SK282911B6 - Heating element for surface heating - Google Patents

Abstract

Heating element (1) for surface heating, having a cavity (3) for transporting the heat transfer medium and a jacket (2), made from plastic and/or metal, enclosing the cavity, characterised in that the jacket is constructed in such a way that its outer surface assumes different temperatures even when the heat transfer medium passes through in a uniform fashion. The heating element can in principle also be used to cool surfaces, if a cooling medium is used instead of the heat.

Description

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchange element for large-area heating or cooling comprising a cavity for transporting a heat transfer medium surrounded by a plastic or metal sheath and further to large-area heating or cooling, in particular for floor heating or cooling.

BACKGROUND OF THE INVENTION

From AT-378 846, heating pipes of metal or plastic with a circular, oval or elliptical cavity cross-section are known. The issue of large-scale heating, especially underfloor heating, is related to the surface temperature, which is perceived as uncomfortable in many places and which is not equally comfortable for everyone. Due to the known heating pipes incorporated in the solidifying or hardening material, relatively large temperature differences occur on the heating surface, the so-called heating pipes. temperature pulsation. This is often felt uncomfortable. In addition, it does not meet the basic requirements for large-area heating, in particular underfloor heating. Large-area heating should have a low and constant temperature over the entire surface of the heated area for health reasons, low starting temperature and low down temperature for economic reasons.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a heating or cooling element with a cavity for transporting a heat transfer medium and a plastic or metal sheath arranged around the cavity to allow large-area heating or cooling construction, especially underfloor, having substantially lower thermal pulsations. However, this object is solved by a heat exchange element in a large-area heating system comprising a cavity for transporting a heat transfer medium surrounded by a plastic or metal jacket equipped with regions of different thickness and different thermal conductivity according to the invention. greater thickness in those parts that are facing and / or facing away from the heating surface after installation of this element than in the other parts, and / or the housing in those parts that are facing and / or facing away from the heating surface is provided with an insulating slot filled with material that is a bad heat conductor. The material may be, for example, air.

Similarly, a heat exchange element for large-area cooling is formed, comprising a cavity for transporting a cooling medium surrounded by a plastic or metal sheath provided with regions of higher and lower thermal conductivity, according to the invention, which is based on the sheath having a greater thickness. those parts that are facing and / or away from the cooled surface after installation of this element as in the other parts, and / or the housing in those parts that are facing and / or away from the cooled surface is provided with a material that is a poor heat conductor . The material may be, for example, air.

According to a preferred embodiment, the jacket of the heating or cooling element has an oval or elliptical shape, the cavity housed in the jacket having a circular cross-section. This achieves that the sheath has areas of varying thickness. It has been shown that the heat transfer can be easily controlled such that the heating or cooling element according to the invention has a stronger, i.e., a higher heat output. j. thicker areas that, when assembled, face the heated or cooled surfaces than the areas facing each other.

BRIEF DESCRIPTION OF THE DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail with reference to the drawing, wherein FIG. 2, the four tubes are schematically shown in section, FIG. 1 and FIG. 2 represents the prior art, FIG. 3 shows a heating or cooling element according to the invention, in another embodiment, FIG. 5 shows a heating or cooling element according to the invention, in another embodiment, FIG. 6 shows a heating or cooling element according to the invention in a further embodiment, and FIG. 7a, 7b show a heating or cooling element according to the invention, in yet another embodiment.

DETAILED DESCRIPTION OF THE INVENTION

In the diagram of FIG. 1 shows typical temperatures and temperature pulsations of four tubes, according to the prior art, with a span of 150 mm and an initial temperature of 40 ° C, schematically shown in cross-section in FIG. 2, where each abbreviation means:

OTS vertical oval tube with dimensions of 17/24 mm KTV round tube with a larger radius of 20.94 mm OTL vertical oval tube with dimensions of 24/17 mm KTM round tube with a smaller radius of 17 mm.

Depending on the variation of the pipe span in connection with the change in the initial temperature, the temperature pulsation may still substantially increase. For health reasons, the surface temperature of the floor in underfloor heating should be lower than the surface temperature of the feet of the human body (which cannot be the same as body temperature) so that heat can be transferred to the floor. The explanation of the temperature pulsation of FIG. 1 is apparent from FIG. 2, wherein the four heating tubes are positioned above the thermal insulation shown by the helical lines, in the floor material, bounded by horizontal lines. Each known heating pipe, irrespective of the cross-section, transfers heat evenly over its entire surface, where heat radiation is shown by arrows, so that on the floor and thermal insulation the highest surface temperature occurs immediately above and below the top of the pipes. surface temperature.

In FIG. 3 shows a heating surface according to the invention, the cavity 3 having a circular cross-section formed by a plastic tube and the oval-shaped casing 2 having reinforced walls 2a, 2b in its upper and lower parts. The tubes can be provided at their ends for the distributor connection with an annular shoulder 1, according to FIGS. 4a, 4b, whereby known welded, pressed or screw connections can be made easily and reliably. The annular shoulder 1 is shown in front view in FIG. 4a and in a side view in the direction of the arrow A in FIG. 4b. In the side view, the reinforced walls 2a, 2b of the top and bottom of the housing 2 are further shown in a cavity 3. It has been shown that with the heating elements of the heating element thus formed, thermal pulsations can be practically avoided when the tubes are embedded in the floor in spiral lines or .

In FIG. 5 shows a heating element with a cavity 3 formed by a heating tube of plastic or metal with a circular cross-section, the oval-shaped housing 2 being provided with reinforced walls 2a, 2b in its upper and lower parts. In the reinforced walls 2a, 2b an insulating slot 6 is provided which provides heat transfer according to the requirements of the invention. The insulating slot 6 is filled with a material which is a poor heat conductor, which material is most often air, and other insulating materials known in the construction or heating and cooling techniques may also be used. The ends of the tubes can be provided with a circular shoulder 1 according to FIG. 4a, 4b, whereby known weld, press or screw connections can be made easily and reliably.

In FIG. 6 shows a heating element with a heating tube of metal with a circular cross section, with plastic insulating reinforced walls 2a, 2b in the upper and lower part of the housing 2, which may (shown in the lower half) or not (upper half) be provided with an insulating slot 6; which again provides heat transfer according to the requirements of the invention. The pipe ends can be provided with a circular shoulder 1 according to FIG. 4a, 4b, whereby known weld, press or screw connections can be made easily and reliably.

The heating elements according to the invention can be inserted into all known fastening means, such as pipe couplings, retaining strips, plates and the like, according to the applicable standards or standards. according to the state of the art, both hot and cold.

However, by reinforcing this region of the heating element according to the invention which faces away from the heating surface, the heat loss in the floor can be reduced and the connecting parts such as supply and return pipes can be permanently attached to the heating elements, for example by welding. This arrangement is shown in FIG. 7a, 7b, in the longitudinal direction of FIG. 7a and crosswise in FIG. 7b shows a heating element with a plastic tube with a circular cavity 3 and with reinforced walls 2a, 2b of the housing 2 in its upper and lower parts. The reinforced walls 2a, 2b can be inserted perpendicularly or obliquely in the non-detachable connection points 4. This makes it possible to produce by means of extrusion of the collecting tube with a high long-term fatigue limit and very advantageous production costs. from the collecting pipe to the inlet or return pipe is carried out by a circular shoulder 1, which at the same time creates a safe stop for non-detachable connection methods.

Welding or otherwise permanently connecting the manifolds to the inlet or return pipe is of great importance because the division of the hot water stream from the inlet pipe into several manifolds provides significant advantages in terms of pressure loss and flow velocity. Low loss and low flow rate result in the use of small energy-saving pumps and noiseless operation.

Known joining methods, such as butt joints or inserting distribution heating pipes into pipes with relatively thin walls, pose the risk that the joints may leak at high continuous loads. Plastic injection molded parts have a lower long-term fatigue limit and lower life than extruded plastic tubes with the same wall thickness. The depth of the joints produced by welding or other permanent joints should be about the size of the diameter of the heating manifold fitted to ensure the greatest possible long-term safety. For example, if a 8 mm diameter heating pipe is inserted into the collecting pipe, then the depth of the joint should be about 8 mm.

The heating element according to the invention can also be used as a cooling element for large-area cooling, while achieving uniform cooling of the surfaces, while avoiding temperature pulsation. The invention therefore also relates to a cooling element having the same constructional features as the heating element according to the invention.

The invention also relates to a heating or cooling element for large-area heating or cooling, which can, for example, be air-conditioned.

The invention will now be described in more detail by way of the following example. The heating element with the cross-section shown in FIG. 3, was produced by a known method by extrusion from polypropylene having the following dimensions:

wall thickness 0 ⁰ 2.0 mm wall thickness 30 ⁰ 2.5 mm wall thickness 60 ⁰ 3.5 mm wall thickness 90 ⁰ 4.0 mm tube inner diameter 20 mm.

The heating element was pumped hot water (initial temperature 40 ° C, flow rate 3 L / min), and the temperatures inside the tube and on the outer surface of the jacket were measured.

Inner pipe temperature Outer temperature in plane 0 ⁰ Outer temperature in plane 30 ⁰ Outer temperature in plane 60 ⁰ Outer temperature in plane 90 ⁰ ° C

38.23 ° C

38.92 ° C

37.35 ° C

37.07 ° C.

By providing a different wall thickness, the surface temperature of the heating element can be varied, and consequently, for example under floor heating, the heat dissipation at the top of the floor can be varied so as to equalize the thermal pulsation. The variation in the surface temperature of the heating element according to the invention is the greater the greater the differences in the wall thickness and the wall thickness. the insulating slots 6 formed in the pipe of FIG. 6th

Claims (4)

PATENT CLAIMS A heat exchange element for large-area heating, comprising a cavity (3) for transporting a heat transfer medium and surrounded by a plastic or metal casing (2) equipped with regions of different thickness and conductivity, characterized in that the casing (2) ) has a greater thickness in those parts that are facing and / or facing away from the heating surface after installation of the element, and / or the sheath (2) is in those parts that are facing and / or facing away from the heating surface, provided with an insulating slot (6) filled with material that is a poor heat conductor. Element according to claim 1, characterized in that its shell (2) has an oval or elliptical opening, the cross-section of its cavity (3) being circular. A heat exchange element for large-surface cooling, comprising a cavity (3) for transporting a cooling medium surrounded by a plastic or metal casing (2) equipped with regions of different thickness and conductivity, characterized in that the casing (2) ) has a greater thickness in those parts that are facing and / or facing away from the cooled surface after installation of the element, and / or the sheath (2) is in those parts that are facing and / or facing away from the cooled surface, provided with an insulating slot (6) filled with material that is a poor heat conductor. Element according to claim 3, characterized in that its shell (2) has an oval or elliptical opening, the cross section of its cavity (3) being circular.