EP2413046B1 - domestic water heating unit - Google Patents

Description

The invention relates to a service water heating unit, which is intended for use in a heating system, with the features specified in the preamble of claim 1.

In heating systems usually also domestic hot water must be heated. For this purpose, it is known to provide either water storage in which the service water is heated, or to use heat exchangers in which the service water is heated in the manner of a continuous flow heater of a heating medium in a heating circuit.

In conventional heating systems, therefore, a system for domestic water heating in the heating system or the boiler is integrated.

In newer heating systems often several heat sources, such as a boiler and a solar system are used. In such, built of numerous components heating systems, it is difficult to integrate a system for domestic water heating in a particular part of the system.

DE 103 04 679 A1 discloses a heating and service water system, which is suitable for heating domestic water in a house. The system shows two pumps, one of which is a primary circuit pump, which delivers the heating water through the boiler and through the first side of the heat exchanger. A second pump delivers the process water through the second side or secondary side of the heat exchanger. This second pump conveys the hot water to be heated the heat exchanger back into a hot water tank. A circulation pump for circulation of the heated service water in a building is not provided in this system.

GB 2433101 A shows another heating system with a heat exchanger. A domestic water heating is not provided here. The individual components of the system are attached to a support plate, in which flow channels are formed. Although this leads to a compact structure, but requires a complicated structure Trögerplatte.

It is an object of the invention to provide a service water heating unit, which can be easily integrated into a heating system, integrated all essential for domestic water heating components in a unit, and is also simple and easy to assemble.

This object is achieved by a service water heating unit having the features specified in claim 1. Preferred embodiments will become apparent from the dependent claims, the description and the figures.

In the hot water heating unit according to the invention is a unit in which the essential components for domestic water heating are integrated. This is in particular a heat exchanger, which has a first flow path for a heating medium and a second flow path for the hot water to be heated. The heating medium may preferably be water of a heating circuit, which is supplied from a boiler or for example from a heat storage. Further, the service water heating unit has a circulating pump for the heating medium, which is connected to the first flow path of the heat exchanger and is fixed to the heat exchanger. This circulation pump is used to supply the heating medium to the heat exchanger, wherein the supply of heating medium to the heat exchanger can be adjusted or regulated by switching on and off of the circulation pump and possibly speed control of the circulation pump, depending on the heat demand for heating the service water.

In addition, preferably still required sensors and a control unit for controlling the domestic water heating are integrated into the service water heating unit. Also possibly still required valves and / or other hydraulic components may be integrated into the service water heating unit, so that this represents a structural unit, which can be delivered pre-assembled and then integrated into a heating system. The domestic water heating unit preferably has outwardly only the necessary line connections for connection to external pipes, namely in particular an input for the heating medium, an output for the heating medium, an input for the hot water to be heated and an outlet for the hot water to be heated. The flow guidance in the interior of the service water heating unit is effected by pipelines and / or preferably integrated connection components or Connection fittings, in each of which one or more flow paths or channels are formed and which are connected to the heat exchanger. These connection parts or connection fittings can preferably be manufactured as components made of plastic by injection molding.

According to the invention a second circulation pump is attached or attachable in the domestic water heating unit to the heat exchanger beyond, which serves as a circulation pump for heated hot water. Such a service water heating unit then preferably has an additional line connection for connecting a circulation line or a plurality of circulation lines of a building to be supplied with service water. In the building, such a circulation line usually branches off at the removal point for the service water farthest from the service water heating unit, in order to allow circulation of the service water in the entire line system, so that it is always filled with heated service water and thus waiting times for the removal of service water a sampling point are avoided.

According to the invention, it is now provided that the circulation pump required for this circulation of the process water should not be installed separately in a heating system but rather integrated into the service water heating unit so that it can be part of a preassembled unit. In this case, the second circulation pump is attached or attachable to the heat exchanger, which thus constitutes a supporting element of the service water heating unit.

According to the invention, the second circulating pump can be permanently integrated as a circulation pump into the service water heating unit. Alternatively, it is also possible to construct the service water heating unit in such a modular manner that a second circulating pump, which serves as a circulation pump serves, is optionally attachable to the heat exchanger. For this purpose, corresponding connections or fastening receptacles are arranged on the heat exchanger or the connection fittings, which are connected to the heat exchanger, so that optionally a second circulation pump can be attached to these, if such a circulation pump is desired. The circulation pump can thus form a circulation module with the associated components, such as sensors and other connection parts, which can optionally be integrated into the service water heating unit, wherein corresponding interfaces and fastening elements for connecting this circulation module or its components are already present in the service water heating unit.

Preferably, the second circulating pump is connected in flow-guiding manner to the heat exchanger in such a way that the circulation line opens into the second flow path of the heat exchanger via the circulating pump so that circulated service water is led back into the heat exchanger and can be heated there. The integration of the second circulating pump, ie a circulation pump in the service water heating unit further simplifies the installation of the heating system, since no separate system parts, in particular no separate pump for hot water circulation in the heating system or in the building must be mounted, but as part of the preassembled service water heating unit with the other components required for domestic water heating can be easily mounted from the unit. Preferably, the control for the circulation, ie, the circulation pump and possibly required sensors is also integrated into the service water heating unit. The integration of control, pumps and required sensors in the service water heating unit has the additional advantage that the number of electrical connections to be made during assembly the domestic water heating unit is minimized, since preferably only a mains power supply must be made.

The first circulating pump is preferably connected with a first connection to the first flow path of the heat exchanger and with a second connection to a line connection for the heating medium. Thus, preferably, the suction nozzle of the circulation pump is connected to the line connection for the heating medium and the discharge nozzle to the first flow path of the heat exchanger. An external pipe, for example for connection to a boiler or a water reservoir, is then connected to the pipe connection. The line connection is preferably designed as a standardized interface, in particular as a plug connection or with a thread to produce a light connection to external pipelines.

The second circulating pump is preferably connected to a first connection to a line connection for a circulation line and to a second connection to a line connection for a service water line or to the second flow path of the heat exchanger. This means that the external pipelines, in particular a circulation line, only have to be connected to the line connections of the service water heating unit. The circulation pump and other necessary piping for hot water circulation are already integrated in the domestic water heating unit. These line connections are preferably designed as plug-in or threaded couplings in a standardized manner in order to produce a light connection with external lines. Particularly preferably, the second circulating pump, as described above, directly connected to the second flow path of the heat exchanger. Expediently, the discharge nozzle of the second circulating pump opens into the second flow path of the heat exchanger in order to circulate Lead the process water into the heat exchanger and heat it up again.

The heat exchanger is particularly preferably a plate heat exchanger. Such plate heat exchangers are inexpensive to produce, provide large heat transfer surfaces between the first and second flow paths inside, and are inherently stable, so that they can form the central supporting component of the service water heating unit, as described above. Thus, all other components such as connection fittings, connecting parts, circulation pumps, etc., can be attached to the heat exchanger, so that it is possible to dispense with an additional support structure. The plate heat exchanger is formed in a known manner as a stack of spaced plates, between the plates usually alternately drt first and the second flow path, so that the first and the second flow path in each case by a plate over which the heat transfer takes place from each other are separated.

The circulation pumps are preferably mounted on the heat exchanger so that the axes of rotation of the first and / or the second circulation pump extend parallel to the plates of the heat exchanger. This allows a particularly compact design of the domestic water heating unit by the pumps are aligned parallel to the plates of the heat exchanger.

More preferably, the first and the second circulation pump are arranged on two opposite sides of the heat exchanger. That is, the heat exchanger is located between the two circulating pumps and thus forms a central supporting component. By this arrangement, on the one hand, the connection of both circulating pumps is simplified with the heat exchanger as a supporting element, on the other a particularly compact design of the entire service water heating unit can be realized.

The opposite sides, to which the circulation pumps are attached, are preferably formed by the outer plates of the plate heat exchanger. In these plates, the connection openings of the two flow paths are preferably formed in the interior of the heat exchange, so that the circulation pumps can be connected to these from the sides flow leading and can be attached to these sides at the same time on the heat exchanger.

According to the invention, at the heat exchanger at the inlet of the second flow path, i. the flow path for the service water, a connection fitting mounted, which has a line connection for a service water pipe and is connected to a connection of the second circulation pump. The connection fitting thus has a T-shaped flow channel in the interior, from which a first leg extends to the line connection, a second leg to the circulation pump and a third leg to the connection opening or to the inlet of the second flow path of the heat exchanger. That the flow paths from the line connection and the second circulation pump are combined in the connection fitting and then open together into the inlet of the heat exchanger.

The line connection to this connection fitting is preferably provided for connection to a cold water line. In other words, the service water to be heated is supplied to the service water heating unit via this line connection. By the confluence of the flow channel of the second circulation pump is thus achieved that both the circulated service water from the second circulating pump Also, the supplied cold water are passed into the second flow path of the heat exchanger to be heated there.

More preferably, a temperature and / or flow sensor is arranged in a flow path in the connection fitting. These sensors can be used for controlling or regulating the domestic water heating unit. In particular, they may serve to determine if service water is requested in the system, i. a service water flow from the service water supply, i. a cold water pipe is given. In addition, they can detect the temperatures in order to adjust and / or regulate the supply of heating medium, in particular via the first circulating pump, and to keep the process water at a desired temperature.

Particularly preferably, a temperature sensor in the connection fitting mentioned is used to detect a service water requirement or the service water requirement. For this purpose, the connection fitting in a flow channel as described preferably has a first channel section or leg to the line connection and a second channel section or leg to the second circulation pump, which meet in a node. From this node branches off a third channel section or leg, which leads to the connection opening or the entrance of the heat exchanger. The temperature and / or flow sensor is preferably located in the first leg, ie the leg leading to the line connection, spaced from the node. This arrangement makes it possible to reliably detect the domestic water requirement based on the temperature in this channel section. This is particularly in connection with the hot water circulation advantageous because when using the hot water circulation, the hot water requirement, ie a pin of hot water at a sampling point due to a flow in the lines can not be reliably detected.

It can not be distinguished whether the flow is caused by the circulation or the opening of a faucet. When a temperature sensor or a combined temperature / flow sensor detecting the temperature is disposed in the passage portion to the piping port spaced from the node at which the circulation passage from the second circulating pump is located, temperature fluctuations can be detected that are safe to a service water request close. In the circulation mode, when no service water is tapped, the standing in this channel section water is due to its proximity to the leading to the second circulation pump channel section, through which the circulated hot water flows warm. Now, when hot water is drawn, flowing through the channel portion to the line connection supplied cold water and the temperature drops, whereby the pin can be reliably detected by hot water and then the first circulation pump for supplying heating medium to the heat exchanger can be put into operation by a control unit ,

According to a further preferred embodiment, a fastening element is attached to the heat exchanger, to which at least one pipe connected to the second circulation pump is attached. Such a pipeline can connect the second circulating pump with a line connection for connecting a circulation line or a connection fitting of the heat exchanger. Preferably, all the line connections of the service water heating unit lie on one side of the service water heating unit, more preferably in one plane, so that an interface surface is created at which all external lines are connected to the service water heating unit.

According to a particular embodiment of the invention, the second circulating pump is designed to be removable, wherein a connection fitting is provided for connection of the second circulation pump, which has a closable connection for the circulation pump. This configuration makes it possible to design the service water heating unit according to the invention modularly in such a way that the second circulation pump can optionally be used in the service water heating unit with possibly still necessary line connections as a circulation module. At least one connection fitting, which remains attached to the heat exchanger, regardless of whether the second circulation pump is attached or not, is preferably attached to the heat exchanger. The connection fitting may have further flow paths in the interior, for example, as described, establish the connection from a cold water line to the heat exchanger. By closing the connection for the second circulating pump, for example by means of a sealing plug or another removable closing element, it is then possible to easily attach the second circulating pump as a circulation module to this connection as required. By this configuration, the required variety of parts is reduced, since one and the same connection fitting can be used, regardless of whether the circulation module is provided or not. In addition, it is easily possible if necessary to retrofit the second circulation pump as a circulation module in the service water heating unit.

According to a further preferred embodiment, at least one sensor, in particular a temperature and / or flow sensor or flow sensor is provided, which is connected to a data acquisition module which has an output interface which is designed for communication with an input interface of a control unit of at least one of the circulation pumps. Preferably, several and in particular all sensors, which are provided in the service water heating unit, and possibly also external sensors are connected to this data acquisition module. This can be done for example via electrical connection cables. The data acquisition module then serves to communicate with the input interface of the control unit via a single output interface. In this way, the connection of the sensors to the control unit is simplified because they do not have to be connected directly to the control unit. The control unit preferably serves to control the service water heating unit, in particular by controlling at least one of the circulation pumps. Thus, in particular, the first circulating pump is controlled in such a way that it is turned on when hot water demand to supply the heat exchanger heating medium for hot water heating. In addition, the control unit may also include a control or regulation, in particular a speed control of the first circulating pump in order to adjust the flow rate of heating medium as needed based on the detected sensor signals can.

The control unit or control device is preferably integrated as control electronics at least partially into one of the circulating pumps, in particular the first circulating pump. This eliminates the need to connect and install a separate control unit, as it can be integrated directly into the electronics of the circulating pump unit. In particular, in this integration, the arrangement of the data acquisition module of advantage, since not all sensors must be individually connected to the control electronics of the pump unit, so that it does not have to be provided correspondingly many connections for individual sensors on this.

The input interface and the output interface are preferably designed as wireless interfaces, in particular as radio interfaces, so that one can completely dispense with a line connection to the control unit for connecting the sensors. So even a pump unit, in which this control unit is integrated, ideally requires only one electrical connection to the mains power supply.

The data acquisition module is preferably arranged as a connection and electronics unit in a housing, which in turn is also attached directly or indirectly to the heat exchanger as a supporting component of the service water heating unit.

Conveniently, a holding device is attached to the heat exchanger, which serves for fastening the service water heating unit and is preferably designed as a retaining bracket. The holding device is used for attachment, for example in a heating system, or a heat storage. It can be designed, for example, as a screw fastening or as a hook fastening, so that the holding device is designed, for example, such that the service water heating unit can be suspended on preassembled hooks on a heat accumulator or on the wall. The holding device is preferably bow-shaped designed as a headband. This has the advantage that the headband can simultaneously form handle elements on which the hot water heating unit can be taken for mounting, whereby the handling is simplified.

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.

Hereinafter, the domestic water heating unit will be described by way of example with reference to the accompanying drawings. In these 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 .

Figure 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,

Fig. 7

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

Fig. 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 accumulator 4, the heat exchanger 6 of the domestic water treatment unit 2 is supplied with heating medium for heating domestic water. In Fig. 1 a housing surrounding the domestic 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 in a known manner by plates from each other separated, 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, the fluid ports 14 to 20 of the heat exchanger 6 are formed and are, as described below, attached fitting 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. However, it is to be understood that the sections A and B could also be formed in separate heat exchangers and the direction reversal of the flows to each other 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 more Produce 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 a first connection fitting and as a 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 38, 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, as can be seen in the sectional view with reference to the second connection fitting 30, is likewise T-shaped and has three connection openings 54, 56 and 58. 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 shown embodiment, in which at the same time, as described below, a circulation of the service water is provided, to the connection opening 58, a line 64 is connected, which leads to a switching valve 66, which selectively connects the line 64 to the terminals 68 and 70 produces. The terminals 68 and 70 are used for connection to the heat accumulator 4, these connections can establish, for example, a connection to the interior of the heat accumulator 4 at different vertical position, so depending on the temperature of the emerging from the heat exchanger 6 heating medium this by switching the switching valve 66 at different vertical positions in the heat accumulator 4 can be returned to maintain existing stratification of the heating medium there. The switching function is particularly advantageous if, as described below, a service water circulation module 74 is provided. The heating of the circulated 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 show the arrangement without the domestic water circulation module 74. If the domestic water circulation module 74 is not provided, is the fourth connection fitting 50 is not required and the connection opening or the line 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 circulation pump circulating pump 46 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 48 is placed on the base element 28 of the second connection fitting 30 so 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 there is no additional plug for its closure in the second connection fitting 30 more is needed. 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 46 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 is also in the sensor receptacle 92 of the base member 28 of the second connection fitting 30 a Temperature sensor 96 is used, which serves to detect a dhw 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 detects the temperature and the flow of the heated service water leaving the outlet 20 from the heat exchanger 6 through the flow path 34 in the first connection fitting 26. 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 here designed as radio-frequency cells, which provide a wireless signal transmission from the sensor box 100 to the control unit 101 in the pump unit 46 allow. 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 replaced 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 storage 4 due to the hot water circulation excessively cools down and the circulation can be instead in times in which the heat supply to the heat storage 4, for example, due to lack of solar radiation to a solar module, too low, are exposed.

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 offset starting from this node to the connection opening 38. 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 domestic 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 domestic water heating unit 2, the one who 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 connects to the most remote 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 service water heating unit 2 which has the position 1 in the start sequence (in the first step M2) assumes a management function, ie the leading service water heating unit 2, ie its control unit 101 also causes the switching on and off of the further 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 M1 module. This never assumes a leadership role. If now detects the leading module M2 in step A a dhw request, 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 Brauchwassererfärderung 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 service water heating unit 2 (M2) of Domestic hot water unit 2 with the second position in the starting order (here M3) sends a signal to start 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 hot water heating unit 2, ie 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, ie this is switched on only at maximum load and serves, moreover, only to heat the circulating hot water. If a service water heating unit 2 is defective or fails, it will be completely removed from the starting order, ie it will not be put into operation 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 connected to the sensor box 100 via an electrical connection line and the control unit 101 sends a signal for opening and closing the valve 112 via the input interface 104 and the output interface 102 to the sensor box 100. When the valve 112 is closed, it is reached in that no service water flows 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 outlet 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 output side of the heat exchanger 6, the output temperature T _DHW has. 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

- Domestic water heating unit

4

- Heat storage

6

- Heat exchanger

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

- Exit

18

- Entrance

20

- Exit

22

- Temperature curve of the heating medium

24

- Temperature curve of the service water

26

- First connection fitting

28

- basic 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

- Changeover valve

68, 70

- Connections

72

- cold water pipe

74

- Domestic water circulation module

76

- second circulation pump

78

- Connector

80

- Pipe

81

- Admission

82

- Connection element

84

- Support

86, 88

- connection openings

90

- circulation pipe

92

- Sensor recording

94, 96

- Temperature sensors

97

- node

98

- Sensor

99

- Cables

100

- Sensor box

101

- Control unit or control electronics

102

- Output interface

104

- input interface

106

- Hanger

108

- Hangs

110

- Radio interface

112

- Valve

DCW

- cold process water

DHW

- hot 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

- Domestic water volume flow

Q _CH

- Heating medium volume flow

.DELTA.T

- Control difference

ωref

- Target speed

Claims (14)

1. A service water heating unit (2) which is provided for use in a heating installation,
   with at least one heat exchanger (6), which comprises a first flow path (10) for a heating medium and a second flow path (12) for service water to be heated, and with a first circulation pump (46) for the heating medium, said first circulation pump being connected to the first flow path (10) of the heat exchanger (6) and being fastened on the heat exchanger (6), wherein
   connections or fastening receivers are arranged on the heat exchanger (6) or on connection fittings connected to this, on which connections or rather fastening receivers a second circulation pump (76) which serves as a circulation pump for heated service water is fastened or can be fastened, characterised in that a connection fitting (30) which comprises a conduit connection (38) for a service water conduit and which is connected or connectable to a connection of the second circulation pump (76) is attached on the heat exchanger (6) at the entry of the second flow path (12).
2. A service water heating unit according to claim 1, characterised in that the first circulation pump (46) with a first connection is connected to the first flow path (10) of the heat exchanger (6), and with a second connection to a conduit connection (38) for the heating medium.
3. A service water heating unit according to claim 1 or claim 2, characterised in that the second circulation pump (76) is connected with a first connection to a conduit connection (88) for a circulation conduit (90) and with a second connection to a conduit connection for a service water conduit or to the second flow path (12) of the heat exchanger (6).
4. A service water heating unit according to any one of the preceding claims, characterised in that the heat exchanger (6) is a plate heat exchanger.
5. A service water heating unit according to claim 4, characterised in that the axis of rotation (X) of the first and/or second circulation pumps (46, 76) extend parallel to the plates of the heat exchanger (6).
6. A service water heating unit according to any one of the preceding claims, characterised in that the first (46) and second (76) circulation pump are arranged on two mutually opposed sides of the heat exchanger (6).
7. A service water heating unit according to claim 6, characterised in that the mutually opposed sides are formed by the outer plates (13) of a plate heat exchanger (6).
8. A service water heating unit according to any one of the preceding claims, characterised in that the conduit connection (38) of the connection fitting (30) is provided for connection to a cold water conduit.
9. A service water heating unit according any to one of the preceding claims, characterised in that a temperature sensor and/or flow sensor (96) is arranged in a flow path in the connection fitting (30).
10. A service water heating unit according to claim 9, characterised in that the connection fitting (30) comprises a flow channel with a first channel section to the conduit connection (38), and with a second channel section to the second circulation pump (76), said channel sections meeting at a junction (97), wherein the temperature and/or flow rate sensor (96) is situated in the first channel section at a distance from the junction (97).
11. A service water heating unit according to any one of the preceding claims, characterised in that a fastening element (50) is attached on the heat exchanger (6), to which at least one pipe conduit (80) connected to the second circulation pump (76) is fastened.
12. A service water heating unit according to any one of the preceding claims, characterised in that the second circulation pump (76) is designed in a removable manner, wherein a connection fitting (30) to the connection (40) of the second circulation pump (76) is provided and comprise a closable connection for the circulation pump (76).
13. A service water heating unit according to any one of the preceding claims, characterised by at least one sensor, in particular a temperature sensor and/or flow sensor (94, 96, 98), which is connected to a data detection module (100) comprising an output interface (102) designed for communication with an input interface (104) of a control unit (101) of at least one of the circulation pumps (46).
14. A service water heating unit according to any one of the preceding claims, characterised in that a holding device (106) is attached on the heat exchanger (6) which serves for fastening the service water heating unit (2) and is preferably formed as a retaining clip.

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