EP2413045B1 - Heat exchange unit - Google Patents

Description

The invention relates to a heat exchanger unit, in particular a heat exchanger unit for hot water heating in a heating system, according to the preamble of claim 1.

For example, in heating systems, heat exchangers are used to supply service water, i. Drinking water, using the circulating in the heating system heating medium, preferably also to heat water. Such heat exchangers are usually designed as a plate heat exchanger and have four connections: an input for the heating medium, an output for the heating medium, an input for the hot water and an outlet for the hot water. These connections must be connected to other hydraulic components and the heating system, which requires different connection elements. In addition, the assembly, i. the connection of the various parts of the system be quite expensive.

DE 20 2006 009 322 U 1 discloses an assembly of valve assemblies for the circuits of a solar heater. The arrangement has a plate heat exchanger to which various components, such as pumps, valves, etc. are attached via various connection fittings. For this purpose, a wide variety of components are to be combined with each other, so that the assembly and the connection with various system components is quite complex. This document discloses the preamble of claim 1.

It is an object of the invention to provide a heat exchanger unit which can be easily integrated as a preassembled unit in a heating system and is inexpensive to produce.

This object is achieved by a heat exchanger unit, in particular for use for domestic water heating in a heating system, having the features specified in claim 1. Preferred embodiments will become apparent from the subclaims, the following description and the accompanying figures.

The heat exchanger unit according to the invention is provided according to the invention especially for domestic water heating in a heating system, i. it may preferably be a service water heating unit of a heating system. Such a service water heating unit can have all the essential components required for domestic water heating and thus form a prefabricated structural unit, which can then be easily integrated into a heating system or a building. In that case, only connections to the heating system and possibly the pipelines of the building have to be made by the service water heating unit. In particular, such a service water heating unit contains a heat exchanger with the necessary connections and a circulating pump for conveying heating medium to the heat exchanger. In addition, sensors, possibly required valves and in particular a control device for controlling the hot water heating in the domestic water heating unit can be integrated so that it must be connected via their line connections in the ideal case only with the external piping and a power supply. The line connections include in particular an input and output for heating medium, an input and output for hot water to be heated and possibly a connection for a hot water circulation pipe.

The heat exchanger unit according to the invention has a heat exchanger, which is designed as a plate heat exchanger. Plate heat exchangers can be produced inexpensively, have in their interior large heat transfer surfaces between the two media and can be formed intrinsically stable, so that they can serve as a supporting element of the heat exchanger unit to which other system components can be attached. In this way, can be dispensed with a separate support structure.

In order to connect the heat exchanger with other parts of the system, a first connection fitting is provided, which is attached to a first fluid port of the heat exchanger. This fluid connection is one of the four above-mentioned connections of the heat exchanger, i. Input or output for the heating medium or input or output for the medium to be heated, in particular service water. The term connection fitting in the sense of the invention is to be understood as an element which can establish a connection of external system parts to the heat exchanger, in particular a fluid-conducting connection to at least one of the fluid connections of the heat exchanger. The valve does not necessarily have to contain valves or the like.

In addition to the first connection fitting, a second connection fitting is also provided according to the invention, which is also attached or attached to the heat exchanger. In this case, this second connection fitting does not necessarily connect to one of the fluid connections of the heat exchanger, i. This second connection fitting is not necessarily the hydraulic connection of other system components to the heat exchanger, but can only serve for the mechanical attachment of other system components to the heat exchanger.

In order to reduce the variety of parts and thus enable a cost-effective production of the heat exchanger unit, it is provided according to the invention that the first and the second connection fitting each have at least one identically designed base element which defines at least one flow channel in its interior. The fact that one and the same base element can be used in two different connection fittings on the heat exchanger, the number of required items is reduced. The base member has in its interior a flow channel, which is not must necessarily be used in the connection fittings, but such a flow channel may also be unused, for example, in the second connection fitting, for example, if this is used only for mechanical fastening of other components. In the first connection fitting, this flow channel is preferably connected to a first fluid connection of the heat exchanger.

The first fluid connection is preferably arranged on a first side of the heat exchanger and the second connection fitting on a second, in particular one of the first side opposite second side of the heat exchanger. The two opposite sides of the heat exchanger, to which the connection fittings are preferably arranged, are preferably the flat side surfaces of the heat exchanger, which extend parallel to the flow paths in the interior of the heat exchanger separating plates. That is, the connection fittings are attached to two opposite side surfaces of the plate stack. These side surfaces usually represent flat surfaces to which the other elements can be attached well. Therefore, the plate stack is so easy to insert into an enclosing substantially tubular housing from the open sides, with end plates closing the open sides of the housing. The connection fittings can be arranged on these end plates. The housing preferably has four side surfaces arranged at right angles to each other, but may also be shaped differently corresponding to the shape of the plates in the heat exchanger. The arrangement of the connection fittings on two sides of the heat exchanger ensures that the heat exchanger between the connection fittings forms the supporting element, which holds together the entire heat exchanger unit preferably without external support structures.

More preferably, at least one connection fitting having an additional connected to the base member connecting part, which has in its interior a flow channel, which is preferably connected to at least one flow channel in the base member. Such a connection part allows the simple production of the base element, since this may have a less complex shape and is completed only after its shaping by the additional connection part. This is particularly advantageous if the connection fittings and their base elements are made of plastic by injection molding. In addition, it is possible to provide different functionalities in two connection fittings despite an identical base element by attaching a further connection part in at least one connection fitting to the base element. The connection part defines a further flow path through the flow channel formed in the interior, which can be used to connect or fasten further hydraulic components. This flow channel in the interior of the connection part, may be in communication with a flow channel in the base element, but may also be formed separately, depending on the hydraulic requirements. Preferably, the connection between the base element and the connection part is realized by a plug connection, wherein, if necessary, a seal between the connection part and the base element is required for a connection of the flow channels.

Furthermore, at least one second fluid connection, which is connected to the second connection fitting, is present on the heat exchanger, wherein the first fluid connection is preferably arranged on a first side of the heat exchanger and the second fluid connection is preferably arranged on a second side of the heat exchanger. This is preferably a side facing away from the first side. As described above, all the fluid ports are preferably arranged at the end faces of the plate stack of the heat exchanger, which extending parallel to the plates inside the heat exchanger. By arranging the second connection fitting or its base element on the second fluid connection, the second connection fitting is thus used to hydraulically connect the second fluid connection of the heat exchanger to external components or lines. For this purpose, preferably the at least one flow channel in the interior of the base element of the second connection fitting is connected to the second fluid connection of the second heat exchanger.

The identical base elements of the first and second connection fittings have in each case at least two separate flow channels, wherein in the first connection fitting a first of the two flow channels is connected to the first fluid port and the second connection fitting with identical base element at least a second of the two flow channels with the second fluid connection is connected. That When using the same base element in the first and second connection fittings, different flow channels are used in each case to connect the first fluid connection and the second fluid connection of the heat exchanger to external lines or components. When the first and the second connection fitting are arranged on opposite end faces of the heat exchanger, the base element of the second connection fitting is preferably rotated 180 ° relative to the base element of the first connection fitting so that identical side surfaces of the base elements are opposite, preferably the side surface, which connection openings for Have connection with the fluid connections of the heat exchanger.

In the second connection fitting, the second of the two flow channels in the base element is preferably connected to the second fluid connection, while the first of the two flow channels is in the second connection fitting Base member is connected to a third fluid port of the heat exchanger, which is preferably located on the same side of the heat exchanger as the second fluid port. In other words, in the second connection fitting, the base element with its two separate flow channels serves to connect two fluid connections of the heat exchanger to external components. In this way, a simple hydraulic connection of the heat exchanger to two fluid connections is achieved by a component. These two fluid connections may, for example, be the outlet for the heating medium and a cold water inlet for hot water to be heated. The first fluid connection of the heat exchanger, which is connected to the base element of the first connection fitting, may preferably be the outlet for the heated fluid, in particular for heated service water.

The flow channel in the base element of the first and second basic fittings preferably branches, starting from a connection opening facing the respective fluid connection of the heat exchanger, to two line connections. That is, this flow channel is formed substantially T-shaped with a crossing point, from which extend three sections of the flow channel to three line connections, which are connected in this way. Preferably, in the first connection fitting a first of the line connections and in the second connection fitting a second of the line connections is closed. This can be done for example by a releasable closure element such as a plug or by an attached connection part, which simultaneously closes the corresponding line connection. Optionally, a seal between the attached element and the conduit connection may be arranged for sealing. Furthermore, a closure of a power connection by an adjacent wall of the heat exchanger, possibly with an intermediate seal is possible, so that an additional Closing element for closing the line connection can be omitted. By closing individual line connections to the base element, it becomes possible to use the same base element differently in the first and the second connection fitting, ie differently guided flow paths can be realized in the first and the second connection fitting, so that external components or pipelines on different sides of the base element or the respective connection fitting and can be connected to the flow channel in the interior of the base element. In this way, a flexibility of the connection options is still realized with minimal variety of parts.

According to a particular embodiment, one of the two line connections can be closed by a connection part which defines in its interior a flow channel which is not in communication with the line connection to be closed. In other words, even if the connection part also has a flow channel in its interior, it does not necessarily have to be connected to the flow channel of the base element to which this connection part is attached. Rather, the connection part can simultaneously close the line connection of a flow channel in the base element.

Furthermore, it is preferable for a receptacle for a sensor, in particular for a temperature and / or flow sensor, to be formed in at least one flow channel or flow path of the base element in the first and second connection fittings. Thus, the sensor can also be a combined temperature and flow sensor. These sensors are used for controlling or regulating the operation of the heat exchanger unit, in particular in order to control or regulate the supply of heating medium as needed. Characterized in that provided in the connection fittings or their base elements a corresponding receptacle for such sensors is, these sensors can be very easily with little installation effort in the heat exchanger unit. Although in each case a receptacle for such a sensor is provided in the base elements of the first and the second connection fitting, since they are of identical design, this does not necessarily mean that a sensor is also inserted in this receptacle. It is also conceivable that a sensor is inserted in the respective flow channel only in one of the connection fittings, while in the other connection fitting the recording is unused, possibly closed by a closure element.

More preferably, a third connection fitting is arranged on the heat exchanger, preferably on the side of the first fluid connection, which is connected to a fourth fluid connection of the heat exchanger. Such a fourth fluid connection may for example be the input for heating medium in the heat exchanger. The fourth fluid port is preferably spaced from the first fluid port, but preferably located on the same side or side surface of the heat exchanger. Thus, on the same side of the heat exchanger, the first and the third connection fitting can be spaced apart from one another such that further components, for example a circulation pump, can be arranged between the two. The third connection fitting may preferably have a base element which is different from the base element of the first and the second base fitting, but may optionally also have an identical base element.

The third connection fitting further preferably serves for attachment and connection of a circulating pump, wherein a flow channel in the interior of the third connection fitting connects a first connection of the circulating pump, for example the pressure connection, to the fourth fluid connection of the heat exchanger. For example, the circulation pump can serve heating medium in the heat exchanger or by a promote first flow path of the heat exchanger to heat with this a liquid, such as service water in a second flow path of the heat exchanger.

The circulating pump is also preferably connected to the second connection, for example the suction nozzle, with the first connection fitting, the circulation pump is further preferably connected to a second flow channel of the first connection fitting, which is not directly connected to any fluid connection of the heat exchanger and a connection to a Conduit connection of the connection fitting forms. This flow channel is preferably a flow channel formed in the base element of the first connection fitting. This is thus not used for direct connection of a fluid connection of the heat exchanger but only for connection of the circulation pump to provide a connection of external system components, such as piping to the circulation pump.

Particularly preferably, the first and the second connection fitting with optionally attached connection parts are designed so that they provide all the necessary line connections of the heat exchanger unit on one side, more preferably in a plane of the heat exchanger unit. In this way, the connection of the heat exchanger unit to external components or pipelines is simplified because an interface surface is created on the heat exchanger unit, on which all the line connections to be connected are located. The heat exchanger unit thus preferably has at least four line connections to the connection fittings, for input and output of the heating medium and input and output of the medium to be heated, in particular service water. Optionally, further connections may be provided, such as a connection for a circulation line.

The second flow channel in the first connection fitting preferably has a connection opening facing the heat exchanger, which is closed in the first connection fitting. The connection opening is preferably formed in the base element and is particularly preferably closed by the side wall of the heat exchanger, which faces this connection opening, wherein a seal between the side wall and the base element can be arranged. In this way, the opening can be very easily sealed by mounting the connection fitting to the heat exchanger. The remaining portions of the second flow channel then connect only the two remaining pipe connections of the flow channel and serve as a connection line for the connected circulation pump. At the same time, a connection opening of the first flow channel in the base element in the first connection fitting is preferably connected to a fluid connection of the heat exchanger. The connection opening of the first flow channel and the connection opening of the second flow channel are preferably in a plane next to each other, so that they can be connected either simultaneously with two fluid ports in a side wall of the heat exchanger or, if at the respective location no fluid connection is present, sealing on the side surface of the heat exchanger can come to rest.

According to a further preferred embodiment, a fourth connection fitting is provided on the heat exchanger, which is preferably fastened or attachable to the second connection fitting. In this case, the fourth connection fitting preferably has a base element which is identical to at least one base element of the third connection fitting. In this way, the base element of the third connection fitting can fulfill a dual function, ie be used in an identical manner as a base element of the fourth connection fitting. This connection fitting is preferably on the same side of the Heat exchanger as the second connection fitting located, preferably spaced therefrom. The first and the second connection fitting are, as described, preferably on opposite end faces of the heat exchanger, but more preferably on the same side edge of the heat exchanger, wherein the third and the fourth connection fitting are preferably located respectively on an opposite side edge. For example, the first and the second connection fitting in the vicinity of the top and the third and the fourth connection fitting in the vicinity of the bottom of the heat exchanger are respectively arranged on opposite end faces of the heat exchanger.

The fourth connection fitting is preferably directly connected to any fluid connection of the heat exchanger. It thus serves only the mechanical attachment of other components to the heat exchanger and not for establishing a hydraulic connection to one of the fluid connections of the heat exchanger.

Preferably, the fourth connection fitting serves the connection and the attachment of a second circulating pump to the heat exchanger. This second circulation pump may be, for example, a circulation pump for the process water circulation. It is possible that this second circulation pump is optionally attachable to the heat exchanger, in which case also the fourth connection fitting is preferably optionally attachable to the heat exchanger. That is, the fourth connection fitting is then attached to the heat exchanger when the second circulation pump is to be fastened. In this case, the fourth connection fitting does not directly produce a fluid-conducting connection from the circulating pump to a fluid connection of the heat exchanger, but can possibly only serve for the mechanical fastening of the circulating pump to the heat exchanger.

Thus, the second circulating pump is preferably fastened or fastened between the second and the fourth connection fitting, wherein a flow channel in the second connection fitting or in the base element of the second connection fitting preferably forms a flow-conducting connection from the second circulating pump to a fluid connection of the heat exchanger. This fluid connection of the heat exchanger is, for example, the service water inlet. Thus, this second circulating pump, when used as a circulation pump, can promote service water back to the service water inlet of the heat exchanger. In this respect, the suction nozzle of the circulation pump is preferably connected to a line connection of a flow channel of the second connection fitting. This flow channel need not be formed directly in the base element of the second connection fitting, but may also be a flow channel, which is formed in a connection part, which is attached to the base element of the second connection fitting. This flow channel preferably provides only a connection to a line connection to one side of the heat exchanger unit, to which then an external circulation line can be connected to the heat exchanger unit. The line connection is, as described above, preferably on one side, or in a plane with the other line connections for connecting the heat exchanger unit to external components such as pipes. The second connection of the circulating pump, preferably the pressure connection, is furthermore preferably also connected via a pipeline to a flow channel in the second connection fitting. The pipeline for connecting the second circulation pump to the second connection fitting is preferably held on the fourth connection fitting, wherein the flow path in this pipeline can lead through a flow channel in the fourth connection fitting. In this case, this flow channel may be formed in a base element of the fourth connection fitting, which is identical to the base element of the third connection fitting, or in an additional with the base element connected connector. The pipeline preferably leads to a line connection of one of the flow channels in the base element of the second connection fitting. This is a flow channel which is branched in a T-shape and has a second line connection, which is preferably used to connect a cold water line. From the two line connections, this flow channel leads to a connection opening, which is connected to a fluid connection of the heat exchanger. This fluid connection is preferably the input for the service water to be heated. In this way, both cold hot water to be heated and the circulated hot water can be fed back to the entrance of the heat exchanger.

Fig. 1

eine Gesamtansicht einer an einem Wärmespeicher angeordneten Brauchwassererwärmungseinheit,

Fig. 2

eine perspektivische Gesamtansicht der Brauchwassererwärmungseinheit gemäß Fig. 1,

Fig. 3

eine perspektivische Ansicht des Wärmetauschers mit einer Anschlussarmatur,

Fig. 4

eine Schnittansicht der Brauchwassererwärmungseinheit gemäß Fig. 2,

Fig. 5, 6

eine Brauchwassererwärmungseinheit gemäß Fig. 1, 2 und 4 ohne Brauchwasserzirkulationsmodul,

Fig.7

eine perspektivische Explosionsansicht der Brauchwassererwärmungseinheit mit Brauchwasserzirkulationsmodul,

Fig.8

eine perspektivische Ansicht der Brauchwassererwärmungseinheit mit montiertem Brauchwasserzirkulationsmodul,

Fig. 9

schematisch die Strömungswege im Inneren des Wärmetauschers gemäß Fig. 3,

Fig.

10 den Temperaturverlauf im Inneren des Wärmetauschers über den Strömungsweg,

Fig. 11

ein hydraulisches Schaltbild einer Brauchwassererwärmungseinheit,

Fig. 12

den Temperaturverlauf, welcher von einem Temperatursensor im Kaltwassereingang der Brauchwassererwärmungseinheit erfasst wird,

Fig. 13

schematisch die Datenübertragung von den Sensoren zu einer Steuereinrichtung,

Fig. 14

die Anordnung mehrerer Brauchwassererwärmungseinheiten 2 in einer Kaskadenanordnung,

Fig. 15

schematisch die Steuerung der mehreren Brauchwassererwärmungseinheiten gemäß Fig. 14 und

Fig. 16

schematisch den Regelkreis zur Regelung der Brauchwassererwärmungseinheiten.

The heat exchanger unit according to the invention will be described below by way of example with reference to a service water heating unit which represents such a heat exchanger unit. In the figures shows:

Fig. 1

an overall view of a arranged on a heat storage hot water heating unit,

Fig. 2

an overall perspective view of the hot water heating unit according to Fig. 1 .

Fig. 3

a perspective view of the heat exchanger with a connection fitting,

Fig. 4

a sectional view of the service water heating unit according to Fig. 2 .

Fig. 5, 6

a domestic water heating unit according to Fig. 1 . 2 and 4 without domestic water circulation module,

Figure 7

an exploded perspective view of the service water heating unit with domestic water circulation module,

Figure 8

a perspective view of the domestic water heating unit with mounted domestic water circulation module,

Fig. 9

schematically the flow paths in the interior of the heat exchanger according to Fig. 3 .

FIG.

10 the temperature profile inside the heat exchanger via the flow path,

Fig. 11

a hydraulic circuit diagram of a domestic water heating unit,

Fig. 12

the temperature profile which is detected by a temperature sensor in the cold water inlet of the domestic water heating unit,

Fig. 13

schematically the data transmission from the sensors to a control device,

Fig. 14

the arrangement of several service water heating units 2 in a cascade arrangement,

Fig. 15

schematically the control of the plurality of service water heating units according to Fig. 14 and

Fig. 16

schematically the control loop for controlling the domestic water heating units.

The exemplary heat exchanger unit is a service water heating unit 2 and intended for use in a heating system. In the example shown here ( Fig. 1 ) is the service water heating unit 2 to a heat storage 4, for example, a water storage, which stores heated by a solar system heating water attached. From the heat storage 4 of the heat exchanger 6 of the service water heating unit 2 is supplied with heating medium for heating domestic water. In Fig. 1 a housing surrounding the service water heating unit 2 is shown open, ie the front cover is removed. In the other figures, the service water heating unit 2 is shown without surrounding housing.

The central best part of the heat exchanger unit or service water heating unit 2 is a heat exchanger 6 in the form of a plate heat exchanger. About the heat exchanger 6 to be heated hot water is heated and discharged as heated hot water, for example, to supply in a house taps 7 to sinks, showers, bathtubs, etc. with hot water. To heat the service water, the heat exchanger is supplied with heating medium. It has two flow paths in its interior, as shown schematically in FIG Fig. 9 shown. A first flow path 10 is the flow path through which the heating medium is passed through the heat exchanger. The second flow path 12 is the flow path through which the service water is passed through the heat exchanger. Both flow paths are separated in a known manner by plates, via which a heat transfer from the heating medium to the hot water is possible.

The two outer plates 13 of the plate stack form two opposite side surfaces of the heat exchanger 6. At these side surfaces are the fluid ports 14 to 20 of the heat exchanger. 6 trained and are, as described below, attached connection fittings.

Through the inlet 14, the heating medium enters the heat exchanger 6 and through the output 16 again. The hot water to be heated enters the heat exchanger 6 at the inlet 18 and exits the heat exchanger at the outlet 20 again. As in Fig. 9 schematically illustrated, the heat exchanger is divided into three sections A, B, C. In the flow direction of the process water through the second flow path 12, the section A forms a first section, in which the first flow path 10 and the second flow path 12 are guided past each other in countercurrent. Ie. the hot water to be heated and the heating medium flow in opposite directions past the plates separating them of the heat exchanger. This has the effect that the cold service water, which enters the heat exchanger 6 at the entrance 18, is first heated by the already cooled exiting at the output 16 heating medium and then comes in the flow direction in the vicinity of ever warmer heating medium. The heat exchanger 6 has a second section B, in which the first flow path 10 and the second flow path 12 are then no longer guided in counterflow arrangement relative to each other, but are guided in a Mitstromanordnung, ie, the flows in the first flow path 10 and in the second Flow paths 12 are rectilinear in the same direction along the plates separating them or other heat-conducting separators separating them.

Between the first section A and the second section B, a reversal section C is formed, in which the relative reversal of the flow directions in the flow paths to each other is realized. In the example shown here, the sections A, B and C of the heat exchanger are integrated in a heat exchanger. It is to be understood, however, that the sections A and B could also be formed in separate heat exchangers and the direction reversal of the flows to one another in section C could be realized by a corresponding piping of the two heat exchangers.

By reversing the mitstromprinzip is achieved that overheating of the service water is prevented, since the exiting at the outlet 20 heated service water is not heated directly in the last section of its flow path 12 through the inlet 14 incoming hot heating medium, but by already slightly cooled heating medium. As a result, the maximum to be reached hot water temperature is limited. This is in Fig. 10 to recognize. In the in Fig. 10 shown diagram, the temperature T of the heating medium is plotted as a curve 22 over the path s and the temperature T of the service water is plotted as a curve 24 over the path s. It can be seen that the outlet of the service water is not in the range of the highest temperature of the incoming heating medium, insofar as a maximum temperature can be achieved, which is at the level of the temperature of the heating medium in the region of the output 20 of the process water from the heat exchanger.

On the plate heat exchanger 6, the input 14 for the heating medium, the output 16 for the heating medium, the input 18 for the hot water to be heated and the output 20 for the heated service water formed as fluid connections, to which in turn connection fittings are attached, which connects to manufacture further components and pipelines. At the output 20 for the heated service water, a first connection fitting 26 is attached. This connection fitting has a base element 28 which, in an identical configuration in the second connection fitting 30, is only rotated by 180 ° at the fluid connections of the heat exchanger 6 which form the outlet 16 and the inlet 18. This has the advantage that one and the same base element 28 can be used as the first connection fitting and as the second connection fitting and the variety of parts can be reduced.

In the base member 28, two separate flow channels 32 and 34 are formed. The flow channel 32 is T-shaped and leads to three connection openings 36, 38 and 40 (see sectional view in FIG Fig. 4 ). When using the base member 28 as the first connection fitting 26, the connection opening 36 is unused and closed by the wall of the heat exchanger 6, wherein between the base member 28 and the wall of the heat exchanger 6 at the connection opening 36, a seal 42 is arranged for sealing. The connection opening 38 forms the connection for connection to a supply line 44 which is connected to the heat accumulator 4 for the supply of hot heating medium. At the oppositely located connection opening 40 of the flow channel 32, a first circulating pump 46 is arranged on the base element 28 when used in the first connection fitting 26, which feeds the heating medium to the inlet 14 of the heat exchanger 6. For this purpose, a third connection fitting 48 is arranged at the input 14, which in an identical embodiment only rotated by 180 ° on the opposite side of the heat exchanger 6, as described below, can be arranged as a fourth connection fitting 50. Ie. The third connection fitting 48 and the fourth connection fitting 50 are also formed from at least one identical base element.

In the third connection fitting 48, a flow channel 52 is formed, which connects the pressure port of the circulation pump 46 with the inlet 14 of the heat exchanger.

The second flow channel 34 in the base element 28 is, as can be seen in the sectional view with reference to the second connection fitting 30, also T-shaped and has three connection openings 54, 56 and 58 on. In the first connection fitting 26, the connection opening 58 of the second flow channel 34 is closed, z. B. by an inserted plug. The connection opening 54 is connected to the outlet 20 of the heat exchanger 6, whereby a seal 42 is likewise arranged between the connection fitting 26 and the heat exchanger 6. Connection piece 60, which connects connection opening 58 to line connection 62 via a flow channel formed in the interior of connection piece 60, is connected to connection opening 56 of second flow channel 34 in first connection fitting 26. The line connection 62 is used for connection to a hot water line, through which the heated service water is discharged.

On the opposite side surface of the plate heat exchanger 6, which forms the supporting structure of the service water heating unit, the base member 28 is attached as a second connection fitting 30. Through the second connection fitting 30, the output 16 for the heating medium and the input 18 for the cold service water are connected to the external installation. At the output 16 of the heat exchanger closes at this 180 ° rotated arrangement of the base member 28, the connection opening 54 of the second flow channel 34 at. This second flow channel 34 establishes a connection to the line connection or connection opening 58, which forms the outlet of the cooled heating medium. At this connection opening 58, a line can be connected, which leads the heating medium back into the heat accumulator 4. At the in Fig. 2 In the embodiment shown in which, as described below, a circulation of the service water is provided at the same time, a line 64 is connected to the connection opening 58, which leads to a switching valve 66 which selectively connects the line 64 to the connections 68 and 70 , The terminals 68 and 70 are used for connection to the heat accumulator 4, these connections, for example can establish a connection to the interior of the heat accumulator 4 at different vertical position, so that depending on the temperature of the exiting the heat exchanger 6 heating medium this can be returned by switching the switching valve 66 at different vertical positions in the heat storage 4, there existing stratification of the heating medium maintain. The switching function is particularly advantageous if, as described below, a service water circulation module 74 is provided. The heating of the circulating service water requires less heat, so that the heating medium with higher temperature flows back into the heat accumulator 4.

The flow path 32 in the interior of the base element is connected to the inlet 18 in the second connection fitting 30 by means of the connection opening 36. To the connection opening 38, a cold water line 72 is connected to supply the cold service water. Through this line, the cold water then enters the entrance 18 in the heat exchanger.

The domestic water heating unit shown here can be used in two different embodiments, namely once with a service water circulation module 74 or even without this service water circulation module 74 Fig. 1 . 2 . 4 . 7 and 8th This domestic water circulation module 74 is arranged on the heat exchanger 6. The Fig. 5 and 6 If the service water circulation module 74 is not provided, the fourth connection fitting 50 is not required and the connection opening or the conduit connection 40 of the base element 28 of the second connection fitting 30 is closed by a plug. Also, the connection opening 56 of the flow channel 34 is closed in this case by a plug.

The service water circulation module 74 consists of a second circulation pump 76, which serves to circulate the service water in the hot water supply system of a building. For connection of the second circulation pump 76, a connection part 78 and a pipe 80 are provided. For holding the pump 76 on the heat exchanger 6, a fourth connection fitting 50 is arranged at the end of a side surface, which is identical to the third connection fitting 48 or has an identical base element. However, when used as a fourth connection fitting 50, the flow channel 52 is not used. On the base element of the third and fourth connection fitting, a receptacle 81 is formed, in which a connection element 82 is used, which is connected to a discharge nozzle of the circulation pump 76. The connection element 82 has a flow channel in its interior and connects to the tube 80 via it. The tube 80 is connected with its end facing away from the connection element 82 with the connection opening 40 of the flow channel 32 in the second connection fitting 30, wherein the connection opening 40 is then not closed by a plug. In this way, serving as a circulation pump circulating pump 76 can return a portion of the heated service water back into the flow channel 32 of the second connection fitting 30 and through its connection opening 36 in the inlet 18 of the heat exchanger. Ie. In the flow channel 32 of the second connection fitting flow supplied cold process water through the connection opening 38 and through the circulation pump 76 back conveyed hot water through the connection opening 40 together.

The connection part 50 is placed on the base element 28 of the second connection fitting 30 such that it engages with a closed connection piece 84 in the connection opening 56 of the second flow channel 34 and thus closes the connection opening 56, so that no additional plug is required for its closure in the second connection fitting 30 more required is. Incidentally, the connection part 78 is tubular and connects two connection openings 86 and 88 located at opposite ends. The connection piece 84 has no fluid-conducting connection to the connection between the line connections or connection openings 86 and 88. The port 86 is connected to the suction port of the second circulation pump 76, and the port 88 forms a port to which a circulation passage 90 is connected. By using the connection part 78 and a fourth connection fitting 50, which is formed with its base element identical to the third connection fitting 48, a second circulating pump 76, which constitutes a circulation pump, can thus also be fastened to the heat exchanger 6 serving as a supporting structure with a few additional parts be, and the circulation line via the circulation pump 76 are fluidly connected directly to the second flow path 12 in the interior of the heat exchanger.

In the base element 28 of the first and second connection fittings 26 and 30, a sensor receptacle 92 is formed in the flow channel 32, which can serve to receive a sensor. When using the base member 28 as the second connection fitting 30, the sensor holder 92, if no domestic water circulation module 74 is attached, closed. In the first connection fitting 26, a temperature sensor 94 is inserted into the sensor receptacle 92, which detects the temperature of the heating medium 6 supplied to the heat exchanger. When using the service water circulation module 74, a temperature sensor 96 is used in the sensor receptacle 92 of the base member 28 of the second connection fitting 30, which serves to detect a hot water request and whose specific function will be described below. In addition, the connection part 60 also has a sensor receptacle in which a sensor 98 is inserted. The sensor 98 is a combined temperature and flow sensor which determines the temperature and flow rate of the output 20 from the Heat exchanger 6 detected by the flow path 34 in the first connection fitting 26 emerging heated service water. It should be understood that the above-described temperature sensors 94, 96 may also be used as combined temperature and flow sensors.

On the one hand, the temperature of the outgoing service water can be detected by the sensor 98, and based on this temperature and the temperature of the heating medium detected by the temperature sensor 94, the required volume flow of the heating medium can be determined and the first circulation pump 46 can be operated accordingly. The required control or regulation for the circulation pump 46 is preferably integrated as control or control electronics in the circulation pump 46.

The sensors 94, 96 and 98 are connected via electrical leads 99 to a sensor box 100, which forms a data acquisition module. The sensor box 100 detects the data provided by the sensors 94, 96 and 98. The Sensorbox 100 provides the captured data as in Fig. 13 shown, the control unit 101, which is integrated in this example in the control electronics of the pump unit 46, available. For this purpose, an output interface 102 is formed in the sensor box 100 and a corresponding input interface 104 is formed in the control unit 101. The output interface 102 and the input interface 104 are designed here as radio-frequency sections, which enable wireless signal transmission from the sensor box 100 to the control unit 101 in the pump unit 46. This allows a very simple connection of the pump assembly 46 and also the sensors 94, 96 and 98, since they do not have to be connected directly to the pump unit 46. Thus, the sensors 94, 96 and 98 can be connected and wired independently of the circulation pump 46 and the circulating pump 46 may also be easily exchanged, without affecting the wiring of the sensors. The control unit 101 in the circulation pump 46 preferably controls or regulates not only the circulation pump 46 but also the circulation pump 76, for which purpose the control unit 101 in the circulation pump 46 can also preferably communicate wirelessly with the circulating pump 76 or its control device. Thus, both circulation pumps 46 and 76 can be connected very easily, since only one electrical connection for the mains power supply is required. All communications for the controller are wireless.

Signal processing of the signals supplied by the sensors 94, 96 and 98 can also already be carried out in the data acquisition module 100 or the sensor box 100 in order to provide the required data in a predetermined format to the control device 101. The control unit 101 preferably reads out via the input interface 104 only the data currently required for the control from the output interface 102, so that the data communication can be kept to a minimum.

The control unit 101 preferably also takes over the control of the circulation, which is effected by the circulating pump 76 when using the domestic water circulation module 74, in such a way that the circulating pump 76 is switched off for circulation when the temperature sensor 94, a temperature of the supplied from the heat accumulator 4 Detected heating medium, which is below a predetermined limit. In this way it can be prevented that the heat accumulator 4 excessively cools due to the hot water circulation and the circulation can instead be exposed to times in which the heat supply to the heat accumulator 4, for example due to lack of solar radiation to a solar module, is too low.

The control unit 101 controls the operation of the circulation pump 46 in such a manner that the circulation pump 46 is first turned on when a heat demand for heating the process water is given, so that heating medium is supplied from the heat storage 4 to the heat exchanger 6. In the event that no service water circulation module 74 is provided, this heat demand for the service water is detected via the combined temperature flow sensor 98. When it detects a flow in the flow path through the fitting 60, i. H. a domestic water flow, this means that a tapping point for hot tap water is open, so that flows through the connection port 38 cold hot water and a heat demand for heating the hot water is given. Thus, the control unit 101 may operate the circulation pump 46 in this case.

In the event that the domestic water circulation module 74 is arranged, the hot water requirement can not be detected so that the sensor 98 also detects a flow due to the circulation, which is caused by the second circulation pump 76, when no tapping point for service water is opened. In this case, only the temperature of the service water leaving the heat exchanger 6 can be detected by the sensor 98 and, if it is below a predetermined limit, the circulation pump 46 can be switched to compensate for the heat losses due to the circulation in such a way that heating medium is supplied to the heat exchanger 6 and thus the circulated service water is heated.

In order to detect a hot water requirement in this case due to the opening of a tap 7, the temperature sensor 96 is used. This is how in Fig. 11 shown schematically, not exactly at the junction of the flow channel 32 in the base member 28, in which the portions of the flow channel of the connection openings 36 and 38 and 40 converge, but arranged on the basis of this Junction offset to the connection opening 38 out. Ie. the temperature sensor 96 is located in the portion of the flow channel through which the cold process water is supplied. When a tap for heated service water is opened, this leads to a flow of cold service water in this line section, so that, as in the lower curve in Fig. 12 it can be seen, a temperature drop is detected by the sensor 96 in the portion of the first flow channel 32, which extends to the connection opening 38. Upon detection of such a temperature drop, the control unit 101 turns on the circulation pump 46 for supplying heating medium. In Fig. 12 Several sequential service water requirements are shown, which in turn lead to a temperature drop and at the end of the request of heated service water again to a temperature rise, since the water in the line section, in which the temperature sensor 96 is disposed, then reheated.

The temperature sensor 96 is arranged in the second connection fitting 30 slightly above the junction at which the flow paths or sections of the flow channel 32 from the connection openings 36, 38 and 40 meet. In this way, it is ensured that the water circulates in the line section in which the sensor 96 is located when closing the tapping point for hot water and thus no flow through the circulating pump 46 from the connection port 40 to the inlet 16 again Hot water is heated slowly by heat transfer.

As already described above, the heat exchanger 6 forms the supporting element of the service water heating unit 2, to which the connection fittings 26, 30, 48 and optionally 50 with the pump 46 and optionally 76 and the sensor box 100 are attached. The service water heating unit 2 thus forms an integrated module, which can be installed as a prefabricated unit in a heating system or in a heating system. The circulation pumps 46 and 76 are arranged relative to the heat exchanger 6 so that their axes of rotation X extend parallel to the surfaces of the plates, in particular the outer plates 13. In order to secure the heat exchanger 6 with the components attached thereto in turn to the heat accumulator 4 or to another element of a heating system, a holding device in the form of a bracket 106 is attached to the heat exchanger 6. The bracket 106 forms on the one hand a fastening device for attachment to the heat accumulator 4 and also forms handle elements 108, which can be gripped by the entire domestic water heating unit 2, whereby an easy handling of the entire unit during assembly is possible.

Fig. 14 shows a special arrangement of domestic water heating units 2. In this arrangement, in order to satisfy a larger domestic hot water demand, four domestic water heating units 2 are cascaded in parallel according to the foregoing description. In the example shown, four service water heating units 2 are shown. However, it is to be understood that depending on the maximum service water requirement, fewer or more service water heating units 2 can be arranged in a corresponding manner. All service water heating units 2 are supplied in the example shown with heating medium from a common heat storage 4. The service water heating units 2 are identical except for one. The first service water heating unit 2, the one which in Fig. 14 is located adjacent to the heat accumulator 4 is, according to the embodiment, which in the Fig. 1 . 2 . 4 . 7 . 8th and 11 is shown, that is, this first service water heating unit 2 has a domestic water circulation module 74. The service water circulation module 74, which has the second circulation pump 46, is connected to the circulation line 90. This concludes at the farthest tapping point 7 to the DHW DHW line. In this way, heated service water can be circulated through the entire line system, which supplies the taps 7 with heated service water. The function of this service water heating unit 2 with service water circulation module 74 basically corresponds to the above description. The three other domestic water heating units 2 are formed without domestic water circulation module 74, ie as in the Fig. 5 shown.

Each of the domestic water heating units 2 according to Fig. 14 has a control unit 101 integrated in the circulation pump 46 and a separate sensor box 100. The individual control units 101 of the plurality of domestic water heating modules 2 communicate via radio interfaces 110 (see Fig. 13 ) together. In the first service water heating unit 2, the radio interface 110 can also be used for communication with the second circulation pump 76 and optionally the changeover valve 66. However, it is also possible that the switching valve 66 is controlled via the sensor box 100 and is connected to the sensor box 100 via an electrical connection line.

The control units 101 of all service water heating units 2 are formed identically and jointly carry out a control of the cascade arrangement, as they are based on Fig. 15 will now be described in more detail.

In Fig. 15 For example, the four service water heating units 2 are designated as M1, M2, M3 and M4. In the boxes below it is represented by numbers 1 to 4, the starting order of the domestic water heating units 2. The hot water heating unit 2, which has the position 1 in the starting order (in the first step M2) assumes a leadership function, ie is the leading Domestic hot water heating unit 2, ie the control unit 101 also causes the switching on and off of the other service water heating units 2.

When it comes to a dhw request, ie one of the taps 7 is opened, this is detected in the leading service water heating unit 2, as described above, by the combined temperature flow sensor 98. The service water heating units 2 marked M2 to M4 are those in Fig. 14 shown service water heating units 2 without domestic water circulation module 74. The service water circulation module 74 having domestic water heating unit 2 is the in Fig. 15 Module marked with M 1. This never assumes a leadership role. Now, if the leading module M2 detects a service water request in step A, this hot water heating unit 2 is first put into operation, ie the circulation pump 46 conveys heating medium to the associated heat exchanger 6. If now the Brauchwassererförderung is switched off from step B to C, this is leading domestic water heating unit 2 still warmed in step C. If now a service water request by opening a tap 7 takes place again from step C to D, therefore, again this leading service water heating unit 2 (M2) is put into operation. Now, if the hot water requirement increases by opening, for example, another tapping point 7, a next service water heating unit 2 is switched on in step E by the control unit 101 of the leading domestic water heating unit 2 (M2) of the domestic water heating unit 2 with the second position in the starting order (here M3) a signal sends for operation. Their control unit 101 then takes correspondingly the circulating pump 46 of this further service water heating unit 2 (M3) into operation in order to supply the heat exchanger 6 with heating medium.

If now the process water demand is switched off again from step E to step F, the service water heating unit 2 is switched off and the control units 101 of the individual service water heating units 2 set each other again the starting order. This is done in such a way that in the starting order now the service water heating unit 2, which was last switched on, takes over the first position and the first switched on domestic water heating unit 2, d. H. the hitherto leading domestic water heating unit 2, moves to the last position (here M2). The guiding function also changes correspondingly to the service water heating unit 2, which is now in the first position in the starting sequence (M2). In this way, a uniform use of the domestic water heating units 2 is ensured and at the same time ensures that the domestic water heating unit 2, which is first put into operation, preferably a domestic water heating unit 2, which still has residual heat. The domestic water heating unit 2 with the domestic water circulation module 74 always retains the last position in the starting order, d. H. This is switched on only at maximum load and serves only to warm the circulated service water. If a service water heating unit 2 is defective or fails, it will be completely removed from the starting order, ie. H. not started up at all. This is all done by communication of the identical control units 101 with each other, so that can be dispensed with a central control.

To shut off the domestic water heating units 2, if they do not heat hot water, is also an above based on the Fig. 1 to 13 unillustrated valve 112 is disposed in the input cold water input line DCW of each service water heating unit 2. This valve 112 is actuated via the sensor box 100 by the control unit 101. The valve 112 is preferably via an electrical Connected to the sensor box 100 and the control unit 101 sends via the input interface 104 and the output interface 102 to the sensor box 100 a signal to open and close the valve 112. When the valve 112 is closed, it is achieved that no hot water through the respective heat exchanger 6, so that cold service water is prevented from flowing through the heat exchanger 6 of the unused service water heating units 2 into the heated service water DHW output line.

Based on Fig. 16 Now, the temperature control of the heated service water DHW in a service water heating unit 2 according to the above description will be described. In the control unit 101, a controller 114 is arranged, which is set to a set temperature T _ref for the heated service water DHW. This setpoint temperature can be adjustable, for example, at the control unit 101 in the circulation pump 46. For this purpose, 46 controls may be provided on the circulation pump. Alternatively, via a wireless interface, such as infrared or wireless, a setting by means of a remote control or via a system automation done. From the setpoint value T _ref , the actual temperature T _{DHW of} the heated service water DHW detected by sensor 98 is subtracted. The difference is supplied to the controller 114 as a control difference .DELTA.T. This outputs a target rotational speed ω _ref for the circulating pump 76, with which the control of the circulating pump 46 takes place, so that it supplies a volume flow Q _CH of the heating medium to the heat exchanger 6. In this heat exchanger 6, the incoming cold service water DCW is then heated, so that it has the output side T of the heat exchanger 6 _DHW . This actual value T _DHW is then, as described, detected by the sensor 98 and fed back to the controller. Ie. According to the invention, the rotational speed of the circulation pump 46 and thus the volume flow Q _{CH of} the heating medium is regulated as a function of the starting temperature of the hot domestic water DHW.

In order to achieve a fast response, a feedforward control in the controller 114 is also provided in this example beyond. For this purpose, the volume flow of the service water is detected via the sensor 98 and this hot water volume flow Q _DHW the controller 114 connected as a disturbance. In addition, the temperature T _CHin of the heating medium 6 supplied by the circulation pump 46 to the heat exchanger 6 is detected by temperature sensor 94 and applied to the controller 114 as a disturbance variable. Taking into account these disturbances, the setpoint speed ω _{ref of} the circulation pump 46 is adjusted accordingly so that, for example, with colder heating medium and / or higher service water flow rate, the speed of the circulation pump 46 can be increased to more quickly reach the required setpoint temperature T _ref for the service water to be heated. Another disturbance or another parameter which has an influence on the hot water temperature T _DHW is the temperature T _{DCW of} the inflowing cold process water DCW. In the example shown, however, this is not applied to the controller 114 as a disturbance, since the cold water temperature is usually substantially constant. In the event that the cold water temperature can be subject to considerable fluctuations, however, it would also be conceivable to also connect the temperature T _{DCW to} the controller 114 as a disturbance variable.

LIST OF REFERENCE NUMBERS

2 -

Water heating unit

4 -

heat storage

6 -

heat exchangers

7 -

tap

8th -

casing

10 -

first flow path for the heating medium

12 -

second flow path for the process water

13 -

outer plates

14 -

entrance

16 -

output

18 -

entrance

20 -

output

22 -

Temperature curve of the heating medium

24 -

Temperature curve of the process water

26 -

First connection fitting

28 -

base element

30 -

Second connection fitting

32, 34 -

flow channels

36, 38, 40 -

Connection openings or line connections

42 -

seals

44 -

supply line

46 -

First circulating pump

48 -

Third connection fitting

50 -

Fourth connection fitting

52 -

flow channel

54, 56, 58 -

Connection openings or line connections

60 -

connector

62 -

line connection

64 -

management

66 -

switching valve

68, 70 -

connections

72 -

Cold water line

74 -

Hot water circulation module

76 -

Second circulation pump

78 -

connector

80 -

pipe

81 -

admission

82 -

connecting element

84 -

Support

86, 88 -

connection openings

90 -

circulation line

92 -

sensor recording

94.96 -

temperature sensors

97 -

junction

98 -

sensor

99 -

cables

100 -

Sensorbox

101 -

Control unit or control electronics

102 -

Output interface

104 -

Input interface

106 -

hanger

108 -

Hang reefs

110 -

Radio interface

112 -

Valve

DCW -

cold process water

DHW -

warm service water

CHO -

hot heating medium, heating medium supply

CHR -

cold heating medium, heating medium return flow

T _ref -

set temperature

T _DHW -

Temperature of the heated service water

T _DCW -

Temperature of the cold process water

T _CHin -

Temperature of the heating medium

Q _DHW -

Water flow

Q _CH -

Heizmediumvolumenstrom

ΔT -

Control difference

ω _ref -

Target speed

Claims (16)

1. A heat exchanger unit (2), in particular for the heating of service water in a heating installation, comprising
   a heat exchanger (6), which is formed as a plate heat exchanger, a first connector (26), which is attached to a first fluid connection point (20) of the heat exchanger (6), as well as a second fluid connection point (18) to the heat exchanger (6), which is connected to a second connector (30), which is fastened on the heat exchanger (6),
   characterised in that
   the first (26) and second (30) connector each comprise at least one identical base element (28) and the identical base element (28) of the first (26) and second (30) connectors each define, internally, at least two separate flow ducts (32, 34), in the first connector (26) a second (34) of the two flow ducts being connected to the first fluid connection point (20), and in the identical second connector (30) at least a first (32) of the two flow ducts being connected to the second fluid connection point (18).
2. The heat exchanger unit according to claim 1, characterised in that the first fluid connection point (20) is arranged on a first side of the heat exchanger (6) and the second connector (30) is arranged on a second side, in particular opposite the first side, of the heat exchanger (6).
3. The heat exchanger unit according to either claim 1 or 2, characterised in that at least one connector (26) comprises an additional connection part (60, 78) which is connected to the base element (28) and comprises, internally, a flow duct which is preferably connected to at least one flow duct (32, 34) in the base element (28).
4. The heat exchanger unit according to one of the preceding claims, characterised in that the first fluid connection point (20) being arranged on a first side of the heat exchanger (6) and the second fluid connection point (18) being arranged on a second side of the heat exchanger (6).
5. The heat exchanger unit according to one of the preceding claims, characterised in that, in the second connector (30), the first (32) of the two flow ducts is connected to the second fluid connection point (18), whereas the second (34) of the two flow ducts is connected to a third fluid connection point (20) of the heat exchanger (6), which third fluid connection point is preferably located on the same side of the heat exchanger (6) as the second fluid connection point (18).
6. The heat exchanger unit according to one of the preceding claims, characterised in that the second flow duct (34) in the first (26) and second (30) connector branches from a connection opening (54) facing the respective fluid connection point (20, 18) of the heat exchanger (6) into two line connections (56, 58), a first (58) of the line connections preferably being closed in the first connector (26) and a second (56) of the line connections being closed in the second connector (30).
7. The heat exchanger unit according to claim 6, characterised in that one of the two line connections (56) can be closed by a connection part (78) which defines, internally, a flow duct which is not connected to the line connection (56) to be closed.
8. The heat exchanger unit according to one of the preceding claims, characterised in that a holder (92) for a sensor (94, 96), in particular for a temperature and/or flow rate sensor, is formed in the first (26) and second (30) connector in at least one flow duct (32).
9. The heat exchanger unit according to one of the preceding claims, characterised in that a third connector (48) is arranged on the heat exchanger (6), preferably on the side of the first fluid connection (20), and is connected to a fourth fluid connection point (14) of the heat exchanger (6).
10. The heat exchanger unit according to claim 9, characterised in that the third connector (48) fastens and connects a circulating pump (46), a flow duct (52) inside the third connector (48) connecting a first connection point of the circulating pump (46) to the fourth fluid connection point (14) of the heat exchanger (6).
11. The heat exchanger unit according to claim 10, characterised in that the circulating pump (46) is connected via its second connection point to the first connector (26), the circulating pump (46) preferably being connected to a first flow duct (32) of the first connector (26), which first flow duct is not directly connected to a fluid connection point of the heat exchanger (6) and forms a connection to a line connection (38) on the connector (26).
12. The heat exchanger unit according to claim 11, characterised in that the first flow duct (32) is connected to a connection opening (36) which faces the heat exchanger and is closed in the first connector (26).
13. The heat exchanger unit according to any one of claims 9 to 12, characterised in that a fourth connector (50) is or can be fastened to the heat exchanger and preferably to the side of the second connector (30), the fourth connector (50) comprising at least one base element which is identical to a base element of the third connector (48).
14. The heat exchanger unit according to claim 13, characterised in that the fourth connector (50) is not directly connected to a fluid connection point of the heat exchanger (6).
15. The heat exchanger unit according to either claim 13 or claim 14, characterised in that the fourth connector (50) connects and fastens a second circulating pump (76).
16. The heat exchanger unit according to claim 15, characterised in that the second circulating pump (76) is fastened, or can be fastened between the second (30) and fourth (50) connector, a flow duct (32) in the second connector (30) preferably forming a fluid connection from the second circulating pump (76) to a fluid connection point (18) of the heat exchanger (6).

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