EP2413048A1 - Domestic water heating unit - Google Patents

Abstract

The unit has a control unit controlling warming of processing water and designed for detecting requirement of the processing water. The control unit evaluates an output signal of a temperature sensor (96) i.e. flow rate sensor. The sensor is arranged in proximity of a node point (97) and at a distance from the node point in a cold processing water (DCW). The control unit switches-on and switches off a circulation pump (46) in dependent upon requirement of the processing water. A circulation control is partially integrated in the control unit.

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 a heating system 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 by a heating medium in the manner of a water heater.

A domestic water heating unit represents a unit in which all the essential components for heating the service water are integrated and thus delivered as a preassembled unit and integrated or can be installed in the heating system.

To control the domestic water heating, it is necessary, a service water demand, d. H. to detect the opening of a tapping point for heated service water to then put the service water heating by means of the heating medium in operation, for example, to promote heating medium by means of a circulation pump through a heat exchanger.

In the event that a circulation is additionally provided for the service water in order to keep the service water in the service water pipes of a building heated even when not in use, it is however difficult to distinguish a service water requirement from the flow caused by the circulation.

In view of this problem, it is an object of the invention to provide a service water heating unit, which can reliably detect a service water request even when using a hot water circulation.

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

The hot water heating unit according to the invention is, as described above, a structural unit, which is intended for installation in a heating system, and in the heating system, the heating of the hot water takes over. In this case, the service water heating unit has at least one heat exchanger as a central component. In addition, the domestic water heating unit as an integrated unit, preferably all other necessary for the heating of the service water elements, such as required pumps, valves, fittings or connection fittings, sensors and / or a control device or control unit to control the hot water heating. Such a service water heating unit can be integrated as a preassembled unit in a heating system. The service water heating unit has required line connections to connect the service water heating unit with a heating system or the pipes in a building. These line connections are in particular an input and output for the heating medium, an input and output for the hot water to be heated and a circulation line for hot water circulation. In addition, preferably an electrical connection for the power supply and, where appropriate, provided interfaces for data communication with external equipment, such as a central system control and / or a heating control.

The heat exchanger is preferably designed as a plate heat exchanger. Such a plate heat exchanger can be made for a cost and on the other hand are designed to be inherently stable, so that it can form a supporting component of the service water heating unit to which further, preferably all other components are attached. Thus, external support structures for fastening the components of the service water heating unit can be dispensed with in the ideal case.

The at least one heat exchanger has a first flow path for a heating medium, which is optionally provided via connection fittings with line connections for connection to the heating circuit or a heat storage. In addition, a second flow path for the hot water to be heated is provided. The two flow paths in the interior of the heat exchanger are separated from each other, so that a heat transfer between the two is possible. In an input line to the second flow path, a node is provided, in which two flow channels open, namely on the one hand a cold water line and on the other a circulation line for heated hot water. Ie. cold water to be heated and circulated, already heated service water are fed into an input line to the second flow path of the heat exchanger.

In addition, the service water heating unit has a control unit, which is provided for controlling or regulating the hot water heating. The control unit controls in particular the heat supply via the heating medium, for example by controlling a circulation pump for supplying the heating medium. The control unit is designed to detect a service water request. Ie. the control unit can detect when hot tap water heated at a tapping point is removed to accordingly cause the supply of heating medium to heat the tap water via the heat exchanger.

According to the invention, the control unit is designed to evaluate the output signal of a temperature sensor, which is arranged in the vicinity of the junction, but spaced from it, in the cold water line. By means of such a temperature sensor, it is possible to detect the service water request. When cold service water flows through the cold water line, which is to be heated by the heat exchanger, a temperature sensor in the cold water line will detect the temperature of the cold supplied service water. However, since the temperature sensor is disposed in the vicinity of the node at which the circulation line opens, in the case that no heated service water is required and thus there is no flow in the cold water line, the water in the cold water line is already circulated from the already heated one Hot water, which flows through the junction, heated due to the proximity. This can be detected at the temperature sensor. Now, when hot water is requested, again enters a flow in the cold water line, so that cold water flows into it and there comes to a detectable by the temperature sensor temperature drop. It is thus possible to determine the service water requirement by means of a temperature sensor, so that a flow sensor can be dispensed with for this purpose. So it is easily possible even with circulation of the heated service water in the hot water lines to distinguish the circulation of an actual service water needs.

Preferably, the temperature sensor is arranged vertically above the node. This favors the heating in the absence of flow in the cold water line, as heated circulated hot water can rise in the cold water pipe.

The temperature sensor is also expediently arranged at a position in that of the cold water line at which an influence of the temperature in the circulation line on the temperature in the cold water line is given. Ie. the distance of the temperature sensor from the node must not be too large. The temperature sensor must be arranged so close to the junction that, at the location of the temperature sensor, heating of the stagnant water in the cold water line is still provided by the circulated, heated service water entering the junction.

The control unit is preferably designed such that it recognizes a service water request on the basis of a temperature change detected by the temperature sensor, in particular a temperature profile. Ie. the temperature is recorded over time and changes or the temperature profile over time are evaluated. Based on a characteristic temperature profile, in particular a temperature drop, the service water request can be detected by the control unit. As described above, the temperature sensor detects different temperatures, depending on whether there is a flow in the cold water line or the water is there and can be heated by the circulated service water. From these temperature changes, the control unit detects the hot water requirement, namely, when in the cold water line, a flow occurs, which leads to a reduction in the prevailing temperature there.

Particularly preferably, a circulating pump is provided which conveys the heating medium through the heat exchanger. In this circulation pump in particular, it is a variable speed circulating pump, so that it can vary the flow rate of the heating medium as needed, the speed is set by the control unit depending on the heat demand for heating the service water.

In addition, the control unit is preferably designed to turn on and off the circulation pump in response to a service water request. Ie. when the control unit detects the dhw demand, d. H. a flow in the cold water pipe through which service water is supplied, the control unit turns on the circulation pump to supply heating medium to the heat exchanger for heating the service water. The flow in the cold water line is, as described above, detected by means of the temperature sensor arranged there.

Particularly preferably, the control unit is at least partially integrated in the control electronics of the circulating pump, wherein the circulating pump is designed as a control electronics and an electric drive motor exhibiting Umwälzpumpenaggregat. The control electronics serve to control or regulate the drive motor. In particular, the drive motor preferably has a speed control, so that the control device can control or regulate the flow rate of the circulation pump via the rotational speed of the drive motor. If the control unit for controlling the DHW heating is integrated in the control electronics of the circulating pump unit, the installation and commissioning of the domestic water heating unit is simplified, since this eliminates the need to establish a connection between the control unit and circulating pump. Only one connection or communication between the circulating pump unit with the integrated control unit and the sensors has to be established.

In a particular embodiment, the temperature sensor is a combined temperature-pressure sensor and / or a temperature-flow sensor which, in addition to the temperature, detects an absolute and / or differential pressure or a flow in the cold-water line. The flow measurement can be carried out as a vortex measurement by means of an obstruction and a pressure sensor. The pressure or flow signal can be used for further control or control functions in the service water heating unit.

On the output side of the second flow path of the heat exchanger, d. H. the flow path for the service water, a temperature and / or flow sensor is further preferably arranged, whose output signals are detected by the control unit, wherein the control unit is configured such that it determines the need for heating medium for the domestic water heating on the basis of these output signals. In particular, the control unit can compare the detected starting temperature of the service water at the second flow path with a desired temperature. Falling below the setpoint temperature means that there is an increased heat requirement. On the basis of this information, the control unit can then cause an increased supply of heat via the heating medium, for example, by increasing the flow rate of the heating medium supplying circulating pump by increasing the speed thereof. The flow in the second flow path for the service water is a measure of the required heat demand. An increased flow means increased heat demand, so that the control unit can directly increase the supply of heating medium, in particular by increasing the speed of the heating medium supplying circulating pump.

Thus, the control unit preferably adjusts the flow rate of the circulation pump as a function of the detected requirement for heating medium. This is particularly cheap then possible if the control unit directly into the Control electronics of the circulation pump or the circulating pump unit is integrated.

More preferably, a temperature sensor for detecting the temperature of the heating medium supplied to the heat exchanger is arranged on the input side of the first flow path of the heat exchanger. This temperature represents a further parameter on the basis of which the control device can adjust the flow rate of heating medium by means of speed control or control of the circulating pump feeding the heating medium. A lower heating medium temperature requires a higher volume flow. Fluctuations in the heating medium temperature can occur, for example, when the heating medium is heated by a solar system or a heat storage is removed.

A circulation pump is preferably arranged in the circulation line, and a circulation control is provided, which is designed such that it switches on and off the circulation pump at least taking into account the detected temperature of the heating medium. This makes it possible to dispense with a too low temperature of the supplied heating medium to the circulation. Thus, the circulation pump can be switched off by the circulation control, when the temperature detected by the temperature sensor, which is arranged on the input side of the first flow path of the heat exchanger, falls below a predetermined limit value. This is particularly useful when the service water heating unit is used in conjunction with a heat storage, which is taken from the heating medium. If the temperature in the heat accumulator is too low, the circulation can be stopped by switching off the circulation pump to prevent further cooling of the heat accumulator. Again, this makes sense in particular in combination with solar systems, so that there circulation, for example, then can be exposed if too little sunlight is given to heat the heating medium.

The circulation control is further preferably at least partially integrated into the control unit for controlling the domestic water heating, particularly preferably it can be fully integrated in this, wherein the control unit itself may also be fully or partially integrated into the control electronics of Umwälzpumpenaggregates for conveying the heating medium. Alternatively, it would also be conceivable to integrate the circulation control and the control unit for controlling the DHW heating in each case completely or partially into the control electronics of the circulation pump. By integrating these control components in the control electronics of a circulating pump unit, the number of electronic components to be installed is reduced, which reduces material costs and installation costs. The circulation pump can communicate with the circulating pump for conveying the heating medium via a suitable interface, in particular wirelessly, for example by radio, so that the control electronics of the circulating pump for the heating medium can also control the circulation pump.

To simplify the integration of the sensors, a data acquisition module can be provided, with which the temperature sensor and / or the other sensors, such as the temperature sensor input side of the first flow path and pressure and flow sensors can be connected. For this purpose, the data acquisition module has suitable connections for the sensors, in particular connection plugs or terminals, to which the sensors can be connected by means of data lines. Alternatively, a wireless communication between the data acquisition module and the sensors via suitable interfaces, in particular radio interfaces conceivable. The data acquisition module has an output interface at which it detects a detected sensor signal or Sensor signals and / or derived data provides. The control unit in turn has an input interface for accepting signals or data from the output interface. Thus, the control unit can read signals or data from the output interface of the data acquisition module via its input interface, in order to control or regulate the DHW heating and, if appropriate, the circulation on the basis thereof. Such a data acquisition module has the advantage that the sensors do not have to be connected directly to the control unit. This is particularly advantageous when the control unit is integrated in a pump unit, since so can be dispensed with a large number of sensor connections in a relatively small space. Also, the sealing of the pump unit is not affected to the outside, since no connections for sensors would have to be provided. Instead, only an interface to the data acquisition module needs to be provided. Also, the removal and installation of the pump unit is simplified, since the connections of the sensors are not affected.

Particularly preferred are the output interface and the input interface for wireless communication, in particular by radio. In this way, no connections for connecting cables for communication between the control unit and the data acquisition module are required at all, so that, for example, if the control unit is integrated in a circulation pump, these need not have any other connections except the connection for a power cable. This improves the sealing of the control electronics of the pump unit and simplifies the assembly of the pump unit.

Fig. 1

eine Gesamtansicht einer an einem Wärmespeicher ange-ordneten Brauchwassererwärmungseinheit,

Fig. 2

eine perspektivische Gesamtansicht der Brauchwasserer-wärmungseinheit 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 Brauchwasserer-wärmungseinheit mit Brauchwasserzirkulationsmodul,

Fig.8

eine perspektivische Ansicht der Brauchwassererwärmungs-einheit 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 Brauchwasserer-wärmungseinheiten gemäß Fig. 14 und

Fig. 16

schematisch den Regelkreis zur Regelung der Brauchwasser-erwärmungseinheiten.

The invention will now be described by way of example with reference to the accompanying drawings. In these shows:

Fig. 1

an overall view of an attached to a heat storage hot water heating unit,

Fig. 2

an overall perspective view of the domestic 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,

Fig. 7

an exploded perspective view of the domestic 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 several domestic 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 is to be heated Hot water heated and discharged as heated hot water, for example, to supply taps in a house 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, 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, first of the already cooled is heated at the output 16 exiting 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 output 20 heated service water is not heated directly through the entering at 14 inlet hot medium in the last section of its flow path 12, 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 discharge of the service water is not in the range of the highest temperature the incoming heating medium is, 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 hot 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 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 opposite port opening 40 of the flow channel 32 is on the base member 28th when used in the first connection fitting 26, a first circulating pump 46 is arranged, which supplies 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 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 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 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 42 is connected to supply the cold service water. Through this line then enters the cold water in the inlet 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 facing away from the connection element 82 with the end opening 40 of the flow channel 32 in the second connection fitting 30 is connected, 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, 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 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 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 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 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. If this detects a flow in the flow path through the connection part 60, ie a hot water flow, this means that a hot water tapping point is open, so that cold service water flows through the connection opening 38 and a heat requirement for heating the service 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, since the sensor 98 also detects a flow, due to the circulation 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 successive service water requirements are shown, which in each case again lead to a drop in temperature and at the end of the request for heated service water to a temperature rise, since that in the line section in which the Temperature sensor 96 is arranged, located water 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 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 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 circulating pump 76 and possibly 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 the leading module M2 in step A a dhw request detects, first, this service water heating unit 2 is put into operation, ie the circulation pump 46 promotes heating medium to the associated heat exchanger 6. If now the Brauchwassererförderung is switched off from step B to C, this leading service water heating unit 2 is still heated 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 turned off and the control units 101 of the individual service water heating units 2 set each other again the star sequence. 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 first in operation is taken, preferably a service 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 star sequence, ie this is switched on only at maximum load and serves only to warm the circulating service 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 set temperature For example, it may be adjustable 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 T _ref , the actual temperature T _{DHW of} the heated service water DHW detected by the 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 _CH in the heat 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

ω _ref

- Target speed

Claims (16)

Domestic hot water heating unit (2) with
at least one heat exchanger (6) having a first flow path (10) for a heating medium and a second flow path (12) for hot water to be heated, wherein a cold water line (DCW) and a circulation line (90) for heated service water in a node (97 ) in an input line to the second flow path (12) of the heat exchanger (6) open,
and a control unit (101) for controlling the heating of service water, wherein the control unit (101) is designed to detect a service water request
characterized in that
the control unit (101) is designed to evaluate the output signal of a temperature sensor (96) which is arranged in the vicinity of the node (97) but spaced from it in the cold water line (DCW). Domestic water heating unit according to claim 1, characterized in that the temperature sensor (96) is arranged vertically above the node (97). Domestic water heating unit according to claim 1 or 2, characterized in that the temperature sensor (96) is arranged at a position in the cold water line (DCW), at which an influence of the temperature in the circulation line (90) given to the temperature in the cold water line (DCW) is. Domestic water heating unit according to one of the preceding claims, characterized in that the control unit (101) is designed such that it uses a dhw request one of the temperature sensor (96) detected temperature change, in particular a temperature profile recognizes. Domestic water heating unit according to one of the preceding claims, characterized by a circulating pump (46) which conveys the heating medium through the heat exchanger (6). Domestic water heating unit according to claim 5, characterized in that the control unit (101) is designed to switch on and off the circulation pump (46) in dependence on a service water requirement. Domestic water heating unit according to claim 5 or 6, characterized in that the control unit (101) is at least partially integrated in the control electronics of the circulation pump (46), wherein the circulation pump (46) is designed as a control electronics and an electric drive motor exhibiting Umwälzpumpenaggregat. Domestic hot water heating unit characterized in that the temperature sensor (96) is a combined temperature-pressure sensor, which detects an absolute and / or differential pressure in addition to the temperature. Domestic water heating unit, characterized in that on the output side of the second flow path (12) of the heat exchanger (6) a temperature and / or flow sensor (98) is arranged, whose output signals from the control unit (101) are detected, wherein the control unit (101) configured is that it determines the need for heating medium for domestic water heating based on these output signals. Domestic water heating unit according to claim 9, characterized in that the control unit (101) is designed such that it adjusts a flow rate of the circulation pump (46) in dependence of the detected demand for heating medium. Domestic water heating unit according to one of the preceding claims, characterized in that a temperature sensor (94) for detecting the temperature of the heating medium is arranged on the input side of the first flow path (10) of the heat exchanger (6). Service water heating unit according to claim 11, characterized by a circulating pump (76) arranged in the circulation line (90) and a circulation control which is designed such that it switches on and off the circulation pump (76) at least taking into account the detected temperature of the heating medium. Service water heating unit according to claim 12, characterized in that the circulation control is designed such that it switches off the circulation pump (76) when the temperature of the heating medium falls below a predetermined limit value. Domestic hot water heating unit according to claim 12 or 13, characterized in that the circulation control is at least partially integrated into the control unit (101) for controlling the hot water heating. Domestic water heating unit according to one of the preceding claims, characterized in that the temperature sensor (94, 96, 98) is connected to a data acquisition module (100) having an output interface (102) at which it provides a detected sensor signal and / or data derived therefrom, and the control unit (101) having an input interface (104) to accept signals or data from the output interface (102). Domestic hot water heating unit according to claim 15, characterized in that the output interface (102) and the input interface (104) are designed for wireless communication, in particular by radio.

Images