EP1645827A1 - Panel heater with indirect heating - Google Patents

Abstract

Panel radiator, which is filled with liquid, wherein the heat from the heating circuit is transmitted via a heating element indirectly to the Füllflüßigkeit in Plattenheizkörper, wherein as a heating element, a coil (17) in impressions (18) of the heating plate is installed.

The circulation movement of the filling liquid in the heating plate is divided into the "cold" and the "warm" region. So that it does not come to the mixing of the circulation flow from the "warm" and from the "cold" area, a flat radiator U- or L-profiles are provided, which extend over the entire radiator height, but only the stomata at the top and provided at the bottom of the heating plate because of the deflection of the circulation.

Description

The invention relates to a new type of non-pressurized panel radiator, which is filled with liquid and is made in a similar manner as the conventional panel radiator, but with a plate thickness of 0.4 to 0.8 mm.
The conventional panel radiators are now made in the same way throughout the world from 1.0-1.25 mm thick sheet metal and must withstand the pressure of 15 bar. The aim of the present invention is that one modifies the existing concept of conventional panel heater production insignificant while producing a new type of panel radiators made of thin sheet metal (0.4-0.8 mm) while maintaining the operating pressure of 70 bar can withstand.
The conversion of production to the new type of panel radiators does not cause any major losses in heating performance. The conversion to the new production form makes it possible to save millions of tons of sheet steel worldwide.
For the purposes of this invention, the solution is given how to incorporate a heating coil in principle in the existing configuration of a conventional hotplate with the inclusion of the laws of fluid dynamics and heat transfer and associated achieves the highest heat output in a hotplate.

Including the prior art according to the invention DE 27 30 541 A of 12.01.78 in the further (D1), the invention DE 196 53 440 A 1 of 25.06.1998 in the further (D2), the invention EP 0 807 795 A2 of 19.11.1997 in the further (D3), the invention EP 0 807 795 A3 of 10.02.1999 in the further (D4) and the invention WO 02/50479 A1 of 27.06.2002 in the following (D5), the proposed solutions of the solution according to set against this invention, while the features of the new invention are shown. The practical realization of the new idea is placed in the foreground.
In the patent D1, the principle of the radiator is incorporated with built-in heat exchanger in the way that a hermetically sealed hollow Radiator is under negative pressure and filled with the evaporation liquid. In the area of its lower edge, a conduit is installed as a heat exchanger. The heat from the heating circuit is transferred via the conduit to the filling liquid and thereby evaporates the filling liquid. This patent solution is basically different from the solution according to the new invention. The solution according to the new invention considered on the one hand, the possibility that the heat transfer medium in the hollow radiator is the filling liquid (which is depressurized) and on the other hand, the idea is given how in the heating plates of the usual production a coil can be installed while optimally Heat transfer coefficient and optimal flow dynamics can be achieved.

In the patent D2, the solution is given in such a way that a coil through the hollow radiator (preferably made of plastic) is pulled through, extending in a variant, the coil in the radiator over the entire length and over the entire height of the heating plate (evenly hook). In another variant, the heating coil is installed in the lower edge channel of the radiator, while it is provided that the hollow radiator is filled with liquid, which serves as a heat transfer medium. It is characteristic in this invention that the coil extends over the entire length of the radiator, which leads to the fact that always forms a "warm pad" at the top of the radiator, so that no circulation movement of the filling liquid in the hot plate is made. The feature of this invention (D2) is also that there is no provision for installing the coil in the conventional hot plate.
The circulation movement of the filling liquid is absolutely necessary because of the efficient heat transfer. As is known, the heat transfer coefficient depends on the coil to the filling liquid (either around the pipe or along the pipe). If, according to the invention in D2, the filling liquid in the upper layers cools down to the temperature lower than the temperature in the lower layers of the heating plate, then the falling movement of the filling liquid starts from top to bottom and mixing occurs the ascending with the falling stream of filling liquid. This leads to the cessation of the circulation movement of the filling liquid.

The patent solutions in the patents D3, D4 and D5 are similar to the patent solution in the patent D1 and apart from these patent solutions differ fundamentally from the basic idea, which is the subject of the present new patent application.
In order to bring about the practical realization of the proposed solution in the patent D2 to the prior art, it becomes necessary to register by the inclusion of physical laws, the objective solution of this new patent application and how to install a heating element in a conventional hot plate optimal flow dynamics and the ability to achieve maximum heat transfer coefficients.
In order to achieve a sufficient circulation movement of the filling liquid in the heating plate, the heating plate must be divided into the "warm" and the "cold" area. The "warm" area is understood to mean the area fraction of the heating plate in which the heating element is installed (an ascending flow forms in this area) and the "cold" area is understood to be the area proportion of the heating plate in which no heating element is placed ( in this area, a sloping flow forms). The rising and falling currents must be separated from each other, either by the existing impressions in the existing heating plate or by the specially designed internals (eg U-profiles, L-profiles or flat profiles). On the other hand, the flow resistances in the circulation movement of Füllflüssikgeit must be kept to a minimum, so that the flow rate of the filling liquid around the heating element is sufficiently large, so that the heat transfer coefficient from the heating element to the filling liquid remains large enough. The calculations show that the use of the indirect heating heaters only makes sense if the heat transfer coefficient from the heating element to the filling liquid is of the order of 600W / m ² K. It follows that the surface portions of the heating plate with rising flow and the surface portions of the heating plate with sloping flow must be in a certain ratio to each other. Likewise, the heating surface of the heating element to the outer surface of the heating plate must be in a certain ratio.

The object of the present invention is to draw attention to the mutual influences and at the same time to give a new solution to how to install a heating element in an existing radiator in order to realize its practical realization.
In order to express the advantages of the new concept compared to the usual radiators, it is close to explain the flow processes in a conventional radiator in more detail.
In conventional radiators, the heating water flows through the vertical channels from top to bottom. The farther the vertical channels are from the entry point (heating flow), the greater are the flow resistances and, correspondingly, from channel to channel, an ever smaller flow rate of the heating water flows. As a result, the temperature profiles across the length of the hot plate are different, and hence the heat transfer coefficient from the hot plate to the room air becomes smaller and smaller over the plate length [as the water value (mxCp) becomes smaller and smaller from one channel to another].
According to the present invention, because of the uniform circulation flow of the filling liquid over the height and over the length of the heating plate, the heat transfer ratios over the entire length of the heating plate are kept sufficiently constant. This has the consequence that the stationary state is achieved very quickly in a hotplate according to the new, objective invention.
The conclusion of this is that the advantage in this concept must be used in another way, due to the fact that the heat transfer from the liquid (heating water in the coil) to the liquid (filling liquid in the heating plate) in the order of 50 to 100 times larger than from the liquid to the air. The calculations show that when the heat transfer coefficient from the heating coil to the filling liquid in the heating plate is on the order of 600 W / m ² K, the advantage of the proposed concept is obvious.
In order to achieve this magnitude of the heat transfer coefficient, the flow rate of the filling liquid must reach a certain value around the coil. The flow rate of the filling liquid is in turn dependent on the circulation movement of the filling liquid in the heating plate. The circulation movement can only be caused if a certain flow dynamics in the Hotplate is satisfied. In order to ensure the favorable flow dynamics in the heating plate, the heating plate must be divided into the "warm area" and the "cold area". The term "warm area" is understood to mean the proportion of the area in which the heating coil is installed, and the "cold area" means the proportion of the heating plate area without a coil.

In a conventional hotplate, it is found to be optimal solution to lay the coil in every other imprint of Heizplattenschale so that the indentations in which the coil is embedded represent the channels in which an ascending flow forms and in the "tube empty" channels a descending flow (cold column) forms. It is important to note that the hot and the cold column must be separated from each other so that it does not come to the mixing of the hot and the cold stream. If it would come to mixing the two streams, the circulation movement of the filling liquid comes to a standstill and the heat transfer from the heating coil to the filling liquid comes to break. In this case, the concept loses its meaning.

The calculations show that the "warm area" and the "cold area" must be in a certain ratio to each other to ensure an optimal circulation movement of the filling liquid. According to calculations, this ratio should be in the range of (3 - 4.5): 1.

There is also the requirement that the heating power of the hot plate is as high as possible. Since these two conditions are contradictory, there is always an optimal solution that satisfies both conditions. Calculations show that the ratio of the heating surface of the heating plate to the heating surface of the coil should be (3.5-5): 1.

For the purposes of this invention, it is that the tube of pipe ∅ 10 x 0.5 mm made of steel, copper, VA, aluminum or other good heat conducting material is used. This tube can withstand a pressure of up to 70 bar, which makes it possible to use these radiators in high-rise buildings and especially to mention that these radiators can be used where aggressive media in the heating system are present. Although you can use the coil with other diameters, but again two contradictory demands are made, on the one hand, the flow resistance in the coil (the corresponding to the coil one larger diameters have) and on the other hand, the thickness of the usual hotplate which is usually limited to 16 -20 mm.
In order to maintain the circulation movement of the filling liquid in the heating plate, it is important that in the ascending channel, the channel cross-section is large enough so that the flow resistance can be kept low. It is also important that the cross-sectional conditions, ie channel cross-section to the pipe cross-section must be in a certain ratio to each other in order to meet the above requirements.
The calculations show that this ratio must be in the range (1,7 - 2,5): 1.

The question immediately arises: Why does one need such a thing? The answer is quite clear. The shell in the usual Heizplattenproduktion is made of sheet metal (1.2-1.25 mm). The two trays (a heating plate) measuring 600 mm x 1000 mm weigh approx. 11.52 kg - 12 kg.
According to the concept of the present invention, ie a heating plate with built-in tube according to the above explanations, the shell can be made of sheet metal 0.5 mm and accordingly weighs a hot plate only 4.8 kg.
For example, for a hotplate (1000x600mm) a coil of about 10 -12m in length is required, which is made of a tube Ø 10 x 0.5mm. The weight of the coil is 1.19 kg and thus the total weight of the heating plate is 5.99 kg - 6 kg.
Assuming that the coil is installed in a standard hot plate with a wall thickness of 0.5 mm, it is easy to calculate that it saves 12 kg of steel per radiator.
In view of rising steel prices on the world market, the new solution offers an excellent opportunity for cost-effective production of panel radiators.
The other option is to make the coil in "Queranordnug", eg to install the pipes in a horizontal arrangement, wherein the height of the coil assumes approximately half the height of the heating plate. At the two ends of the coil each have a "U-profile" attached to the gravity flows in the rising and in the to separate sloping area from each other, so that a mixing of the partial flows does not occur.

As a "sub-variant" of this solution, it is possible that the coil is mounted only in one half of the heating plate, the "warm half" - (half of the heating plate in which the coil is placed) of the "cold half" by means of a "U-profile" or an "L-profile" are separated so that the cold and the warm flow are not mixed together.

To stiffen the shell, embossments are provided over the entire shell surface, which hold the two shells together by spot welding.

Fig. 1

eine Prinzipskizze des erfindungsgemäßen Plattenheizkörper mit eingebauter Rohrschlange aus einem Rohr, das in versetzter Anordnung (in jedem zweiten Kanal ist das Rohr eingelegt) eingelegt ist.
Fig.1A zur Verdeutlichung der Fig.1
Fig.1B zur Verdeutlichung der Fig.1

Fig. 2

eine Prinzipskizze mit eingebauter Rohrschlange bis zu einer bestimmten Länge der Heizplatte, jedoch sind die Rohre in jedem Kanal eingelegt

Fig. 3

eine Prinzipskizze des erfindungsgemäßen Plattenheizkörpers mit eingebauter Rohrschlange in horizontaler Ausführung. Die Rohrschlange ist bis zu einer bestimmten Länge und bis zur einen bestimmten Höhe des Plattenheizkörpers eingebaut. Der Flächenanteil des Plattenheizkörpers der nicht mit der Rohrschlange bedeckt ist, dient als absteigender Teil bei der Gravitationsströmung innerhalb der Heizplatte.
Fig.3A zur Verdeutlichung der Fig.3
Fig.3B zur Verdeutlichung der Fig.3

Fig.4

eine Prinzipskizze des erfindungsgemäßen Plattenheizkörpers mit eingebauter Rohrschlange in horizontaler Ausführung. Die Rohrschlange ist über die ganze Höhe und bis zu einer bestimmten Länge des Plattenheizkörpers eingebaut. Der Teil der Fläche des Plattenheizkörpers der nicht mit der Rohrschlange bedeckt ist, dient als absteigender Teil bei der Gravitationsströmung innerhalb der Heizplatte.

Fig.5

Gemäß der Fig.5 ist die Möglichkeit dargestellt, daß die Rohrschlange an den beiden Enden der Heizplatte angebracht ist, d.h. in der Mitte der Heizplatte ist die abfallende Strömung und an den Enden der Heizplatte die aufsteigende Strömung. Mittels der U-Profile, die an den beiden Enden der Rohrschlange angebracht sind wird verhindert, daß es zur Überlagerung der aufsteigenden und absteigenden Strömung kommt.

Fig.6

Gemäß Fig.6 ist die Gestaltung eines Plattenheizkörpers aus zwei Heizplatten und zwei Lamellen dargestellt, wobie die Lamellen von der Innenseite der Heizplatten durch Punktschweißen befestigt sind, sowie mit Befüllungs- und Verschlußschrauben und mit Versteifungsblechen versehen.
Fig.6A zur Verdeutlichung der Fig.6
Fig.6B zur Verdeutlichung der Fig. 6
Fig. 6C zur Verdeutlichung der Fig. 6
Fig. 6D zur Verdeutlichung der Fig. 6

The invention is illustrated by way of example in the drawings. Showing:

Fig. 1

a schematic diagram of the panel heater according to the invention with built-in coil from a tube in an offset arrangement (in each second channel, the tube is inserted) is inserted.
Fig.1A to illustrate the Fig.1
1B for clarification of Fig.1

Fig. 2

a schematic diagram with built-in coil up to a certain length of the heating plate, but the tubes are inserted in each channel

Fig. 3

a schematic diagram of the panel heater according to the invention with built-in coil in a horizontal design. The coil is installed up to a certain length and up to a certain height of the panel radiator. The area fraction of the plate heater which is not covered with the coil serves as a descending part in the gravitational flow within the heating plate.
3A to clarify the Fig.3
3B to illustrate the Fig.3

Figure 4

a schematic diagram of the panel heater according to the invention with built-in coil in a horizontal design. The coil is installed over the whole height and up to a certain length of the panel radiator. The part of the surface of the plate heater which is not covered with the coil serves as a descending part in the gravitational flow inside the heating plate.

Figure 5

According to Figure 5 , the possibility is shown that the coil is mounted at the two ends of the heating plate, ie in the middle of the heating plate is the sloping flow and at the ends of the heating plate, the rising flow. By means of the U-profiles, which are attached to the two ends of the coil is prevented that it comes to the superposition of the rising and falling flow.

Figure 6

According to Figure 6 , the design of a plate radiator of two heating plates and two fins is shown, wherein the fins are fixed from the inside of the heating plates by spot welding, and provided with filling and sealing screws and with stiffening plates.
6A to illustrate the Fig.6
6B for clarification of FIG. 6th
6C for clarification of FIG. 6
6D for clarification of FIG. 6

According to Fig. 1 , the coil is arranged so that the heating tube 17 is inserted in each second channel 18 . The channels 18 are ascending, since the circulating water is warmed up by the heating tube 17 and rises high. By the cooling of the water in the descending channels 19 , a circulating movement of the water is caused in the hot plate, in the way that always alternately a channel 18 ascending and a channel 19 next to it is descending. This solution offers an excellent opportunity in radiator production to produce the radiators from thin sheet metal and you hardly need to change anything on the production line. Only the extra custom-made coils have to be inserted between two trays and the hot plate must be closed by spot and seam welding. The potential for saving material in such an embodiment is enormous.

According to Figure 2 , the coil is installed up to a certain length of the heating plate, wherein in each channel 18, the heating tube 17 is inserted and the whole, covered with coil snake area is considered ascending and the tubeless area 19 is considered descending. This causes a circulating movement of the heat transfer medium (eg, water mixed with cryoprotectant) across the height of the hot plate.

According to Figure 3 , the possibility is shown that the shells are not made with embossed channels, but with round (circular) indentations (Figure 3A) which allow the two shells are firmly connected to each other by spot welding and the heating coil in a horizontal arrangement is installed between the two shells. The indentations 20 hold the spiral and position the spiral. At the two ends of the coil, the U-profiles 21 are mounted, which prevent the rising and the falling stream 19 a mix and thereby the circulation movement of the water is impaired. On the surfaces of the heating plate, the slats can be attached by spot welding, which intensify the heat transfer to the outside. In this variant, the heating plate is partly covered over the height with the coil and partly over the length. In this way, the entire Heizplattenfläche is divided on the heating and cooling surface.

4 shows a schematic diagram of the panel heater according to the invention with a built-in tube coil is shown in a horizontal design. The coil is installed over the whole height and up to a certain length of the panel radiator. The area ratio of the panel heater which is not covered with the coil serves as the descending portion 19a.
In the gravitational flow within the heating plate, the coil is mounted to a certain length of the heating plate, wherein in the channel 18a, the coil is inserted and the whole, covered with the heating coil area, as ascending 18a and the roehrere area 19a , as descending. This causes the circulating movement of the filling liquid over the length and height of the heating plate.

According to Figure 5 , the possibility is shown that the coil is attached to the two ends of the heating plate, ie in the middle of the heating plate is the sloping flow 19a and at the ends of the heating plate, the rising flow 18a. The U-profiles 21 prevent the superposition of the two flows. Heating supply and return connections are mounted on different sides of the heating plate.

According to Figure 6 , for example, the design of a panel radiator 24 with two heating plates 25 and two fins 26 is shown. The design of a complete radiator corresponds to the embodiment according to FIG. The heating plate 25 is factory-filled with the Wärmeübertragungsflüßigkeit and closed airtight after filling by means of Verschlußschrabe 27 . Before the closing of the heating plate 25 , the air is partially evacuated (by means of a device for vacuum generation), so that it does not come to pressure build-up in the expansion of the heat transfer medium in its heating in the heating plate 25 . The radiator 24 is factory-filled for distribution. When filling the heating plate 25 with the heat transfer medium, a volume is provided which can compensate for the expansion of the heat transfer medium. For a radiator with the dimensions 600 x 1000 mm, the content of the filling liquid is approx. 3 kg. Chemically treated water is used as the filling liquid, with the addition of anti-freezing agent and an inhibitor against corrosion. The so filled heating plates 25 remain filled during the life of the radiator with chemically treated water. This excludes corrosion in the heating plate. For extreme conditions in the heating system, such as the presence of chlorides, the problem can be solved by making the coil of stainless material or of ordinary steel with a coating of the inner surface of the coil with a corrosion resistant agent.
Assuming that a conventional radiator with the dimensions of 600 x 1000 mm weighs 39.87 kg (two hot plates + two fins, eg Vogel and Not) and the radiator according to this invention is 12 kg lighter, it can be concluded that the radiator of the same size according to this invention filled with the filling liquid is only 27.87 kg heavy. It is obvious that additional transport costs will be saved.

Claims (12)

The plate radiator consists of one or more heating plates, characterized in that a coil (17) is installed in the embossments of the usual hot plate or other type of heating plates in a vertical arrangement as a heating element, so that in the embossed channel (18) in which the coil (17) is embedded, an ascending (18) and in the adjacent channel (19) without a coil, a sloping flow is caused inside the heating plate. The surface portions in heating plate covered with the coil (17) and the area of the heating plate not covered with the coil (17) are in a certain ratio (3 - 4.5): 1 to each other, which is calculated determined by the theory of heat transfer and fluid mechanics. The panel radiator according to claim 1, characterized in that the coil (17) in each second indentation [the channel (18)] of the usual heating plate is inserted. The usual hot plate is made of sheet 0.4 to 0.8 mm thick. In the impressions of the heating plate, in which the coil is inserted, the rising flow forms and in the "empty" imprints, the falling flow of the filling liquid is formed. The panel radiator according to claims 1-2, characterized in that the coil (17) in each adjoining indentation [the channel (18)], which is in a vertical arrangement in the usual heating plate, is inserted to a certain length of the heating plate. The other part of the heating plate is not covered with the coil (17) . On the Heizplatteninnenfläche, which is covered with the coil (17) , an ascending flow and on the Heizplatteninnenfläche without a coil ("tube empty area"), a falling flow is caused. The area shares with and without coil are in a certain ratio (3 - 4.5): 1 to each other in order to achieve the optimum circulation flow and thus the largest heat transfer coefficients. The panel radiator according to claims 1-3, characterized in that the coil (17) is installed in a horizontal arrangement in a heating plate which is formed as a flat plate, with the possibility of installing the coil (17) in different areas within the heating plate in that the hotplate inner surface covered with the coil (17) is in a certain ratio (3 - 4.5): 1 to the area fraction of the hotplate which is not covered by the coil (17) . The separation of the heating surface, which is covered with the coil, from the heating surface without a coil, is carried out by means of two U-profiles or L-profiles (21) or another type, so that it does not mix the ascending (18a) and the sloping ( 18a) 19a) flow comes. If mixing of the rising (18a) and falling (19a) flows would occur, the circulation movement drops sharply and thus also the heat transfer from the coil (17) to the filling liquid in the heating plate. The panel radiator according to claims 1 - 4, characterized in that the two U-profiles (21) or L-profiles (21) which separate the flow around the coil (17) from the descending flow (19a) , over the whole Extend height of the heating plate; there remains only one gap for the deflection of the ascending (18a) into the descending flow (19a) open. It is thereby achieved that the falling column (19a) experiences a lower temperature, whereby the circulation speed of the Füllflüßigkeit increases and thus the heat transfer from the tube coil (17) is increased to the Füllflüßigkeit. The plate heater according to claim 1-5, characterized in that the cross section of the embossed in the heating plate channel (18) in a certain ratio to the pipe cross section of the coil (17) must be in order to achieve the optimum flow rates and the optimum heat transfer coefficient can. According to calculations, this ratio is (1.7 - 2.5): 1. The plate radiator according to claim 1-6, characterized in that the average radiator temperature of the Füllflüßigkeit with optimal design of the heating coil (17) by 2 - 6 ° C lower than the average temperature of the standard radiator and the heating power 85% - 98% of the standard radiator is. The panel radiator according to claims 1-7, characterized in that the heating surface of the heating plate is in a certain ratio to the heating surface of the coil (17) for optimum heating performance. The optimum heat output is achieved when this ratio is (3.5 - 5): 1. The plate radiator according to claim 1 - 8, characterized in that the length of the heating coil (17) [heating coil of tube, ∅ 10 mm outer diameter] in one piece, should not be more than 10 m (for conventional heating systems). For the maximum length of a radiator (radiator up to 3m long), two or more coils are connected in parallel in a heating plate. The panel radiator according to claims 1 - 9, characterized in that two or more heating plates can be assembled, wherein by means of the T-pieces (27) the heating coils (17) are interconnected. The coils (17) are embedded in a shell (25) and sealed air-tight with the second shell. The heating water is evenly distributed on two heating plates to the heating coils (17) which are embedded in the shells (25) . On the insides of the heating plates, the lamellae (26) are fixed by spot welding as standard. The panel radiator according to claim 1 - 10, characterized in that suitable for the transformation of the conventional Plattenheizkörperproduktion on the production of panel radiators with indirect heating the tube ∅ 6 mm to ∅ 14 mm diameter made of steel, copper, aluminum or other heat-conducting material because it meets all the fluid mechanics, heat transfer, and channel size requirements of conventional hot plate production. The panel radiator according to claim 1 - 11, characterized in that the finding is obtained that the coil (17) may not extend over the entire Heizplattenlänge. Only a part of the heating plate is covered with the coil (17) in which the ascending movement of the filling liquid is formed and in the part not covered with the coil (17) in the heating plate, a descending movement of the filling liquid is formed. These two partial surfaces in the heating plate are matched with one another (computationally) for each type of radiator. If a heating plate is formed as a flat plate, the internals are required, which separate the rising from the falling stream, so it does not come to mixing of the two streams. The built-in separating element extends over the entire height of the heating plate. In the distribution channel of the heating plate, the openings are provided, through which it comes to the deflection of the rising into the sloping flow.

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