DE102021107817A1 - Heating system and method for operating a heating system - Google Patents

Abstract

The invention relates to a heating system (2), with a heat generator (4) which is set up to heat a heating fluid, a stratified storage tank (6) which is set up to store thermal energy of the heating fluid, the stratified storage tank (6) having a Container (8) with a plurality of vertically spaced hydraulic connections (10a-10d) for supplying and removing fluid, of which a first connection (10a) is arranged in an upper container area (15), in particular in an upper third of the container, and a second connection (10b) in a middle tank area (12) arranged under the upper tank area (15), in particular in a middle third of the tank, and a fluid line (14) which fluidly connects the heat generator (4) to the first connection (10a). According to the invention, a distributor arrangement (16) is proposed which has a valve (18) arranged in the fluid line (14) and a distributor line connected to the valve (18). g (20) which is connected to the second port (10b), the valve (18) having a first position (S1) and a second position (S2), in the first position (S1) heating fluid exclusively to the first connection (10a) and in the second position (S2) heating fluid is supplied exclusively to the second connection (10b), and by a control device (22) which is set up to switch the valve (18) as a function of a temperature difference (ΔT ) to the first position (S1) between a heating fluid temperature in the fluid line (TF) and a fluid temperature in the upper region of the stratified storage tank (To) if the temperature difference (ΔT) is less than a temperature threshold value (Ts), and otherwise bring the valve (18) to the second position (S2).

Description

The invention relates to a heating system with a heat generator which is set up to heat a heating fluid, a stratified storage tank which is set up to store thermal energy in the heating fluid, the stratified storage tank being a container with a plurality of vertically spaced hydraulic connections for supplying and discharging fluid, wherein a first connection is arranged in an upper container area, in particular in an upper third of the container, and a second connection is arranged in a middle container area arranged below the upper container area, in particular in a middle third of the container, and a fluid line which fluidly connects the heat generator to the first connection connects.

Such heating systems are known from the prior art. When using regenerative energy sources, such as heat pumps, for generating heat, it has proven useful not to connect the heat generator directly to an energy consumer, but to use a storage device between the heat generator and the energy consumer. Such a memory can be designed as a stratified memory.

Such a layered storage tank is a container filled with a fluid, in which layers of different temperatures are formed. Ideally, the layer temperature decreases from top to bottom. For this reason, heating fluid heated by a heat generator is fed to such stratified storage tanks in an upper container area, in which the fluid stored in the storage tank has the highest temperature. Fluid for heating applications is also taken from the reservoir in that upper area.

Disadvantages arise with such a configuration, in particular when using heat pumps as heat generators. After being put into operation, such heat pumps require a certain amount of time to heat the heating fluid to the desired temperature. The consequence of this is that after the start of such a heat pump, significantly cooler, not yet fully heated heating fluid is supplied to the stratified storage tank in an upper region in which fluid is present at a high temperature. This can severely disrupt the thermal stratification of the stratified storage tank. In addition, the heat consumers connected to the stratified storage tank are at least temporarily supplied with fluid that does not have the desired constant heating temperature. This can result in undesirable tap water temperature fluctuations for the consumer.

It is therefore known from the prior art to use additional heating elements between the stratified storage tank and the heat consumer. However, such heaters require additional power and add complexity to the installation, which is undesirable.

Against this background, the invention was based on the object of further developing a heating system of the type described at the outset in such a way that the disadvantages found in the prior art are eliminated as far as possible. In particular, a heating system was to be specified that compensates for temperature fluctuations in the heating fluid without requiring additional heating in the after-run of the stratified storage tank.

According to the invention, the object is achieved in a heating system of the type mentioned at the outset by a distributor arrangement which has a valve arranged in the fluid line and a distributor line which is connected to the valve and is connected to the second connection, the valve having a first position and a second position , wherein in the first position heating fluid is supplied to the first connection and in the second position the fluid is supplied to the second connection, and by a control device which is set up to switch the valve as a function of a temperature difference between a heating fluid temperature in the fluid line and a fluid temperature in the upper region of the stratified accumulator to the first position if the temperature difference is less than a temperature threshold and to position the valve to the second position otherwise.

The invention makes use of the finding that heating fluid is only fed through the distributor arrangement to the upper container area, which has a higher temperature, if the temperature of the heating fluid has a temperature difference from this temperature that is less than a temperature threshold value. If, for example, after the start of a heat generator designed as a heat pump, the heating fluid temperature is initially significantly lower than the fluid temperature in the upper container area, the valve switches to the second position. As a result, the heating fluid is fed to the stratified tank via the second connection in the middle of the tank. In this area, the fluid temperature in the container is typically lower, but at least there is no cooling of the heating fluid in the upper container area, which ultimately avoids temperature fluctuations at the outlets of the stratified storage tank. In this way it is possible to dispense with additional heating elements between the outlet of the stratified storage tank and a heat consumer. Of the This reduces the total energy requirement of the system.

According to a preferred embodiment, the valve is designed as a 2/3/2 mixer. The valve preferably has a servomotor which is set up to switch the valve between the first position and the second position. According to a preferred embodiment, the servomotor switches the valve to the second position when no electrical energy is supplied to the servomotor. According to an alternative embodiment, the controller is set up to switch the valve to the first position when a specified temperature is reached and to switch the valve to the second position when the temperature falls below the specified temperature. Preferably the set temperature is 46°C to 54°C, more preferably 50°C. According to a preferred embodiment, the control device has a 2-point controller. According to a preferred embodiment, the heating system has a temperature sensor which is arranged in the fluid line in front of the valve and is set up to sense the temperature of the heating fluid in the fluid line. In this way, a continuous monitoring of the heating fluid temperature is made possible, whereby temperature fluctuations that arise, for example, after the start of a heat generator can be detected.

The invention is further developed in that a temperature sensor is arranged in the upper container area, which is set up to sense the fluid temperature in the upper area of the stratified storage tank. This makes it possible to determine the thermal stratification of the stratified storage tank in the area of the temperature sensor.

According to a preferred development, the temperature threshold is 2.5°K to 7.5°K, in particular 5°K. In other words, it is proposed to only supply the heating fluid to the upper container area if the heating fluid temperature deviates by a maximum of the temperature threshold value, i.e. 2.5 °K to 7.5 °K, in particular 5 °K, and otherwise the heating fluid feed lower layer of the stratified memory via the second connection. In this case, the temporarily cooler heating fluid supplied does not lead to temperature fluctuations at the outlets of the stratified storage tank.

According to a preferred development, the valve has at least one further position, and the distributor arrangement has at least one further distributor line which is connected to the valve and which is connected in a fluid-conducting manner to at least one further connection of the layered accumulator. The at least one further connection is preferably arranged at a vertical distance from the first connection and the second connection. The control device is preferably set up to bring the valve into at least one further position when the temperature difference exceeds a second temperature threshold value. In this way, not only two areas can be provided in the stratified storage tank, into which heating fluid is introduced depending on the temperature, but also, for example, 3 or more areas can be provided, each area being assigned to a connection of the stratified storage tank. In this way, the thermal stratification of the stratified storage tank can be further optimized.

According to a preferred embodiment, the stratified storage tank has a horizontally aligned separating plate, which in particular separates the middle area of the stratified storage tank from the upper area. Such a separating plate has proven to be advantageous for improving the stability of the thermal stratification within the stratified storage tank.

The heat generator is preferably designed as a heat pump, in particular as a monovalently operated air/heat pump.

According to a preferred embodiment, the heating system has a heat consumer, which is fluidly connected to the stratified storage tank via a connection in the upper container area, in particular in the upper third of the container. The heat consumer is preferably designed as a home station for decentralized heating of drinking water.

The invention is further developed in that the distributor arrangement is arranged outside of the stratified store. Such an arrangement outside of the layered store, in particular outside of a housing of the layered store, allows the use of commercially available layered store without the need to structurally change the layered store itself.

The invention has been described above with reference to a heating system. In a further aspect, the invention relates to a method for operating a heating system, in particular a heating system according to one of the above exemplary embodiments, with a heat generator which is set up to heat a heating fluid, a stratified storage tank which is set up to store thermal energy of the heating fluid, wherein the stratified storage tank has a container with a plurality of vertically spaced hydraulic connections for supplying and removing fluid, with a first connection in an upper container area, in particular in an upper third of the container and a second connection in a middle container area arranged below the upper container area, in particular in a middle third of the container, and a fluid line which fluidly connects the heat generator to the first connection, and a distributor arrangement which has a valve arranged in the fluid line and a valve with the manifold connected to the valve and connected to the second port, the valve having a first position and a second position, in the first position the fluid is supplied to the first port and in the second position the fluid is supplied to the second port.

The invention solves the problem described at the outset in relation to the method with the steps: Switching the valve to the first position depending on a temperature difference between a heating fluid temperature in the fluid line and a fluid line in the upper region of the stratified storage tank when the temperature difference is less than a temperature threshold, otherwise switching the valve to the second position. According to a preferred embodiment, the temperature threshold is 2.5°K to 7.5°K, in particular 5°K.

The method makes use of the same advantages and preferred embodiments as the heating system according to the invention and vice versa. In this regard, reference is made to the above statements and their content is included here.

Further features and advantages of the invention result from the following description, in which exemplary embodiments are explained in detail with the aid of schematic drawings.

• - 1 bis 3 ein erstes Ausführungsbeispiel eines erfindungsgemäßen Heizungssystems in unterschiedlichen Betriebszuständen;
• - 4 ein alternatives Ausführungsbeispiel eines erfindungsgemäßen Heizungssystems.

Show in detail:

• - 1 until 3 a first embodiment of a heating system according to the invention in different operating states;
• - 4 an alternative embodiment of a heating system according to the invention.

1 shows a heating system 2 . The heating system 2 has a heat generator 4 . The heat generator 4 is set up to heat a heating fluid. The heating system 2 also has a stratified storage tank 6 . The stratified store 6 is set up to store thermal energy of the heating fluid. The stratified store 6 has a container 8 . The container 8 has a plurality of hydraulic connections 10a-10d spaced vertically from one another.

A first port 10a is arranged in an upper tank portion 15 . The upper container area 15 corresponds in particular to an upper third of the container. A second port 10b is arranged in a middle tank section 12 located below the upper tank section 15 . The middle container area 12 corresponds in particular to a middle third of the container. The heating system 2 also has a fluid line 14 . The fluid line 14 connects the heat generator 4 in a fluid-conducting manner to the first connection 10a.

The heating system 2 also has a distributor arrangement 16 . The distributor arrangement 16 has a valve 18 arranged in the fluid line 14 and a distributor line 20 connected to the valve 18 . The distribution line 20 is connected to the second port 10b. The valve 18 has a first position S1 and a second position S2. In the 1 and 2 the valve 18 is in the second position S2. In 3 the valve 18 is in the first position S1.

When the valve 18 is in the first position S1, heating fluid is supplied to the first port 10a. When the valve is in the second position S2, heating fluid is supplied to the second port 10b. The distributor arrangement 16 also has a control device 22 . The control device 22 is set up to bring the valve 18 into the first position S1 as a function of a temperature difference ΔT between a heating fluid temperature T _F in the fluid line 14 and a fluid temperature To in the upper region 15 of the stratified storage tank 6 when the temperature difference ΔT is smaller is as a temperature threshold T _s . The control device 22 is also set up to otherwise bring the valve 18 into the second position S2. The heating system 2 also has a temperature sensor 24 . The temperature sensor 24 is arranged in the fluid line 14 in front of the valve 18 . The temperature sensor 24 is set up to sense the heating fluid temperature T _F in the fluid line 14 . A further temperature sensor 26 is arranged in the upper interior area 15 of the container. The temperature sensor 26 is set up to sense the fluid temperature To in the upper region 15 of the stratified store 6 .

The stratified store also has a horizontally aligned partition plate 28 . The horizontally aligned separating plate 28 is arranged in the stratified store 6 in such a way that it separates the central area 12 from the upper area 15 . The heat generator 4 is designed as a heat pump 30 in the present case. The heat pump 30 is preferably a monovalently operated air/water heat pump 30.

In the in the 1 until 3 shown embodiment, the heat pump 30 via a Heat generator flow 40 fluidly connected to a switching valve 38. The fluid line 14 in turn connects to the switching valve 38 . A hydraulic connection 10d in the lower area of the container 6 is connected to a return 42, which leads to the heat generator 4. In this way, cooler fluid is supplied to the heat generator 4 from a lower region of the container 8 . The heat generator 4 is also fluidly connected via a storage inlet 50 and a storage return 52 to a storage 48 . The memory 48 is used to store thermal energy for heating applications. The reservoir 48 is in turn connected in a fluid-conducting manner via an apartment heating inlet 54 and an apartment heating return 56 to apartment underfloor heating systems 62 . A pump 60 is used to transport the heating fluid in the direction of the apartment underfloor heating 62. A heat consumer 32, which is presently designed as an apartment station 36 for decentralized heating of drinking water, is connected to the stratified storage tank 6. The heat consumer 32 is fluidly connected to the stratified storage tank 6 via a connection 34 in the upper container area 15 . A pump 60 supports the conveyance of the heating fluid in the direction of the heat consumer 32. The distributor device 16 is arranged outside of the stratified storage tank 6.

In addition, the stratified storage tank 6 has baffle plates 58 which are used to bring fluid into and out of the container 8 and out of the container 8 in a directed manner.

4 shows an alternative embodiment of a heating system 2, which in 4 is shown only in sections and in relation to the components that are not shown that heating system 2 of 1 until 3 is equivalent to.

At the in 4 The distributor arrangement 16 shown, the valve 18 has a total of three outlets, the valve 18 thus being able to be brought into a further valve position S _n . In this valve position _Sn , a further connection 10c is connected to the heat generator 4 in a fluid-conducting manner via a distributor line 20'. This can be the case, for example, when the 1 until 3 known temperature difference ΔT exceeds a second temperature threshold. Due to the additional valve position S _n and the resulting possibility of additionally supplying fluid to the stratified storage tank 6 via the further connection 10c, thermal stratification in the stratified storage tank 6 can be further optimized.

Below is the operation of the heating system 2 based on the 1 until 3 exemplified operating parameters explained. In 1 an operating state is shown in which the heat generator 4, which is presently designed as a heat pump 30, has just started operating. In this operating state, the heat generator 4 heats the heating fluid to 30°, for example. The heating fluid reaches the valve 18 and is supplied to the second connection 10b, which is lower than the first connection 10a, due to the temperature difference ΔT to the fluid temperature in the upper region of the stratified storage tank To. In this way, the thermal stratification in the upper container area 15 is not disturbed, ie in this area there is still a higher temperature of, for example, 52°. If, as is known from the prior art, the heating fluid heated to 30° were fed to the first connection 10a, the temperature stratification inside the container 8 would be disturbed and a temperature decrease would also occur at the connection 34, which would then move in the direction of the heat consumers 32 would be forwarded in an undesired manner. The configuration and control suggested here prevents this. In the in the 2 shown state, the heating fluid has heated to 45 °. Since this heating fluid still has a lower temperature than the fluid in the upper container area 15, the fluid is fed to the second connection 10b, with the thermal stratification within the stratified storage tank 6 being maintained again.

In the in the 3 shown state, the heating fluid has now heated to the desired temperature of 58 °. The valve 18 now switches to the first position and supplies the fluid to the first connection 10a. Layer memory 6 can now be loaded as desired.

Reference List

2

heating system

4

heat generator

6

stratified storage

8th

container

10a-d

hydraulic connections

10a

first connection

10b

second connection

12

middle tank area

14

fluid line

15

upper tank area

16

distribution arrangement

18

Valve

20, 20'

distribution line

22

control device

24

Fluid line temperature sensor

26

Vessel interior temperature sensor

28

partition plate

30

heat pump

32

heat consumers

34

Connection in the upper tank area

36

Apartment station for decentralized drinking water heating

38

switching valve

40

Heat generator flow

42

Return to the heat generator

44

home station feed

46

home station return

48

Storage

50

storage inflow

52

memory rewind

54

Apartment heating inlet

56

Residential heating return

58

baffle

60

pump

62

Apartment underfloor heating

S1

first valve position

S2

second valve position

sn

further valve position

ΔT

temperature difference

tf

Heating fluid temperature in the fluid line

TO

Fluid temperature in the upper area of the stratified storage tank

TS

temperature threshold

TS2

Another temperature threshold

Claims (14)

Heating system (2), with - a heat generator (4), which is set up to heat a heating fluid, - a stratified storage tank (6), which is set up to store thermal energy of the heating fluid, the stratified storage tank (6) having a container ( 8) having a plurality of vertically spaced hydraulic connections (10a-10d) for supplying and removing fluid, a first connection (10a) being arranged in an upper container area (15), in particular in an upper third of the container, and a second connection ( 10b) in a middle tank area (12) arranged under the upper tank area (15), in particular in a middle third of the tank, and - a fluid line (14) which fluidly connects the heat generator (4) to the first connection (10a), characterized by a distributor arrangement (16) which has a valve (18) arranged in the fluid line (14) and a distributor line (20) connected to the valve (18) and connected to the second Connection (10b) is connected, the valve (18) having a first position (S1) and a second position (S2), wherein in the first position (S1) heating fluid is supplied to the first connection (10a) and in the second position (S2) heating fluid is supplied to the second connection (10b), and by a control device (22) which is set up to switch the valve (18) as a function of a temperature difference (ΔT) between a heating fluid temperature in the fluid line (T _F ) and a fluid temperature in the upper region of the stratified accumulator (To) to the first position (S1) if the temperature difference (ΔT) is smaller than a temperature threshold value (Ts), and the valve (18) to the second position otherwise (S2) to bring. The heating system (2) after claim 1 , characterized by a temperature sensor (24) which is arranged in front of the valve (18) in the fluid line (14) and is set up to sense the heating fluid temperature (T _F ) in the fluid line (14). The heating system (2) according to one of the preceding claims, characterized by a temperature sensor (26) arranged in the upper container interior (15), which is set up to sense the fluid temperature (To) in the upper region (15) of the stratified storage tank (6). . The heating system (2) after claim 3 , wherein the temperature threshold (Ts) is 2.5°K to 7.5°K, in particular 5°K. The heating system (2) according to any one of the preceding claims, characterized in that the valve (18) has at least one further position (S _n ), and the distributor arrangement (16) has at least one further distributor line (20') connected to the valve (18). ) which is fluidly connected to at least one further connection (10c) of the layered accumulator (6). The heating system (2) after claim 4 , wherein the at least one further connection (10c) is arranged vertically spaced from the first connection (10a) and the second connection (10b). The heating system (2) after claim 4 , The control device (22) being set up to bring the valve (18) into at least one further position (S _n ) when the temperature difference (ΔT) exceeds a second temperature threshold value (T _S2 ). The heating system (2) according to any one of the preceding claims, wherein the stratified storage tank (6) has a horizontally aligned separating plate (28) which in particular separates the middle region (12) of the stratified storage tank (6) from the upper region (15). The heating system (2) according to one of the preceding claims, characterized in that the heat generator (4) is designed as a heat pump (30), in particular as a monovalently operated air/water heat pump (30). The heating system (2) according to one of the preceding claims, characterized by a heat consumer (32) which is fluidly connected to the stratified storage tank (6) via a connection (34) in the upper container area (15), in particular in the upper third of the container. The heating system (2) after claim 8 , wherein the heat consumer (32) is designed as a home station (36) for decentralized heating of drinking water. The heating system (2) according to any one of the preceding claims, wherein the distributor arrangement (16) is arranged outside of the stratified storage tank (6). Method for operating a heating system (2), in particular a heating system (2) according to one of the preceding claims, with - a heat generator (4) which is set up to heat a heating fluid, - a stratified storage tank (6) which is set up for this purpose , to store thermal energy of the heating fluid, the stratified store (6) having a container (8) with a plurality of vertically spaced hydraulic connections (10a-10d) for supplying and discharging fluid, a first connection (10a) being in an upper container region ( 15), in particular in an upper third of the container, and a second connection (10b) in a middle container area (12) arranged under the upper container area (15), in particular in a middle third of the container, and - a fluid line (14) which The heat generator (4) is connected in a fluid-conducting manner to the first connection (10a), and - a distributor arrangement (16) which has a valve (18) arranged in the fluid line (14) and d having a distribution line (20) connected to the valve (18) which is connected to the second port (10b), the valve (18) having a first position (S1) and a second position (S2), wherein in the first position (S1) heating fluid is supplied to the first connection (10a) and in the second position (S2) heating fluid is supplied to the second connection (10b), the method comprising: - switching the valve (18) as a function of a temperature difference ( ΔT) between a heating fluid temperature in the fluid line (T _F ) and a fluid temperature in the upper region of the stratified storage tank (To) in the first position (S1) if the temperature difference (ΔT) is less than a temperature threshold value (Ts), - Otherwise, switch the valve (18) to the second position (S2). The procedure after Claim 13 , wherein the temperature threshold (Ts) is 2.5°K to 7.5°K, in particular 5°K.

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