a pasty adhesive can be used, for example, for laying ceramic tiles. Water glass, Soda water glass in particular is generally considered to be an excellent inorganic binder known that is the same with regard to its thermal and heat-conducting properties behaves like a floor covering made of ceramic materials. As a result, can especially between the floor covering layer and the heating layer, no harmful shear or tensile stresses occur. When using a screed layer or one with mineral binder produced load distribution layer takes place when using water glass a chemical reaction between parts of the binder and the screed material or the load distribution layer instead. The chemical bond to the Bonding based on interfaces leads to high adhesive forces and includes in The result is an extremely durable material connection between the Floor covering layer and the load distribution layer, which in the following with a Embodiment and will be explained in more detail with reference to drawings.

In the drawings belonging to the embodiment shows

Fig. 1 is a floor heating with a bound base and

Fig. 2 is a dry construction floor construction with underfloor heating in a schematic representation.

The floor construction consists of several layers, all of which must ensure adequate heat and sound insulation and wear resistance of the floor. The following exemplary embodiment shows in highly schematic form in FIG. 1 a floor construction with a floating screed, which is comparatively suitable for an apartment partition ceiling. On the unfinished ceiling 1 there is a thermal insulation layer 2 for soundproofing and thermal insulation in order to prevent the heat transfer into the building structure. Light powdered or granular fillings, mats, plates and shaped pieces of porous or fibrous organic or inorganic materials with a particularly low thermal conductivity can be considered as thermal insulation materials. Conventional insulation panels made of polystyrene extruded foam or polyurethane foam panels are particularly suitable for this purpose, as they have high compressive strength in addition to high insulation performance. In addition, alternative insulation materials such as cork, cellulose or mineral granules coated with bitumen are particularly suitable, especially expanded clay.

The thermal insulation layer 2 must not be moistened because it then loses its insulating effect. For this reason, it must be protected against moisture by an overlying barrier film 3 , which is particularly important in wet rooms and in the case of a bound substructure. The overlying load distribution layer 4 , namely with screed 4 ', thus "floats" on the thermal insulation layer 2 without touching the raw ceiling 1 or a wall, not shown. In the floating installation a correspondingly thick screed 4 ', for example anhydrite, magnesia or cement screed, with a large surface pressure is necessary to compress the thermal insulation layer 2 as far as possible by applying screed 4 '. Floor screed 4 'requires a minimum nominal thickness, which must not be less than 35 mm. When laying tiles on floating screed 4 ', a layer thickness of 45 mm is required.

If any unevenness in the load distribution layer 4 is to be compensated, a thin, self-leveling compensation layer 5 is applied to the top of the screed 4 ', which enables a completely smooth and even surface. Commercially available leveling compounds are suitable for this purpose, the handling of which is known and has not been explained further. With regard to the invention, however, a balancing compound comprising water glass is also particularly suitable, which enables a cohesive structure of the entire floor construction.

At the level of two opposite end faces of the load distribution layer 4 , a current supply electrode 7 is provided parallel to the floor edge 6 on both sides of the compensation layer 5 , which is glued directly onto the compensation layer 5 or, if appropriate, onto the load distribution layer 4 with a water glass adhesive. The power supply electrode 7 , which is composed of a thin film strip of an electrically highly conductive material, preferably of copper, is connected to a power supply device, not shown, which can be operated mainly with protective extra-low voltage.

An electrically conductive heating layer 8 , which is composed of a mixture of graphite particles and a water-dilutable binder, is applied to the surface of the floor enclosed by the current supply electrodes 7 by brushing, spraying, filling or, if appropriate, by screen printing. Suitable as a binder for this purpose is water glass, in particular sodium water glass, which can be made available comparatively inexpensively.

The ratio of the volume fractions based on the initial constituents of the graphite particles to the water glass should be in the range from 1: 1 to 1: 2. As a result, the desired heating power can be produced by applying the heating layer 8 once. The heating output should preferably be 20 to 60 watts / m² so that the temperature of the floor to be heated cannot exceed 33 degrees plus. As a result, there is no risk of damage to the floor construction. It is also advantageous that the heating layer 8 is arranged on the top of the load distribution layer 4 . The screed 4 'means an additional heat insulation layer 2nd The heat generated in the heating layer 8 acts directly on the floor covering layer 9 to be heated. As a result, the heating output can respond fairly quickly and can be dimensioned very small.

After completion of the heating layer 8, a ceramic layer can be laid floor covering 9 of slabs or tiles in a mortar bed 10 directly to the heating layer. 8 When using a mortar bed 10 there is excellent adhesion between the floor covering layer 9 and the heating layer 8 . The adhesion can be increased further if the tiles are glued instead of a mortar bed 10 with an adhesive layer 10 ', the adhesive having water glass as a binder. In this case, a chemical chaining of the floor covering layer 9 with the heating layer 8 is caused by chemical reaction, which is itself connected to the load distribution layer 4 or the screed 4 '. Thus, the floor covering layer 9 is also connected to the load distribution layer 4 by means of the heating layer 8 frictionally with each other. Because of this, cracks in the floor covering layer 9 are completely excluded. All ceramic floor coverings, tiles or tiles made of glass, marble, natural or artificial stone can therefore be used as the floor covering layer 9 without restriction. Otherwise, if a textile floor covering, carpet, wood, or parquet floor is appropriately, a heating layer 8 against wear preserving and sealing wear layer 11 is provided instead of a mortar bed 10, which is finally coatable on the heating layer. 8 Cement screed, plastic screed, asphalt screed, self-leveling screed or the like is suitable for this purpose, which can enable long-term assembly with the heating layer 8 . On this occasion, the efficiency of the underfloor heating can be further improved by means of heat-conducting additives. In addition, the efficiency of the underfloor heating can be improved if the strengthening additives, for example in the form of fibrous materials, are contained in the wear layer 11 . As a result, the thickness of the wear layer 11 can be made smaller and the heat transfer can be optimized in relation to the strength of the wear layer 11 .

The same advantages can also be realized with a floor heating system implemented in drywall construction, which is to be explained below with the drawing shown in FIG. 2. In dry construction, an insulating layer 12 is applied to a raw ceiling 1 , which is formed by a loose bed of mineral inflatable bodies or the like coated with bitumen. The fill can easily adapt to existing cavities if, in contrast to the drawing chosen for reasons of simplification, a wooden ceiling with a layer of beams is present. The fill is leveled evenly in one level by subtracting. A load distribution layer 4 made of covering plates is then placed on the insulating layer 12 and is stiffened on the longitudinal sides by springs 14 inserted into grooves 13 of adjacent plates.

A leveling compensation layer 5 can subsequently be applied to the load distribution layer 4 in order to ensure a smooth surface for the electrical heating layer 8 . If a water-thinnable leveling layer 5 is to be used, a barrier film 3 is again recommended according to FIG. 1 between the insulating layer 12 and the load distribution layer 4 , in order not to endanger the function of the insulating layer 12 by penetrating water. The electrically conductive heating layer 8 is applied to the top side of the load distribution layer 4 prepared in this way, which is thereby non-positively connected to the load distribution layer 4 with the binder contained in the heating layer 8 . The load distribution layer uppermost 4 arranged heating layer 8 allows direct heat radiation to the overlying floor construction and a low self-heating of the place of a screed layer built-in load distribution layer 4, which is thereby exposed to a slight extent the deleterious thermal expansion. The durability of the heating layer 8 is therefore of unlimited duration.

A particularly simple and cost-effective representation of the floor construction is achieved if the load distribution layer 4 consists of plates which are coated with the electrically conductive heating layer 8 ready for installation. The production of these plates is described in detail in DE Offenlegungsschrift 196 00 228, to which reference is hereby made. Particularly suitable here are mineral-bonded load distribution plates reinforced with fibrous materials or composite building boards with groove 13 and tongue 14 , which, as is known, have thin current supply electrodes 7 which can be inserted into groove 13 on the end faces. As a result, a heating layer 8 extending over the entire floor can be realized by simply lining up load distribution plates. To protect the heating layer 8 , a wear layer 11 is expedient against mechanical wear, on which a pressure distribution layer 15 can finally be placed. This can be formed from large-format load-bearing plates or floor elements made of wood-based materials, which likewise have a tongue and groove profile 13 , 14 in the side area in order to ensure a high level of stability during installation. As a result, the pressure distribution layer 15 forms an excellent laying ground for parquet, carpeting and other soft coverings. Accordingly, plastic soft coverings in particular can be used without any problems, since a low heat output of the heating layer 8 is required for good heat transfer. Overall, this has a favorable effect on the economy and the service life of the underfloor heating.

Claims (9)

1. Electric floor heating according to P 195 38 686, using an electrically conductive heating layer which can be heated by current, consisting of a mixture based on graphite particles and water-dilutable water glass as a binder, which is applied by brushing, spraying, screen printing or the like, wherein Metallic strip-shaped power supply electrodes are provided on two parallel opposite sides of the heating layer, for room air conditioning in apartments and buildings, which have a multi-layered floor construction consisting of at least thermal insulation, a load distribution layer and a floor covering layer, both in drywall construction and in a bound substructure, characterized in that that the electrical heating layer ( 8 ) at the top in drywall construction at least with the load distribution layer ( 4 ) and in a bound substructure with both the load distribution layer ( 4 ), optionally with application of a compensation sschicht ( 5 ), and with the floor covering layer ( 9 ) by means of a mortar bed ( 10 ) or adhesive layer ( 10 ') or with a wear layer ( 11 ) is non-positively connected. 2. Electric floor heating according to claim 1, characterized in that the compensating layer ( 5 ) and the adhesive layer ( 10 ') is water-soluble in the initial state and water-insoluble and frost-proof in the cured state. 3. Electric floor heating according to claim 1 and claim 2, that the compensating layer ( 5 ) is self-leveling. 4. Electric floor heating according to one or more of claims 1 to 3, characterized in that the binder used for the production of the electrical heating layer ( 8 ) with the binder for the compensating layer ( 5 ) and the adhesive layer ( 10 ') is identical . 5. Electric floor heating according to one or more of claims 1 to 4, characterized in that water glass is provided as a binder for the compensating layer ( 5 ) and the adhesive layer ( 10 '). 6. Electric floor heating according to one or more of claims 1 to 5, characterized in that for laying a ceramic floor covering layer ( 9 ), in particular tiles, water glass or water glass is provided as a binder for the mortar bed ( 10 ). 7. Electric underfloor heating according to one or more of claims 1 to 6, characterized in that instead of a mortar bed ( 10 ) a heating layer ( 8 ) against wear and sealing and sealing wear layer ( 11 ), for example cement screed, plastic screed, asphalt screed, liquid screed or the like is provided, which can finally be applied to the heating layer ( 8 ). 8. Electrical underfloor heating according to one or more of claims 1 to 7, characterized in that the efficiency of the underfloor heating is increased by heat-conducting additives in the wear layer ( 11 ). 9. Electrical underfloor heating according to one or more of claims 1 to 8, characterized in that the efficiency of the underfloor heating is increased by additives in the wear layer ( 11 ) which increase the strength, for example in the form of fibrous materials.