DE102016113137A1 - Gas-fluid counterflow heat exchanger - Google Patents

Abstract

In a gas-fluid countercurrent heat exchanger (10) having a plurality of each inside an outer shell (24) arranged parallel to each other fluid channels (22) and a plurality within the outer shell (24) substantially parallel to each other gas channels (20), each at both ends of Gas or fluid distributors (12, 14) are supplied with gas or fluid, the gas channels (20) and the fluid channels (22) are also arranged parallel to each other with opposite main flow direction, wherein the gas channels (20) by a plurality, substantially parallel to the main flow direction in the outer shell arranged metallic fins (16) and limited by at least one thermally conductive with the fins (16) connected fluid channel (22) in at least two sub-channels (20a, b) are divided, wherein the at least one fluid channel either the subdivision completely or effected by means of the fluid channel outgoing additional subdivision fins.

Description

The present invention relates to a gas-fluid countercurrent heat exchanger according to the preamble of claim 1.

Regenerative gas-fluid countercurrent heat exchangers are well known and are used, for example, in the air conditioning industry for heat recovery purposes. Although the known heat exchangers are referred to as countercurrent heat exchangers, they are so-called cross-countercurrent heat exchangers in which fluid ducts and gas ducts ultimately extend transversely or intersecting one another.

The object of the invention is to improve a heat exchanger of the type mentioned in terms of the efficiency, the overall efficiency, the design effort and hygiene.

The solution of the above object is achieved according to the features of claim 1.

Advantageous embodiments are described in the dependent claims. According to the invention, in a gas-fluid countercurrent heat exchanger having a plurality of fluid passages arranged in parallel in an outer jacket and a plurality of gas passages arranged in parallel in the outer jacket, which are respectively supplied with gas or fluid at both ends by gas or fluid distributors Gas channels and the fluid channels also arranged parallel to each other with opposite main flow direction.

Thus, the heat exchanger according to the invention is a true countercurrent heat exchanger, which can achieve very high efficiencies of typically 90% and more due to the entanglement of gas and fluid channels described below.

The gas passages are delimited by a plurality of metallic lamellae arranged substantially parallel to the main flow direction in the outer jacket. By the fins, which are also e.g. may have a flächenvergrößernde wave or zigzag shape, so that registers are limited for the passage of gas, which are additionally limited at the end faces by the boundary surfaces of the outer shell.

According to the invention, these gas ducts are additionally subdivided into at least two subchannels by at least one fluid duct connected in a heat-conducting manner to the lamellas. That is, the one or more fluid channels represent at least one further boundary surface for the gas channels. The heat exchange takes place both over these boundary surfaces and over the lamellae.

In this case, the at least one fluid channel can either effect the subdivision completely or by means of additional subdivision fins emanating from the fluid channel. The additional subdivision fins preferably lie in one plane with fluid channels arranged in one layer, whereas the remaining fins run transversely to this layer, with all the fins also extending parallel to the main flow direction, as mentioned above. Overall, preferably substantially (apart from possible contact surface enlarging waveforms of the lamellae or round shapes of the boundary forming fluid channels) arise rectangular gas channels, which are limited either by fins / subdivision fins or by the walls of the fluid channels.

In general, a number n of subdividing fluid channels results in a number of at least n + 1 resulting divided gas channels.

In a preferred embodiment, swirl bodies are at least partially provided in the fluid channels. By the swirl body, the flow in the fluid channels is swirled and slowed down and thus improves the heat transfer performance.

In a preferred embodiment, the heat exchanger according to the invention can be disinfected particularly well by providing one or more feed devices in the middle region of the outer jacket, through which a disinfection medium, in particular a disinfectant foam or steam, can be introduced into all gas channels, so that the disinfection medium can be introduced into both Directions are flowing.

In one embodiment, the fluid channels may be formed as pipes having a substantially circular or elliptical cross-section, which are thermally conductively connected to the adjacent lamellae.

To improve the heat transfer, the lamellae - as already briefly mentioned above - surface enlarging, in particular wave-shaped.

The invention will be explained in more detail with reference to the embodiments illustrated in the drawings. Show it:

1 a schematic sectional view through a heat exchanger according to the invention;

2 a schematic sectional view of the erfindungsmäßen heat exchanger along the cutting plane AA of 1 ;

3 a schematic sectional view showing a bundle of fluid channels and their heat-conducting connection to the slats;

4 a schematic representation of an alternative embodiment with wavy blades;

4a a schematic representation of an alternative embodiment of the heat exchanger according to the invention with additional subdivision slats;

5 an embodiment in which four heat exchanger modules according to 1 stacked on top of each other (in section);

5a an embodiment similar to 5 with two stacked heat exchanger modules and additional display of disinfection / cleaning openings;

6 an embodiment in which two parallel fluid channels are provided in a heat exchanger, in sectional view;

7 a perspective view of a heat exchanger according to the invention;

7a a sectional view of the heat exchanger of 7 with inserted cleaning / disinfection lance;

8th - 10 further sectional views of a heat exchanger according to the invention; and

10a a schematic view of a cleaning / disinfecting lance for use in a heat exchanger according to the invention.

An inventive heat exchanger can be used for a variety of applications, for example in the air conditioning for heat recovery, in power plant technology, e.g. in combined heat and power plants, in heat pumps, in the fluid cooling of technical systems, in a Stirling engine, etc.

The heat exchanger according to the invention can be used in both directions, i. be used both for heating the gas flow with simultaneous cooling of the fluid flow as well as for heating the fluid flow with simultaneous cooling of the gas stream. Depending on the choice of material, various gaseous and fluid media are conceivable. The most common media combination is likely to be air / water.

According to 1 has a total of 10 designated heat exchanger a plurality of parallel metallic fins 16 on, for example, copper or aluminum od. Like. These slats 16 , in the 1 run transversely to the plane of the drawing, limit gas channels 20a , over which in the direction indicated by the double arrows main flow direction, a gas flow (for example, air) is performed.

The gas stream is in a distributor region, not shown, on the individual gas channels 20a divided, ie, a gas main stream is divided into several sub-streams. For this purpose, the heat exchanger 10 For example, integrated into a ventilation duct so that it is forced through.

The course of the fluid channels 22 can be seen from the sectional view according to 2 along the line AA of 1 , The in 2 illustrated fluid channel 22 has a substantially circular cross-section, which is chosen so that this is a substantially gas-tight barrier between the adjacent lamellae 16 forms, eliminating the space between the slats 16 in two - in 2 top and bottom arranged - gas channels 20a and 20b and the fluid channel 22 is separated. This arrangement is repeated for all spaces between the slats 16 according to 1 , so that a bundle or a layer of parallel arranged fluid channels 22 is realized.

On the edge is the heat exchanger 10 by the way of an outer jacket 24 Surrounded by the gas channels 22a , b up and down (referring to the illustration in 2 ), but at the end faces above and below the distribution pipes described in more detail below 12 . 14 Of course, passages for the gas inlet and outlet leaves.

Each fluid channel 22 is at both ends of the heat exchanger 10 of distribution pipes 12 respectively. 14 (see also 1 ) supplied with the fluid medium (eg water or other heat or refrigerant transporting liquid, such as oil or refrigerant, which divide the main stream of fluid into corresponding partial streams 12 respectively. 14 be like in 1 indicated by corresponding end-side closures, preferably at opposite ends of a (not shown) fluid supply or (also not shown) fluid discharge (also referred to as flow or return) connected, so that for all parallel fluid channels 22 Overall, approximately equal flow conditions result, which is also referred to as Tichelmann arrangement. This configuration causes a Self-regulating uniform flow through the fluid channels 22 ,

The distribution pipes 12 respectively. 14 are preferably designed and arranged such that the gas flow through the gas channels 20a , b above or below the fluid channels 22 not or as little as possible is affected.

The fluid channels 22 can continue inside with so-called. Swirl bodies 18 be provided, for example, a in 1 schematically indicated helical arrangement, which gives the fluid flowing through a rotational component and thus improves the heat exchange.

The gas channels 20a On the other hand, b preferably have no flow obstacles in order to ensure a laminar flow and a low gas differential pressure between the inlet and outlet of the heat exchanger 10 to effect.

In order to meet the principle of the countercurrent heat exchanger, gas and fluid channels have opposite directions of flow (ie, they form an angle of about 180 °), as in the 1 and 2 indicated by the arrows (the upper arrow in 2 refers to the gas channels and the lower arrow to the fluid channel (s)).

In particular, in the case of air cooling, it is known that atmospheric moisture can be precipitated on the walls of the gas ducts, which if necessary can be supplied to a drain (not shown) by means of a corresponding gradient.

In order to enable a simple disinfection, can in the region of the channel centers laterally of the outer shell 24 be provided selectively via a lance with disinfectant foam or steam actable openings (not shown).

As in 3 schematically shown, this points between the slats 16 arranged fluid channel bundles 22 preferably has a circular cross section through which the with 28 designated fluid can flow, possibly with a swirl body 18 induced turbulence. Alternatively, elliptical or rectangular shapes of the fluid channels would be 22 conceivable. As an alternative to swirlers, screens or nets or other flow obstacles can also be provided.

The heat transfer takes place on the one hand directly over the walls of the tubes 22 , On the other hand, the pipes are peripherally on both sides, eg by introducing a good heat-conducting metal (tinning, brazing, electrodeposition) to the with 26 marked points as optimal as possible heat-conducting with the slats 16 connected, so that the slats 16 participate in the heat transfer into the gas channels. The thermally conductive connection 26 At the same time it ensures a largely airtight separation between the upper and lower gas channels.

In an alternative embodiment, the slats each extend centrally above and below (based on the orientation in 3 ) from the fluid channels, ie, upwardly from the 12 o'clock angular position and downwardly from the 6 o'clock angular position of the substantially circular fluid channel. In this embodiment, the fins are interrupted by the fluid channels each. At the 3 or 9 o'clock angular positions, the fluid passages preferably abut one another (this embodiment is not shown in the drawings) and thus form the separation between the upper and lower gas passages.

As an alternative to the embodiment described above and not shown, as shown in FIG 4a represented between the fluid channels arranged in a layer 22 also a further lamellar connection by means of additional subdivision fins 16 ' be provided so that the fluid channels 22 the subdivision between the gas channels 20a b not completely self-assemble, as in the other embodiments, but together with those between the fluid channels 22 extending additional so-called subdivision slats 16 ' , These subdivision slats 16 ' therefore, run substantially parallel to the layer of the fluid channels 22 whereas the other lamellae 16 essentially transverse to this layer. This results in a substantially grid-shaped grid.

In a schematically indicated alternative embodiment according to 4 can the slats 16 have a waveform to increase the heat transfer into the gas channels (or from the gas channels) due to the area increase. Although this may slightly affect the laminarity of the gas flow, this measure can reduce the flow resistance in the gas ducts by making the gas ducts shorter than non-corrugated fins 16 can be dimensioned.

Alternatively, triangular, sawtooth or rightwave-shaped contoured lamellae 16 conceivable.

In the 5 and 6 Embodiments are shown in which several of the described heat exchangers are stacked as a modular sandwich, wherein a plurality of parallel bundles or layers of fluid channels 22a -D are provided. It is in 5 an embodiment shown in which each heat exchanger still has a "separate" housing shell, so that in each case two gas channels adjoin (resulting in 2 gas channels per fluid channel), whereas in 6 these gas channels to a single gas channel 20b are united, so that a total of n + 1 gas channels result in n fluid channels. Thus, in both embodiments, at least n + 1 gas channels are present in the case of n fluid channels.

Partitions between gas ducts, as in the embodiment according to 5 , are statically less stressed and can possibly also be realized by means of a solid film.

In 5a is one too 5 similar embodiment with two bundles or layers of fluid channels 22a , B, wherein additionally provided in the housing shell and possibly closable openings 32 for introducing a cleaning or disinfecting lance are shown.

In 7 contains a perspective view of a heat exchanger according to the invention 10 with a bundle or layer of fluid channels 22a , The fluid channels 22a are with the vertical in the drawing slats 16 soldered so that the gas channels 20a , b each have a rectangular cross-section, ie, the curves of the substantially circular fluid channels 22a are approximately equalized with a metallic material to the gas channel. Schematically also the distribution pipes 12 respectively. 14 represented for the fluid.

In 7a is a sectional view through a heat exchanger 10 corresponding 7 shown by which through openings 32 two cleaning or disinfecting lances 34 are introduced, which in turn nozzles 36 have, through which a cleaning or disinfecting agent can be sprayed to clean or disinfect the gas ducts.

In 8th is a schematic sectional view through the two outer connection areas of a heat exchanger designed according to the invention 10 illustrated, wherein the sectional plane of a bundle or a layer of fluid channels 22a and distribution pipes 12 and 14 cuts; over here are with 20a designated gas channels.

In 9 is another schematic sectional view of a heat exchanger according to the invention 10 shown at the likewise (possibly closable) holes / openings 32 for a cleaning or disinfecting lance and a simplified swirl body or a spiral insert 18 are shown.

The use of the cleaning or disinfection lance 34 will be in the 10 and 10a illustrated. The lance 34 has nozzle-like openings at regular longitudinal intervals and at regular angular intervals 36 such that a cleaning and / or disinfecting agent passed through the hollow lance, in particular a disinfecting foam or steam in particular, is sprayed in a star shape, as in US Pat 10a shown.

As in the heat exchangers according to the invention 10 prefers no interference fit between fluid pipe 22 and lamella 16 is provided, the overall structure has a high inherent stability, with very good efficiencies of over 90% can be achieved by the countercurrent principle and the good internal heat exchange.

Claims (5)

Gas-fluid countercurrent heat exchanger ( 10 ) with several each within an outer jacket ( 24 ) parallel to each other fluid channels ( 22 ) and several within the outer mantle ( 24 ) substantially parallel to each other arranged gas channels ( 20 ), each at both ends of gas or fluid distributors ( 12 . 14 ) are supplied with gas or fluid, characterized in that the gas channels ( 20 ) and the fluid channels ( 22 ) are also arranged parallel to each other with opposite main flow direction, wherein the gas channels ( 20 ) by a plurality of substantially parallel to the main flow direction in the outer shell arranged metallic fins ( 16 ) are limited and by at least one heat-conducting with the slats ( 16 ) connected fluid channel ( 22 ) into at least two subchannels ( 20a , b), wherein the at least one fluid channel either causes the subdivision completely or by means of additional subdivision fins emanating from the fluid channel. Gas-fluid countercurrent heat exchanger ( 10 ) according to claim 1, characterized in that in the fluid channels ( 22 ) at least partially swirl body ( 18 ) are provided. Gas-fluid countercurrent heat exchanger ( 10 ) according to claim 1 or 2, characterized in that in the middle region of the outer shell ( 24 ) one or more feed facilities ( 32 ) are provided, through which a disinfecting medium, in particular a disinfectant foam or steam, can be introduced into all gas passages, so that the disinfecting medium flows in both directions. Gas-fluid countercurrent heat exchanger ( 10 ) according to one of claims 1 to 3, characterized in that the fluid channels ( 22 ) as pipes with substantially circular or in Are formed substantially elliptical cross-section, with the adjacent slats ( 16 ) are thermally conductively connected. Gas-fluid countercurrent heat exchanger ( 10 ) according to one of claims 1 to 4, characterized in that the lamellae ( 16 ) area enlarging, in particular wave-shaped.

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