Heating system, method for operating a heating system and computer program

Abstract

A heating system (1) is proposed, comprising a primary heat exchanger (3) for heat exchange with a heat generator (2). The primary heat exchanger (3) is connected to a heating circuit (4) via a flow (15) and a return (16). A three-way valve (11) is arranged in the return (16) of the heating circuit (4), dividing the heating circuit (4) into a first partial heating circuit (5) and a second partial heating circuit (6). The first partial heating circuit (5) comprises consumers (7) of the heating system (1), and the second partial heating circuit (6) comprises at least one storage heat exchanger (9) configured to transfer heat to at least one hot water storage tank (8). The invention enables the use of the heat stored in a hot water storage tank (8) for heating the heating system (1). Furthermore, a method for operating such a heating system (1) and a computer program are proposed.

Description

[0001] The invention relates to a heating system, a method for operating a heating system and a computer program.

[0002] Heating systems can be set up for combined use for heating and hot water provision. To meet the different heat requirements of heating and hot water provision, the modulation range of gas condensing boilers can be increased to a ratio of approximately 1:10, for example, a power range of 3 kilowatts [kW] to 30 kW. The power requirement of a boiler for hot water provision has increased in recent years, while the power requirement for heating operation has decreased. The reason for the decreasing power requirement in heating mode can, for example, be improved insulation of the buildings to be heated. The disadvantage, therefore, can be a heat requirement for heating operation in the range of 2 kW and thus below the minimum power of the boiler, which results in the boiler being switched on and off frequently. This can place a strain on the boiler.The increasing energy demand for hot water supply can be due to the hot water fittings used, for example, the use of a rainfall showerhead, which requires 25 liters per minute compared to 7 liters per minute for a conventional showerhead. Providing a hot water flow of 25 liters per minute requires a heater output of significantly more than 30 kW. To meet such hot water requirements, hot water storage tanks are used, which can meet such requirements at least temporarily.

[0003] A disadvantage of using hot water storage tanks is their heat loss, in the form of heat being released to the environment, such as the room in which the hot water storage tank is installed.

[0004] EP 3 015 786 A1 attempts to address these disadvantages by proposing a thermal energy storage system using a phase-change material (PCM). However, this technically complex solution cannot reduce the heat loss of the hot water storage system.

[0005] The object of the present invention is to at least partially alleviate the problems described with reference to the prior art and, in particular, to propose a heating system, a method for operating a heating system and a computer program which can improve the energy efficiency of a heating system compared to the prior art.

[0006] The invention should also not increase the complexity of a heating system and should be easy to implement.

[0007] These objects are achieved by the features of the independent patent claims. Further advantageous embodiments of the solution proposed here are specified in the independent patent claims. It is pointed out that the features listed in the dependent patent claims can be combined with one another in any technologically expedient manner and define further embodiments of the invention. Furthermore, the features specified in the patent claims are further specified and explained in the description, with further preferred embodiments of the invention being presented.

[0008] A heating system contributes to this, comprising at least one primary heat exchanger for heat exchange with a heat generator, wherein the primary heat exchanger is connected to a heating circuit via a flow and a return. A three-way valve is arranged in the return or the flow, dividing the heating circuit into a first partial heating circuit and a second partial heating circuit. The first partial heating circuit comprises consumers of the heating system, and the second partial heating circuit comprises at least one storage heat exchanger configured to transfer heat to at least one hot water tank.

[0009] The heat generator can be a heating device, for example, one designed to burn a fuel such as oil or gas. The combustion gas can be a fossil gas such as natural gas or even hydrogen, possibly produced from sustainable energy sources. In particular, the heat generator can be designed as a gas condensing boiler, which enables a modulation ratio—the ratio of the lowest to the highest possible heat output—of 1:10 or more. Condensing technology enables the utilization of the condensation heat of the resulting water vapor in addition to the waste heat from combustion by cooling the exhaust gas stream below a condensation temperature.

[0010] A gas heater as a heat generator can draw in a mass flow of combustion air via a conveying device, to which a mass flow of fuel gas corresponding to a predetermined combustion air ratio (also known as lambda or air ratio) is added via a gas control device, for example, a gas valve. The resulting combustion mixture of combustion air and fuel gas can be fed via a mixture duct to a burner located in a combustion chamber, where it is combusted. The combustion products can be discharged to the outside via an exhaust pipe of the heater and a downstream exhaust system.

[0011] Furthermore, a primary heat exchanger is provided for heat exchange, connected to a flow and a return of the heating circuit. The primary heat exchanger can comprise several heat exchanger parts or heat exchanger compartments, for example, a first part / section of the primary heat exchanger configured, for example, to absorb the combustion heat, and a second part of the primary heat exchanger configured, for example, to absorb the condensation heat of the exhaust gas stream.

[0012] The heat generator can also be a heat pump, a (wall-mounted) electrically operated heater or an instantaneous water heater.

[0013] A three-way valve can be arranged in the flow or return of the heating circuit, and a branch can be arranged accordingly in the flow or return of the heating circuit, which divides the heating circuit into a first partial heating circuit and a second partial heating circuit. For the sake of clarity, the three-way valve can be arranged in the flow and the branch in the return, or vice versa. In this respect, the first partial heating circuit and the second partial heating circuit can be understood as parallel-running or parallel-flowing partial heating circuits (or parallel sections of the heating circuit), into which a mass flow of heat transfer medium flowing through the primary heat exchanger is distributed according to a mixing position or predefined setting of the three-way valve. The first partial heating circuit can (exclusively) integrate one or more consumers, such as radiators or underfloor heating systems.

[0014] A second partial heating circuit comprises at least one hot water storage tank, which stores, in particular, hot water for use as drinking or domestic water. The at least one hot water storage tank has at least one storage heat exchanger for heat exchange with the second partial heating circuit, which can transfer heat from the heat transfer medium of the second partial heating circuit to the domestic water contained in the hot water storage tank and vice versa. For this purpose, the hot water storage tank has a cold water inlet, which can be connected to a water supply, such as a mains supply or a well, and usually opens into a geodetically lower area of ​​the hot water storage tank. A withdrawal connection, which is connected to one or more taps, such as showers or faucets, can be arranged in a geodetically upper area of ​​the storage tank due to the resulting temperature stratification.The storage heat exchanger can, for example, be designed as a spiral-shaped pipe within the hot water tank. Several hot water tanks can be connected in parallel or (preferably) in series.

[0015] The returns from the first partial heating circuit and the second partial heating circuit can be combined in the return of the heating circuit (primary heat exchanger) by means of the three-way valve or in the three-way valve. Thus, the three-way valve can ensure that a mass flow of heat transfer medium is supplied to the primary heat exchanger, which is mixed from the return of the first partial heating circuit and the return of the second partial heating circuit according to a mixing position of the three-way valve. The second partial heating circuit serves in particular for heat exchange with the hot water storage tank and can therefore exclusively comprise one or more storage heat exchangers for one or more hot water storage tanks. This exclusion is to be understood with regard to further heat exchangers or devices for heat extraction and / or supply.

[0016] The three-way valve can be a three-way valve suitable for heating circuits. It can include an actuator, such as a stepper motor, that can adjust the mixing position of the three-way valve. The mixing position can be adjusted using an electronic control unit, such as a control and regulation unit of the heating system.

[0017] In addition, the heating system can include multiple temperature sensors. These can be located, in particular, in the flow and return lines of the first partial heating circuit and the second partial heating circuit and / or in the hot water tank. In this case, multiple temperature sensors can be located at different geodetic heights within the hot water tank, enabling the detection and / or incorporation of a developing temperature stratification into the determination of the thermal energy stored in the hot water tank.

[0018] A circulation pump can be arranged in the heating circuit at a position that allows heat transfer medium to be pumped through both the first partial heating circuit and the second partial heating circuit. In particular, the circulation pump can be arranged between the three-way valve and the primary heat exchanger and / or in the flow of the heating circuit between the junction of the first partial heating circuit and the second partial heating circuit and the primary heat exchanger. For the sake of completeness, it should be noted that multiple circulation pumps can also be provided. The circulation pump can also be arranged at a different position in the flow or return, in particular in the undivided area, i.e., the area from the heat generator to the three-way valve or the junction.

[0019] The heat transfer medium circulating in the heating circuit (i.e. in the first partial heating circuit and the second partial heating circuit) can be, for example, heating water.

[0020] According to a further aspect, a method for operating a heating system is proposed. In this case, a target flow temperature of the heating circuit is set by a mixing position of the three-way valve when heating is requested and the heat generator is switched off. The heat transfer medium is thereby mixed by the three-way valve to the target flow temperature and is supplied to the first partial heating circuit and second partial heating circuit, and thus to the consumers and the storage heat exchanger, in proportion to the mixing position of the three-way valve. The invention thus enables the heat stored in the hot water tank to be used for heating. The target flow temperature can be or have been determined according to a heating curve. The mixing position of the three-way valve to be set for this purpose can be specified or calculated based on a temperature of the hot water tank and / or a temperature of the return flow of the first partial heating circuit.Alternatively, a mixed temperature can be controlled using the flow or return temperature sensor of the heater. Last but not least, an expected mixed temperature can be calculated based on a volume flow analysis by assigning a position of the three-way valve to a distribution of the volume flows and a storage temperature.

[0021] Furthermore, a control system or control loop can be provided to regulate the desired flow temperature based on the mixing position of the three-way valve. This can use the options mentioned above to determine the mixing temperature, for example, controlling a mixing temperature (detected by a flow or return temperature sensor of the heater) with the mixing position of the three-way valve as the actuator. Alternatively, the temperatures in the returns of the first partial heating circuit and / or the second partial heating circuit can be input variables for the control system, which specifies the mixing position of the three-way valve as the manipulated variable and the desired flow temperature as the setpoint. For this purpose, the resulting mixing temperature (downstream of the three-way valve in the return or in the flow of the heating circuit) can also be recorded and taken into account if necessary.

[0022] The method can be carried out, in particular, by means of a control unit of the heating system or the heat generator. For this purpose, the control unit can be electrically connected to the three-way valve, the heat generator, the circulation pump, and the temperature sensors.

[0023] The method proposed here, in conjunction with a heating system proposed here, thus enables the thermal energy stored in the hot water tank to be used by the consumers of the first partial heating circuit. The heat transfer medium mass flow supplied to the primary heat exchanger, at the target flow temperature set by the three-way valve, is fed via the primary heat exchanger to the flow of the first heating circuit and there distributed between the first partial heating circuit and the second partial heating circuit according to the set mixing position of the three-way valve. When the heat generator is switched off, i.e. without heating the heat transfer medium in the primary heat exchanger, a target flow temperature can be set in the return or flow using the three-way valve. This is possible because the flow and return temperatures are the same when the heat generator is switched off.

[0024] If a temperature in the hot water tank is detected below a limit temperature, charging of the hot water tank can be initiated. For this purpose, the heat generator can be started up and heat transfer medium heated by the primary heat generator can be directed to the storage heat exchanger, where heat energy is transferred into the hot water tank. The three-way valve can then assume a mixing position, which supplies the entire mass flow of heat transfer medium heated by the primary heat exchanger to the hot water tank. Alternatively, the three-way valve can also supply a portion of the mass flow of heat transfer medium heated by the primary heat exchanger to the first heating circuit to maintain heating operation. The limit temperature can be set by the user according to comfort requirements. The limit temperature can also be adjusted according to the time of day and / or predefined usage scenarios.

[0025] According to one embodiment of the method, the threshold temperature can be determined based on recorded user behavior. This user behavior can, in particular, relate to hot water usage or withdrawal. In particular, user behavior, especially hot water withdrawals, can also be recorded and analyzed using artificial intelligence. During periods in which no or very low hot water withdrawals occur, the threshold temperature for charging the hot water storage tank can be lowered, thus reducing the heat loss from the hot water storage tank.

[0026] This allows two operating states of the heating system to be detected. A first operating state ensures heating operation and the possibility of (simultaneous) hot water withdrawal when the heat generator is switched off. In a second operating state, the heat generator is in operation and can supply heat energy to the hot water storage tank for charging, as well as to consumers in the second partial heating circuit for heating. Hot water withdrawal is also possible in the second operating state.

[0027] According to a further aspect, a computer program is also proposed which is designed to (at least partially) carry out a method presented here. In other words, this relates in particular to a computer program (product) comprising commands which, when the program is executed by the heater, the heating system proposed here, or a control and regulating device of the heater or the heating system, cause the heating system to carry out a method proposed here. For this purpose, the heating system can have at least one or more temperature sensors to which a computer carrying out the method can be electrically connected. In addition, the computer carrying out the method can be electrically connected to the electrically controllable actuator of the three-way valve.In addition, parameters necessary for carrying out the process, such as a heating curve or a limit temperature, can be stored in the memory of the computer carrying out the process.

[0028] The explanations of the heating system can also be used to further characterize the process and / or the computer program, and vice versa.

[0029] As a precaution, it should be noted that the numerals used here ("first", "second", ...) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and therefore do not necessarily specify any interdependence and / or sequence of these objects, quantities, or processes. Should a dependence and / or sequence be required, this is explicitly stated here or will be obvious to the person skilled in the art upon studying the specifically described embodiment. To the extent that a component can occur multiple times ("at least one"), the description of one of these components may apply equally to all or part of the majority of these components, but this is not mandatory.

[0030] Thus, a heating system, a method for operating a heating system, and a computer program are provided here, which at least partially solve the problems described with reference to the prior art. In particular, the heating system and the method at least contribute to increasing the energy efficiency of the heating system by meeting the heat requirements of the heating operation by utilizing the thermal energy available in a hot water tank. As a result, the temperature in the hot water tank and thus the temperature difference to the ambient temperature can drop, and with it the heat loss can be reduced. A further associated positive effect is a reduction in the frequency with which the heater is switched on and off, which can reduce wear and tear and increase service life.

[0031] The invention also makes it possible to reduce the requirements for the modulation range of a heating device, as low heat requirements of the heating system can be met by utilizing the thermal energy from the hot water tank. For example, using the hot water tank for heating can meet heat requirements of less than 5 kW, thus requiring the heat generator to be commissioned only for heat requirements of greater than 5 kW. This could also be understood as increasing the modulation range of the overall system. In this respect, the invention can also be used to configure older heating devices with a lower modulation ratio so that they operate in a heating system with a wide power spread.

[0032] The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments cited. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description. In particular, it should be noted that the figures and, in particular, the proportions shown are only schematic. It shows: Fig. 1: a heating system proposed here.

[0033] Fig. 1shows, by way of example and schematically, a heating system 1 proposed here. This comprises a heat generator 2 and a primary heat exchanger 3 for transferring heat from the heat generator 2 to a heating circuit 4. The heating circuit 4 has a flow 15 and a return 16. A three-way valve 11 can be arranged in the return 16, which divides the heating circuit 4 into a first partial circuit 5 with a return 22 and a second partial circuit 6 with a return 21. The flow 15 of the heating circuit 4 can be divided at a branch 18 into a flow 20 of the first partial heating circuit 5 and a flow 19 of the second partial heating circuit 6. It is noted that, alternatively, the three-way valve 11 can be arranged in the flow 15 and the branch 18 in the return 16.

[0034] Consumers 7, for example, underfloor heating or radiators, can be integrated into the first sub-circuit 5. The second sub-circuit 6 can contain a hot water storage tank 8 for receiving and discharging heated drinking or service water, and a storage heat exchanger 9 for exchanging heat between the hot water storage tank 8 and the heat transfer medium circulating in the second sub-circuit 6. The heat transfer medium is circulated in the heating circuit 4 or the first and second sub-circuits 5, 6 by means of a circulation pump 10 in a circulation direction 17.

[0035] A first temperature sensor 13 can be arranged in the return line 22 of the first partial heating circuit 5, and a second temperature sensor 14 can be arranged in the return line 21 of the second partial heating circuit 6 to detect the temperature of the heat transfer medium. A control and regulating device 12 of the heating system 1 can be electrically connected to the three-way valve 11, the circulation pump 10, and the first and second temperature sensors 13, 14. It should be noted that additional temperature sensors can be used, in particular a temperature sensor arranged downstream of the three-way valve 11 with respect to the circulation direction 17 to detect the temperature set by the mixing position of the three-way valve 11. A flow or return temperature sensor of the heater / heating system 1 (which is usually present anyway) can also be used for this purpose, making the first and second temperature sensors 13, 14 unnecessary.Alternatively, this temperature can also be adjusted by a control with the mixing position of the three-way valve as the actuator.

[0036] According to a method proposed here, a target flow temperature, which was determined, for example, based on the heat requirement and the heating curve, can be set based on a mixing position of the three-way valve 11. Based on the measurement signals of the first temperature sensor 13 in the return line 22 of the first partial heating circuit 5 and the second temperature sensor 14 in the return line 21 of the second partial heating circuit 6, a mixing position of the three-way valve 11 can be determined in order to set the target flow temperature. By controlling the three-way valve 11, the three-way valve 11 can be set to the specific mixing position. Heat transfer medium with the target flow temperature is then supplied to the first and second heating circuits in accordance with the determined and set mixing position of the three-way valve 11. The heat transfer medium in the first partial heating circuit 5 is cooled by the consumers, and the heat transfer medium in the second partial heating circuit 6 is heated in the storage heat exchanger 9.

[0037] Alternatively, a target flow temperature can be specified. This can be continuously compared with the temperature of the return line 16 or the temperature of the flow line 15 (which are the same when heat generator 2 is switched off). If there is a deviation, the 3-way valve is adjusted to maintain the specified target flow temperature.

[0038] The hot water storage tank 8 can be charged by starting up the heat generator 2. Furthermore, the three-way valve 11 can be set to a mixing position, in which the mass flow from the primary heat generator 3 is almost entirely fed to the storage heat exchanger 9. For this purpose, the heat generator 2 can be operated at high or nominal power to enable rapid heating of the hot water storage tank 8. List of reference symbols

[0039] 1Heating system 2Heat generator 3Primary heat exchanger 4Heating circuit 5First partial heating circuit 6Second partial heating circuit 7Consumer 8Hot water tank 9Storage heat exchanger 10Circulation pump 11Three-way valve 12Regulating and control unit 13First temperature sensor 14Second temperature sensor 15Heating circuit flow 16Heating circuit return 17Circulation direction 18Branch 19Flow second partial heating circuit 20Flow first partial heating circuit 21Return second partial heating circuit 22Return first partial heating circuit

Claims

1. Heating system (1), comprising a primary heat exchanger (3) for heat exchange with a heat generator (2), wherein the primary heat exchanger (3) is connected to a heating circuit (4) via a flow line (15) and a return line (16), and a three-way valve (11) is arranged in the flow line (15) or return line (16) of the heating circuit (4), which three-way valve divides the heating circuit (4) into a first partial heating circuit (5) and a second partial heating circuit (6), wherein the first partial heating circuit (5) comprises consumers (7) of the heating system (1) and the second partial heating circuit (6) comprises at least one storage heat exchanger (9) designed to transfer heat to at least one hot water storage tank (8).

2. Heating system (1) according to claim 1, wherein the heat generator (2) is a gas condensing boiler.

3. Heating system (1) according to one of the preceding claims, wherein a circulation pump (10) is arranged in the flow (15) and / or return (16) of the heating circuit (4) between the three-way valve (11) and the primary heat exchanger (3) and / or between a branch (18) of the first partial heating circuit (5) and the second partial heating circuit (6) and the primary heat exchanger (3).

4. Heating system (1) according to one of the preceding claims, wherein the second partial heating circuit (6) is designed exclusively for heat exchange with a hot water storage tank (8).

5. Method for operating a heating system (1) according to one of the preceding claims, wherein, in the event of a heating request when the heat generator (2) is switched off, a desired flow temperature of the heating circuit (4) is set by a mixing position of the three-way valve (11).

6. Method according to claim 4, wherein when a temperature in the hot water tank (8) and / or in the return line (21) of the second partial heating circuit (6) is detected to be below a limit temperature, the three-way valve (11) is moved into a charging position in which, when the heat generator (2) is switched on, heated heat transfer medium in the primary heat exchanger (3) is supplied to the hot water tank (8).

7. The method according to claim 6, wherein the limit temperature is determined based on recorded user behavior.

8. Heating system (1) according to one of claims 1 to 4, comprising means for carrying out a method according to one of claims 5 to 7.

9. Computer program comprising instructions which cause a heating system (1) according to claim 8 to carry out a method according to one of claims 5 to 7.

10. Control and regulation device (12) of a heating system (1), arranged to carry out a method according to one of claims 5 to 7.

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