DE202012012919U1 - Pipe heat exchanger according to the countercurrent principle with parallel flow channels with increased heat-transferring surface - Google Patents

Abstract

Heat exchanger according to the countercurrent principle with parallel flow channels, which is essentially formed by layers of profiled plates provided one above the other, characterized in that the layers (1) each consist of two of the profiled plates (2), which are arranged in mirror image to one another.

Description

Technical area

The invention relates to a heat exchanger with a plurality of parallel flow channels, which is formed essentially by superimposed layers of profiled plates.

• – Wärmeübertragende Oberfläche
• – Strömungsform (Gleich-, Kreuz,- Gegenstrom)
• – Strömungsart (laminare, turbulente Strömung)
• – Möglichst geringe Vereisungsneigung bei tiefen Temperaturen
• – Querschnittgröße und die Aufenthaltsdauer im thermisch Relevanten Strömungsbereich
• – Wärmeleitwert des Tauscherplattenmaterials
• – Art des Mediums (gas- oder fluidförmig)
• – Strömungsgeschwindigkeit
• – Massenstrom der Medien

The increase in energy costs is increasingly forcing building planners to make the building envelopes of old and new buildings more energy-efficient, so that the natural air exchange suffers, which is also the case with so-called low-energy and low-energy buildings. Passive houses may be the case. In order to obtain a pleasant room climate, ventilation systems are installed, which means that controlled ventilation of the living space can be maintained. In turn, in order to have the lowest possible ventilation heat losses in such systems, so-called air / air heat exchangers, here physically designated as recuperative heat exchangers, which ensure that in cold seasons incoming cold outside air is heated by outflowing warm air, whereby possible little heat energy should be withdrawn from the respective building interior. It is necessary and expedient that both media are separated from each other via exchanger plates in order to ensure a hydraulic, thermal and hygienic separation of the media with higher temperature to the media at a lower temperature. The energy efficiency or quality of heat exchangers is expressed in terms of the heat recovery rate, the degree of heat recovery or the heat recovery level. In order to achieve the highest possible heat transfer, the following physical parameters are crucial for designing a heat exchanger or a heat exchanger:

• - Heat transferring surface
• - flow form (equal, cross, - countercurrent)
• - Type of flow (laminar, turbulent flow)
• - As low as possible the tendency to freeze at low temperatures
• - Cross-sectional size and length of stay in the thermally relevant flow area
• - Thermal conductivity of the exchanger plate material
• - type of medium (gas or fluid)
• - flow velocity
• - Mass flow of the media

Of the listed physical parameters, the first four criteria most affect the energy efficiency of a heat exchanger.

State of the art

In this context, various types of heat exchangers are already known.

For example, from [ DE 1 991 549 U1 ] a heat exchanger with a plastic tube bundle is known, which has an inlet at one end and at its other end an outlet, between which ends is the plastic tube bundle, which consists of a plurality of plastic tubes, which are each held at a distance from each other and their respective surfaces serve to heat exchange. The plastic tube are aligned parallel to each other.

Such heat exchangers are due to now corrosion-resistant plastic pipes in addition to the chemical industry in so-called room heaters used. Since in heat exchangers according to the countercurrent principle, the heat transfer from one to the other medium substantially dependent on the size of the available heat transfer surface of the tubes used, it is desirable to choose this surface as large as possible. In this known embodiment of a tubular heat exchanger, however, plastic pipes are provided with a relatively small outer diameter of 2 mm. The reason for this is that they can be wound up, which then reduces the rigidity of the individual tubes. Therefore, here the plastic pipes are involved in a wind-up to a tube bundle tube mat and the individual tubes are parallel to each other and held by a plurality of transverse bands at a distance from each other, and merged in the inflow and outflow, resulting in a gaseous media guide unfavorable, high pressure losses. Not least, only smooth plastic pipes are used in this known heat exchanger, whereby the available heat exchange surface is small or limited.

Furthermore, from the DE 39 28 558 A1 a so-called air / air heat exchanger with ribbed or corrugated pipes known, which consist of a temperature-resistant plastic. In these especially provided for agricultural cattle sheds air / air heat exchangers, the transfer of heat energy from warm air to cold air supply takes place in the thermodynamically unfavorable cross flow principle on the individual ribbed or corrugated pipes, which are clamped between two perforated grid plates and thereby each at a distance from each other in a stretched axially parallel fixed position can be brought. As a result, no special spacers between the tubes are required. Although by the Training this known heat exchanger with its rib or wave pipes, the heat output surface of the individual tubes compared to smooth tubes is increased, so this way and by the 90 ° deflection of the media in the inflow and outflow considerable pressure losses can not be avoided. The illustrated pipe density of the heat exchanger is low due to the bias on the perforated plates, since the pipe suspension increases the distance between the pipes with each other. If very small pipe diameters are used in a large number of pipes, a great deal of effort is required to produce the heat exchanger, since each pipe must be individually connected to a perforated plate. Economic mass production of this heat exchanger is not possible. Furthermore, a gas-tight connection of the tubes to the perforated plate with the proposed connection technique can be realized only with very unjustifiable high effort.

Finally, in the DE 43 33 904 C2 described a so-called channel heat exchanger, which is constructed of layered superimposed, meander-shaped profiled sheets through which a plurality of parallel flow channels are obtained. In this construction, the meandering profile plates are merely superimposed, whereby no frictional bond between the exchanger plates is achieved and a destabilizing "concertina effect" can occur under high mechanical loads. This in turn can lead to this heat exchanger with large mass flows of the pumped media does not have sufficient stability to remain dimensionally stable at high pressure differences and thus lose its given by the plate profile flow shape. Furthermore, the profiled sheets in the inflow and outflow regions of the heat exchanger must each be connected to one another in a complex manner in order to ensure a gastight connection of the profiled sheets to one another.

Object of the invention

The invention is therefore an object of the invention to provide a working countercurrent heat exchanger for fluid and gaseous heat exchanging processes, which should be distinguished over the prior art mainly by an economical production with simultaneous proper stability and improved heat recovery. Preferably, an improved flow behavior should be ensured for large media streams with high pressure differences.

Solution of the task

This object is achieved by the features of claim 1.

Advantages of the invention

This solution can be advantageously made of only one type of semi-finished cost-stable heat exchanger by two identical profile plates as semi-finished products, for example, from a thermoplastic such as PP, PE, PA or PS or from a metal sheet such as aluminum, stainless steel or copper in a thermoforming process or produced in the so-called twin sheet process (double deep drawing process for hollow body production) and then in the same manufacturing process of deep drawing mirror images of each other, non-positively welded or glued. This results in a complete heat transfer element having a plurality of gas- and fluid-tight flow channels is obtained, which forms the heat exchanger according to the invention arranged in several layers one above the other.

It is advantageous if the profile, that is, the respective cross section of the individual flow channels, is formed star-shaped. Furthermore, it is expedient to provide the star-shaped design of the pipe channels such that their star-shaped profile has angular or rounded tips, so that over the prior art, up to 50% larger heat-transferring surface is created.

However, the invention is not limited to this cross-sectional shape. Rather, all cross-sectional shapes are included, which lead to an enlargement of the heat-transferring surface.

Furthermore, a slight turbulent stimulation of the medium flowing through is generated by the special star-shaped design of the tube channels, whereby the thermodynamically unfavorable boundary layer to the profile wall requires no additional turbulence-generating indentations and a more significant increase in heat transfer performance takes place. Finally, since the pipe channels are arranged in the flow direction, the slightly higher pressure loss caused by the slightly turbulent flow is compensated or overcompensated by the profile geometry. Thus, an industrial simple and economical production of the profiles is possible.

According to the invention, two profile plates form a kind of exchanger plate with tube channels, which can advantageously be made air-tight and oxygen-tight from thermoplastics by the so-called twin-sheet method in a single operation. As a result, in such materials, for example, the application of ultrasonic welding with its complex and faulty steps can be omitted.

Furthermore, the profile plates according to the invention are also suitable for thermodynamic heat transfer processes with large pressure differences, when the profile plates are deformed for example from an aluminum, stainless steel or copper sheet with deep drawing presses on the special profile geometry and then connected to a mirror-image folding at their plate edges and plate webs non-positively.

This results in an extremely rigid heat transfer structure with a large specific surface, which is predestined for large pressure differences and high heat transfer performance.

Also, a further embodiment of the profile plates is possible, in each case a distance between the pipe ducts is provided as a drainage slot, so that when flowing through a gas, as is the case for example in the Abluftfortführung of air conditioning systems, the condensate formed during cooling through the drainage slots to can be removed to the heat exchanger bottom. As a result, a tendency to icing of the heat exchanger can be significantly reduced, whereby a higher efficiency, a longer service life with a larger temperature difference between the supply and exhaust air without the aid of external energy for heating the outside air is achieved.

Furthermore, not only in the winter months, the tendency to freeze can be reduced with the heat exchanger according to the invention, but also in the summer months, the cold energy from the room air to the warm outside air are transferred, whereas, in the known recuperative Entthalpiewärmeübertragern and regenerative Rotationswämeübertragern an undesirable moisture transfer in the summer months would take place, which would counteract a cooling and dehumidification of the warm outside air. As a result, the utility value of the recuperative Entthalpiewärmeüberträger and the regenerative rotary heat transfer in the summer months is severely impaired. By contrast, the heat exchanger according to the invention produces a heat transfer structure which, in the horizontal and vertical directions, constitutes a non-positive, rigid connection which was previously not possible with prior art heat transfer constructions.

Further details and advantages of the invention are described below with reference to embodiments illustrated in the drawings and explained.

drawings

Show it:

1 in perspective view a section of a heat exchanger with a plurality of superimposed layers of profile plates, which are arranged in pairs mirror images of each other, thereby star-shaped flow channels are formed;

2 a section according to 1 in which is indicated by arrows, as the heat exchanger is traversed by a hot and countercurrent of a cold medium;

3 a section after 1 in a kind of exploded view, and that before the profile plates in mirror image pairwise and the layers formed therefrom glued or welded together;

4 a section according to 1 However, the flow channels have a second star-shaped profile shape and are connected to adjacent star profiles non-positively via mechanical tongue and groove elements;

5 a section according to 4 without groove-spring elements, but with the formation of a distance between the flow channels as drainage slots;

6 a section according to 1 with a third star-shaped profile shape of the flow channels;

7 a section according to 1 with a fourth star-shaped profile shape of the flow channels;

8th a plan view of a heat exchanger with a V-shaped inlet and Auströmelement having Strömungsleitplatten for gaseous media;

9 a plan view of a heat exchanger with a rectangular inlet and Auströmelement having Strömungsleitplatten for fluid media, here for example, a hot water inlet and a cold water outlet with a 90 ° flow deflection;

10 a plan view of a heat exchanger with a rectangular inlet and Auströmelement having Strömungsleitplatten for fluid media, here for example for Cold water inlet and hot water outlet with a straight-line flow guide;

11 a perspective cutout of a heat exchanger with a V-shaped inlet and Auströmelement and transition elements for the flow channels; here for example with a shown exhaust air inlet and supply air outlet;

12 a perspective view of a complete gas heat exchanger;

13 a rotated by 90 ° heat exchanger according to 12 repeatedly strung together as a modular unit;

14 a perspective view of a fluid heat exchanger with a straight and a 90 ° angled flow guide;

15 a heat exchanger according to 14 , but with a double-sided flow guide and

16 a heat exchanger according to 15 , arranged several times as a modular unit against each other and behind each other.

Description of an embodiment

In 1 is a perspective view of a section of a erfindungsgmäßen heat exchanger shown, the three superimposed same layers 1 owns, each consisting of two same profiled plates 2 are composed such that in each case the profiled plates 2 are arranged mirror images of each other. Every plate 2 has centrally one or more (here three) semicircular channels parallel to the plate 2 run and with a star-like first profile shape 3 are formed, on the one hand increases the heat exchange surface and on the other the layers 1 stiffen. Due to the mirror-image pairwise arrangement of two profiled plates 2 arise due to the two semi-circular profile shapes 3 each tubular flow channels 4 What the profiled plates 2 every layer 1 at their mutual margins - referred to with 5 - Glued together, but this can also be done by a welding process.

2 is comparable to 7 Here, as an example, only time is spent as a heat exchanger according to the invention can be flowed through, with a warm medium (arrows 6 ) and in countercurrent with a cold medium (arrows 7 ). This flow is transferable to all figures below. For illustration purposes, there are the arrows 6 ; 7 been omitted.

A gas- and fluid-tight connection of the pairs of mirror-image arranged profiled plates 2 takes place at connection points 8th , as well as in 3 this can be done by gluing or welding.

Alternatively, in 4 the flow channels 4 with a second profile shape 9 shown, which has a star-shaped cross-section with angled peaks <90 °. At least the two outer, each vertically abutting flow channels 4 are here via a positive mechanical tongue and groove connection 10 connected with each other.

Furthermore, it is possible as in 5 shown that between the flow channels 4 drainage slots 11 be provided so that possible condensate drain and thus no icing at low temperatures can occur.

In the 6 and 7 are as a further alternative, a third star-shaped profile shape 12 and a fourth star-shaped profile shape 13 shown, the profile shape 12 consists of a star-shaped cross-section whose tips are rounded and formed with a straight Entformstrecke, whereas the star-shaped cross section of the profile shape 13 only has rounded tips.

The 8th shows a heat exchanger according to the invention in plan view with the end face of a v-shaped inlet and outlet 14 and 15 , wherein the flow may also be provided vice versa. In the inlet and outlet elements 14 and 15 there are flow baffles 16 and flow deflection plates 17 and in the middle a Einschiebenut 18 for insertion of a possible media partition. The housing of this heat exchanger is with 19 designated.

In 9 is the heat exchanger according to 8th shown in plan view, but with a rectangular inlet and outlet 20 and 21 , in which bent flow baffles 22 are provided. This construction is suitable, for example, for a fluid medium such as water, that is, this enters the heat exchanger through the inflow 20 in and out of this through the discharge element 21 again, with the kinked flow baffles 22 cause a 90 ° flow deflection.

Another alternative is in 10 shown, and that is again the top view of the heat exchanger according to 9 shown, but here are the front side rectangular inlet and outlet 23 and 24 with fan-shaped Strömungsleitplatten 25 provided, which open into a centrally arranged inlet and outlet opening. In the 10 shown arrows 23 and 24 , which also identify the rectangular elements, at the same time indicate the direction of a possible media flow, that is, for example, the arrow 23 corresponds to cold outside air and the arrow 24 corresponds to warm exhaust air.

In 11 is explosively shown a portion of a heat exchanger, with a V-shaped inlet and outlet 26 , which inflow segments 27 with a gas- and fluid-tight spring connection and inflow segments 28 having a gas and fluid-tight groove connection. Furthermore, it has outflow segments 29 with gas- and fluid-tight gluing or welding. The respective flow direction can be seen here from the indicated arrows. Finally, in this embodiment in the connection region of the structure of the flow channels Rampenübergansstücke 30 for the connection of the inlet and outlet element 26 intended.

Further shows 12 a simplified perspective view of a complete gas heat exchanger 31 with an inflow area 32 and a discharge area 33 , where in 13 this was used in a rotated position by 90 ° and multiple modular stringed together to form a composite total heat exchanger.

Regarding the 14 is in this schematic a fluid heat exchanger 34 represented in which a flow guide both straight - referred to 35 - Angled as well as 90 ° - marked with 36 - is provided. Against in 15 the same fluid heat exchanger 34 , as in 14 is shown, however, on both sides only a double straight flow guide - referred to 37 and 38 - owns.

Finally, in the 16 a modular whole unit 39 shown schematically, and constructed of the fluid heat exchangers 34 according to 15 ,

Industrial Applicability

Based on the fact that national and international buildings have to be built exclusively airtight in order to avoid the blatant, uncontrolled ventilation losses through leaking building envelopes, which can amount to up to 50% of heating energy requirements for low energy buildings, the future use will be controlled Ventilation devices expand. Highly efficient ventilation units with heat recovery can achieve performance figures of up to 25, which means that the 1 kilowatt-hour drive current for the fans can recover up to 25 kilowatt hours of heat energy. These performance figures are at the forefront in the field of mechanical energy systems, with which ecologically and economically very short payback times can be achieved.

Here is where the present invention proposes a suitable heat exchanger for the more and more required air exchange in living spaces, with which one uses, for example, the warmer used air of an interior to preheat countercurrently sucked cold outside air so that the available fresh air is not too cold flows into the interior, whereby heating energy can be saved. The heat exchanger according to the invention can perform this task well, since it can be produced rationally and therefore cost-effectively, and on the other hand, is designed stable enough for large volume flows, and also has a high efficiency.

For the production of the actual heat exchange tract of the heat exchanger according to the invention, a variety of a shaped semifinished product is sufficient, of which only two mold parts then have to be arranged in mirror image to each other in order to obtain a layer with parallel flow channels. Several of these pairings arranged one above the other, then already gives the main part of the heat exchanger. In addition, if then, the flow channels are still star-shaped in cross section, then you get an enlarged heat-exchanging surface that is 50 to 70% larger than conventional, for example, round or rectangular cross-sections.

LIST OF REFERENCE NUMBERS

1

 layer

2

 profiled plate

3

 first profile shape

4

 flow channel

5

 edge strips

6

 warm medium

7

 cold medium

8th

 junction

9

 second profile shape

10

 Tongue and groove connection

11

 drainage slot

12

 third profile shape

13

 fourth profile shape

14

 V-shaped inflow element

15

 V-shaped outflow element

16

 baffle plate

17

 Strömungsumlenkplatte

18

 insertion groove

19

 casing

20

 rectangular inflow element

21

 rectangular discharge element

22

 flow baffle

23

 rectangular inflow element

24

 rectangular discharge element

25

 baffle plate

26

 Inlet and outlet

27

 Einströmsegment

28

 Einströmsegment

29

 Ausströmsegment

30

 Ramp transition piece

31

 Gas heat exchanger

32

 inflow

33

 outflow

34

 Fluid heat exchanger

35

 straight flow guide

36

 angled flow guidance

37

 straight flow guide

38

 straight flow guide

39

 modular unit

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 1991549 U1 [0005]
• DE 3928558 A1 [0007]
• DE 4333904 C2 [0008]

Claims (10)

Heat exchanger according to the countercurrent principle with parallel flow channels, which is formed essentially by superimposed layers of profiled plates, characterized in that the layers ( 1 ) from two of the profiled plates ( 2 ) exist, which are arranged in mirror image to each other. Heat exchanger according to claim 1, characterized in that the profiled, mirror image arranged plates ( 2 ) are gas-tight and fluid-tight welded or glued together. Heat exchanger according to claim 2, characterized in that the profiled, mirror-image arranged plates ( 2 ) in areas of the adjacent flow channels ( 4 ) are welded or glued together. Heat exchanger according to claim 1, characterized in that the flow channels formed ( 4 ) mechanically via tongue and groove joints ( 10 ) form u. are positively connected with each other. Heat exchanger according to one of the preceding claims, characterized in that through the profiled plates ( 2 ) flow channels ( 4 ) has a star-shaped cross section (profile shape 3 ; 9 ; 12 ; 13 ) with five or more tips with an internal angle> 90 ° or <90 ° or are formed with rounded tips. Heat exchanger according to one of the preceding claims, characterized in that for a heat-emitting or receiving medium on the one hand, the star-shaped flow channels (profile shape 3 ; 9 ; 12 ; 13 ) And on the other hand formed by this also in cross-section star-shaped intermediate channels (profile shape 3 ; 9 ; 12 ; 13 ) and on both sides of the star-shaped flow channels ( 4 ) provided edge channels are provided. Heat exchanger according to one of the preceding claims, characterized in that between the star-shaped flow channels ( 4 ) Drainage slots ( 11 ) are provided. Heat exchanger according to one of the preceding claims, characterized in that at one end face of an inflow ( 14 ; 20 ; 23 ) and at the other end face an outflow element ( 15 ; 21 ; 24 ), the flow guide plates ( 16 ; 22 ; 25 ) and between the pipe channels and inflow elements ( 14 ; 20 ; 23 ) as well as outflow elements ( 15 ; 21 ; 24 ) Ramp crossings ( 30 ) be formed. Heat exchanger according to claim 8, characterized in that the inlet and outlet elements ( 14 ; 20 ; 23 ; 16 ; 22 ; 25 ) are V-shaped or rectangular. Heat exchanger according to one of the preceding claims, characterized in that a modular construction of the heat exchanger is provided, which allows that with such a heat exchanger modular units ( 39 ) are composed of several of these heat exchangers.

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