Method for operating a heating system, heating system and computer program

Abstract

A method for operating a heating system (1) is proposed.The heating system (1) has a heat generator circuit (13) with a first circulation pump (8) and a flow sensor (5), wherein the heat generator circuit (13) is hydraulically connected to a first heating circuit (10) and a second heating circuit (11), and in the second heating circuit (11) a second circulation pump (19) and a 3-way mixing valve (17) which can allow flow through a bypass (18) between the flow and return of the second heating circuit (11), as well as a balancing valve (16) are arranged, and the method comprises at least the following steps: a) determining a necessary first differential pressure (27) to operate the first heating circuit (10) in the design state, and b) adjusting a second predetermined target flow rate (24) in the heat generator circuit (13) and adjusting the first differential pressure (27) determined in step a) with the actuating position (25) of the balancing valve. (16) as an actuator.

Description

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

[0002] Heating systems typically have one or more heating circuits to heat or cool the rooms being supplied. Various options are available for implementing multiple heating circuits within a heating system. In systems with hydraulic decoupling, the appropriate heat transfer medium flow rate can be set independently and separately for each heating circuit. However, hydraulic decoupling is complex; for example, a system with one heat generator circuit and two heating circuits requires a hydraulic separator, three circulation pumps, and at least one flow rate sensor.

[0003] In contrast, systems without hydraulic decoupling are considerably simpler in design and therefore more cost-effective. For example, a heating system with two heating circuits and one heat generator circuit requires only one overflow valve, two circulation pumps, and two flow rate sensors. Hydraulic balancing in such systems can be achieved using the overflow valve. Two dedicated flow rate sensors are required for status detection, i.e., the distribution of heat transfer fluid flow rates between the two heating circuits, because the heating circuits influence each other.

[0004] Systems without hydraulic decoupling, which only use a volume flow sensor, are also known. However, such systems are metrologically under-determined. According to the state of the art, appropriate heat distribution between the two heating circuits is ensured by adjusting the overflow valve. However, because only one volume flow sensor is used in the heat generator circuit, the overflow valve cannot be adjusted based on measured values. According to the state of the art, the overflow valve is adjusted based on a pump performance diagram. For this purpose, the installer specifies a pulse-width modulated (PWM) signal at the circulation pump and sets a predetermined volume flow through trial and error. Using the resulting combination of volume flow and PWM signal from the circulation pump, the pressure loss can be determined and adjusted at the overflow valve.The pulse width modulated signal at the circulation pump can then be increased until the desired system flow rate is reached.

[0005] This method is time-consuming for the installer and often inaccurate. There is no feedback from the system regarding the precise distribution of the flow rates, and thus the heat distribution. Furthermore, there is no feedback that would allow an installer to determine whether the overflow valve is functioning properly.

[0006] Furthermore, an overflow valve is a mechanical and statically adjustable component that cannot respond to dynamic, variable heat demand. Furthermore, an overflow valve must be manually adjusted and thus located within the heater so that it is accessible from the outside, which limits the design freedom of a heater. Last but not least, an overflow valve can become clogged or fail, which is associated with high maintenance costs.

[0007] Based on this, the object of the invention is to propose a method for operating a hydraulically non-decoupled heating system with two heating circuits that can ensure a demand-based supply of the two heating circuits in full-load and partial-load operation with only one volume flow sensor, two circulation pumps, and without the use of an overflow valve. Furthermore, the method should make it possible to ensure the circulation of a minimum volume flow in the heat generator circuit and to respond to different heat requirements.

[0008] In addition, the invention should not increase the complexity of a heating system and require only minor structural changes, and possibly also reduce the necessary installation work for a heating system.

[0009] 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.

[0010] A method for operating a heating system contributes to this. The heating system has a heat generator circuit with a flow and a return, a first circulation pump, and a volume flow sensor for determining the volume flow delivered by the first circulation pump. The heat generator circuit is hydraulically connected to a first heating circuit and a second heating circuit. A second circulation pump, a 3-way mixing valve, which can flow through a bypass between the flow and return of the second heating circuit, and a balancing valve are arranged in the second heating circuit. The method comprises at least the following steps: a) Determining a necessary first differential pressure (also referred to as residual head) in order to operate the first heating circuit in the design state, and b) Adjusting a second predetermined target volume flow in the heat generator circuit by means of the volume flow sensor and adjusting the differential pressure determined in step a) by means of the circuit regulating valve.

[0011] In a regular process sequence, steps a) and b) are performed at least once in the specified order. Step a) can be performed at least once after commissioning of the heating system and serves to determine the required differential pressure for the design case. Step a) can also be repeated periodically or as needed. Step b) is used to adjust / locate a first setting position of the balancing valve, in which the volume flow delivered by the first circulation pump is distributed between the first and second heating circuits according to the design state.

[0012] The proposed method serves to ensure particularly precise and energy-efficient operation of a heating system according to the generic term.

[0013] The heating system can heat or cool a building. For this purpose, the heating system can be connected to a heating circuit in which a heat transfer medium can circulate. The heat transfer medium can, in particular, be heating water. The heating system can include a heat generator that can transfer heat to or extract heat from a heat generator circuit.

[0014] The heat generator can, in particular, be a heat pump capable of heating or cooling the heat transfer medium circulating in the heat generator circuit. The heat generator can also be a heating device designed to burn a fuel. The fuel to be burned can be, for example, natural gas or hydrogen.

[0015] The heat generator circuit of the heating system can have a first circulation pump that can pump the heat transfer medium. A volume flow sensor can also be present to measure the volume flow of heat transfer medium pumped in the heat generator circuit. The flow of the heat generator circuit can be connected to a flow of a first heating circuit and to a flow of a second heating circuit. Similarly, the return of the heat generator circuit can be connected to a return of the first heating circuit and a return of the second heating circuit. In this respect, the first heating circuit and the second heating circuit are two heating circuits arranged in parallel.

[0016] Heat consumers such as radiators or surface heating systems can be arranged in the first and second heating circuits. In particular, one or more radiators controlled by a thermostatic valve can be arranged in the first heating circuit, which can also be referred to as a direct heating circuit. In particular, at least one surface heating system can be present in the second heating circuit, which can also be referred to as a mixed heating circuit. In particular, the first heating circuit can exclusively contain radiators controlled by a thermostatic valve, and the second heating circuit can exclusively contain one or more surface heating systems.

[0017] The second heating circuit also contains a balancing valve that can be controlled electrically or electronically and can be moved by an actuator into a setting position of the balancing valve, which ranges, in particular continuously, from a complete closing to a complete opening of the balancing valve. The electrically controllable balancing valve can be connected to a process-executing device, such as a control and regulation device.

[0018] The second heating circuit also includes a three-way mixing valve that can flow through a bypass located between the flow and return of the second heating circuit. The three-way mixing valve can therefore adjust the flow temperature of the second heating circuit. The three-way mixing valve can also be electrically or electronically controlled and connected to a process-executing device, such as a control unit. Furthermore, the second heating circuit includes a temperature sensor for detecting the flow temperature of the second heating circuit, which allows the flow temperature set by the three-way mixing valve to be detected. Last but not least, the second heating circuit can include a second circulation pump configured to circulate the heat transfer medium in the second heating circuit.

[0019] In the second heating circuit, the balancing valve can be arranged upstream of the three-way mixing valve, and the three-way mixing valve can be arranged upstream of the temperature sensor for measuring the flow temperature. The second circulation pump can be arranged downstream of the three-way mixing valve, as seen in the flow direction.

[0020] The first and / or second circulation pump can, in particular, be a controllable circulation pump, which can also be connected to the control and regulation device as a process-executing device. The first circulation pump can be configured to output a generated differential pressure, for example, via a data transmission connection. The transmission can, for example, be made to a control and regulation device that executes the process.

[0021] The heating system is therefore a system without hydraulic decoupling with two parallel heating circuits, which is underdetermined in terms of measurement technology.

[0022] According to step a), a necessary first differential pressure can be determined, which is required to operate the first heating circuit in the design state. The first differential pressure indicates a differential pressure (a residual head) that is necessary to operate the first heating circuit in the design state. With a first setting position of the circuit regulating valve corresponding to the first differential pressure, this results in a volume flow in the first heating circuit corresponding to the design state, which, with a predetermined temperature spread between the flow and return lines, can transfer the heat flow required for supply and thus meet the heating requirement in the first heating circuit. The volume flow in the second heating circuit can be adjusted by the dedicated second circulation pump (circulation pump) and the three-way mixing valve or bypass, independently of the volume flow flowing through the circuit regulating valve.However, the volume flow through the balancing valve must be at least large enough to provide sufficient heat flow in the design state with the three-way mixing valve fully open (and thus the bypass closed). The required heat flows and the associated required volume flows can be determined in advance as part of a heating load calculation. When performing step a), the balancing valve, in particular, can be completely closed.

[0023] The term "design state" refers to a state in which the heating system must transfer maximum heat, meaning all consumers are fully open. The required flow rates in the first and second heating circuits should be set during steps a) and b) by adjusting the balancing valve and thus by dividing the flow rate of the heat generator circuit between the first and second heating circuits.

[0024] When planning a heating system, it should be designed to ensure that the system is sufficiently dimensioned to supply a building. This usually involves using data relating to the specific climatic conditions at the location and the structural requirements of the specific building / the specific rooms to be supplied. During the design process, for example, the nominal output of a heat generator and the size of a consumer (convector, radiator, underfloor heating, etc.) for each room to be supplied can be determined in order to ensure that the building is reliably supplied by the heating system. Based on the design of the heating system (in particular its dimensions, equipment and / or operating mode), a specified heating and / or cooling output can be set or ensured under the predetermined conditions.

[0025] For example, during the design phase of a heating system, a (maximum) output of a heat generator can be determined and the consumers (radiators, convectors, surface heating (underfloor or wall heating elements)) to be connected via a heating circuit can be dimensioned to ensure a reliable heat supply under the specific climatic conditions at the location and the structural characteristics of the building to be supplied (particularly its thermal insulation). Various design methods are known for their implementation. For example, the specific wall, window, ceiling, and / or floor areas for each room to be supplied can be used to determine the specific (output) requirement and then select a specific consumer (e.g., radiators).According to another (approximate) method, (only) the floor area of ​​all rooms to be supplied and approximate information on the building's structural conditions (thermal insulation or heat losses) can be taken into account to determine the demand and dimension the heating system. The design state is characterized by the maximum heat flow to be transferred, with which the building or the rooms to be supplied can be heated to a specified temperature. In the design state, a temperature spread between the flow and return of the heat generator circuit, as well as a second target volume flow for the heat generator circuit and / or a first target volume flow for the first heating circuit, can be specified.In the design state, the second target flow rate in the heat generator circuit can be composed of the (target) flow rate in the first and second heating circuits and the flow rate flowing through the bypass of the second heating circuit. The second target flow rate can take into account the heat demand of the second heating circuit, and the second heating circuit can be operated in a self-regulating manner. The second circulation pump can be operated to regulate the differential pressure, and a flow temperature can be regulated / set via the three-way mixing valve.

[0026] To carry out step a), a method comprising the following method steps can be used: a1) Completely closing the circuit regulating valve, whereby the entire volume flow pumped by the first circulation pump flows from the heat generator circuit into the first heating circuit, b1) Adjusting a predetermined first target volume flow for the first heating circuit by means of the first circulation pump and the volume flow sensor in the heat generator circuit, c1) Recording a first pump operating parameter of the first circulation pump, which is characteristic of the pump operating state adjusted in step b1), d1) Determining a first pump differential pressure (delivery head) of the first circulation pump based on the first pump operating parameter determined in step c1) and a predetermined pump characteristic of the first circulation pump, and e1) Determining a first differential pressure (residual delivery head) based on the first pump differential pressure determined in step d1) and a predetermined pressure loss characteristic of the heat generator circuit.

[0027] The process steps a1) to e1) can be carried out at least once in the specified order.

[0028] According to step a1), the balancing valve can be completely closed. This closes the flow of the second heating circuit, and the entire volume flow of the heat generator circuit flows through the first heating circuit.

[0029] According to a step b1), a predetermined first target volume flow of the design state for the first heating circuit can be regulated by means of the first circulation pump and the volume flow sensor in the heat generator circuit.

[0030] According to step c1), a first pump operating parameter of the first circulation pump can be detected, which is characteristic of the pump operating state adjusted in step b1). The first pump operating parameter can, in particular, be a PWM signal used to control the first circulation pump, or a pump speed. The detected first pump operating parameter is thus characteristic of the first target volume flow adjusted in step b1) with the balancing valve fully closed.

[0031] According to step d1), a first pump differential pressure (a delivery head) of the first circulation pump can be determined for the first pump operating parameter determined in step c1) with the aid of a predetermined pump characteristic. The predetermined pump characteristic can be a predetermined pump characteristic curve that establishes a relationship between the pumped volume flow, the generated pump differential pressure, and the pump operating parameter (a PWM signal or a pump speed). The first pump differential pressure is thus determined at the time at which the pump operating state of step b1) was adjusted. The first pump differential pressure of the first circulation pump refers to the pressure difference generated by it between the flow and return in the heat generator circuit at a time at which the pump operating state of step b1) was adjusted.The pump differential pressure is composed of the pressure drop in the heat generator circuit and the first differential pressure required to operate the first heating circuit in the design state, or represents the sum of both in the steady state. The pressure drop in the heat generator circuit is determined by a predetermined pressure loss characteristic, so that in step e1), the first differential pressure (residual head) for operating the first heating circuit in the design state can be determined. Furthermore, the first differential pressure dp in the design state can be used to determine the hydraulic resistance. R hyd of the first heating circuit. The hydraulic resistance model describes the relationship between pressure loss (differential pressure) and the volume flow imposed by the differential pressure V̇ HK in the first heating circuit, even with flow rates that deviate from the design conditions. The relationship can be described as follows: R hyd = dp V ˙ HK 1 2

[0032] According to one embodiment, step b) can be carried out by performing at least the following sub-steps: a2) adjusting a predetermined second target volume flow in the heat generator circuit by means of the volume flow sensor of the heat generator circuit and the first circulation pump, and b2) adjusting the first differential pressure determined in step a) at the predetermined first target volume flow, wherein the circuit regulating valve is an actuator.

[0033] Steps a2) and b2) can, in particular, be carried out in parallel and identically. Steps a2) and b2) can be carried out continuously in order to operate the heating system in the design state. If a largely steady state has been established during the execution of steps a2) and b2), according to one embodiment, a first setting position of the circuit regulating valve and, if applicable, the hydraulic resistance of the first heating circuit can be recorded and, if applicable, stored and / or stored in a control system. For example, the first setting position can be stored in a memory of a control and regulation device executing the process.

[0034] According to step a2), a predetermined second target flow rate can be adjusted in the heat generator circuit using the heat generator circuit's flow rate sensor and the first circulation pump. The second target flow rate can correspond to the target flow rate of the heat generator circuit in the design state.

[0035] According to step b2), the differential pressure determined in step a) can be adjusted at the specified first target flow rate, with the opening position of the balancing valve serving as a control variable. Typically, the balancing valve (which is closed after performing steps a1) to e1) is opened until the differential pressure determined in step a) is set. At the nominal flow rate, the pressure loss of the first heating circuit should be greater than the pressure loss of the second heating circuit with the balancing valve fully open.

[0036] In this case, a largely static state can arise, which can be characterized by a first setting position of the balancing valve.

[0037] As a result of carrying out steps a) and b), a first setting position is now set on the circuit regulating valve; with the set target volume flow of the design state in the heat generator circuit, the desired volume flows necessary for heat supply in accordance with the design state can be set in the first and second heating circuits.

[0038] Particularly advantageously, steps a) and b) or a1) to e1) as well as a2) and b2) can be carried out entirely with computer support. Adjusting an overflow valve is thus unnecessary, and in fact, the presence of an overflow valve can be completely dispensed with.

[0039] According to one embodiment, in the context of carrying out step b), the first circulation pump can be regulated to a target volume flow by means of the volume flow sensor and the second heating circuit can be regulated to a constant, predetermined flow temperature and a constant predetermined volume flow by means of the second circulation pump, the three-way mixing valve and the temperature sensor, which is configured to detect a flow temperature of the second heating circuit.

[0040] Assuming that several radiators with a thermostatic valve are arranged in the first heating circuit, operating the valve with a constant, regulated differential pressure is particularly advantageous, since even after individual thermostatic valves are closed, the remaining open radiators are each operated at a constant flow rate. This means that radiators arranged in the first heating circuit are always supplied with the same flow rate, even after one or more thermostatic valves are closed. Furthermore, hydraulic balancing of the radiators arranged in the first heating circuit can ensure that the desired flow rate is achieved in each (open) radiator at a constant differential pressure.This flow rate can correspond to the flow rate from the heating load calculation (design), which, at a given temperature difference between the flow and return lines, provides a flow rate corresponding to the heating load in the design state. If the first heating circuit were operated with a constant flow rate, closing individual thermostatic valves would lead to an increase in the flow rate in the remaining open radiators, which could be accompanied by unpleasant noise.

[0041] According to one embodiment, while step b) is being carried out, the first circulation pump can regulate a constant volume flow of the design state by means of the volume flow sensor, and the second heating circuit can be regulated to a constant, predetermined flow temperature in the second heating circuit by means of the second circulation pump, the three-way mixing valve and a temperature sensor designed to detect a flow temperature of the second heating circuit. Thus, if a predetermined minimum volume flow is available in the flow direction downstream of the circuit regulating valve, the second heating circuit can be operated as described above. If there is an excess volume flow, for example due to individual thermostatic valves in the first heating circuit being closed, this can be diverted from the circuit regulating valve by flowing through the bypass directly into the return flow of the second heating circuit orThe heat generator circuit can be dissipated without affecting the second heating circuit. This ensures a constant flow temperature in the second heating circuit, which is necessary for underfloor heating systems.

[0042] According to one embodiment, in step c), the volume flow to be regulated can be reduced as needed, and the balancing valve can remain in the first setting position. In other words, if a reduced heat demand is detected, for example, due to a decrease in the detected temperature difference between the flow and return of the heat generator circuit, the volume flow delivered by the first circulation pump can be reduced as needed. In this case, control of the pressure difference with the balancing valve as the actuator is terminated, and the balancing valve is moved to the first setting position and left there. This advantageously meets a reduced heat demand. A heat pump as the heat generator could detect the decreasing temperature difference between the flow and return and reduce the value of the target volume flow to be regulated in order to increase the temperature difference.A lower return temperature can lead to a lower condensation temperature in the condenser, which can have a positive effect on the efficiency of the heat pump. As a result, the absolute value of the flow rate in the heat generator circuit as well as in the first and second heating circuits would decrease. The distribution of the flow rate from the heat generator circuit to the first and second heating circuits remains approximately constant.

[0043] According to one embodiment, alternatively, in a step c), the volume flow in the heat generator circuit can be reduced as needed, and based on the subsequently reduced volume flow in the first heating circuit, a required second differential pressure can be determined using the largely constant hydraulic resistance of the first heating circuit, and the circuit regulating valve can be controlled to the second differential pressure. This can represent a more comprehensive control strategy that uses the volume flow proportionally reduced in the first heating circuit when the volume flow in the heat generator circuit is reduced. With this reduced volume flow setpoint of the first heating circuit, a new required second differential pressure can be determined using the hydraulic resistance approach described above, at which second differential pressure the reduced volume flow in the first heating circuit will occur.

[0044] According to one embodiment, in a step d), a second setting position of the balancing valve, which indicates a minimum opening width of the balancing valve, can be determined by carrying out at least the following steps: a3) Setting a predetermined minimum output of the first circulation pump; b3) Closing the circuit regulating valve until a predetermined minimum volume flow is determined at the device for determining the volume flow in the heat generator circuit, and c3) Detecting the second setting position of the circuit regulating valve as the minimum opening position.

[0045] Steps a3) to c3) can be performed at least once in the specified order. During this process, the first heating circuit should be completely shut off. For this purpose, a corresponding zone valve could be closed automatically, for example. When performing step b3), the balancing valve should be opened sufficiently to ensure the minimum flow rate at the maximum speed (power) of the first circulation pump. After this step, the second setting position of the balancing valve is known, which can ensure the circulation of a minimum flow rate in the heating circuits.The minimum flow rate is particularly necessary to be able to react when heating requirements are detected, for example, by opening a thermostatic valve, to be able to cope with a sudden drop in the return temperature by extracting heat, and also to create a way to extract heat from the heating system. This is necessary, for example, to initiate and carry out a defrosting process on an evaporator of a heat pump used as a heat generator. The minimum flow rate can be determined or calculated in advance through tests. Circulation of the heat transfer medium must also be ensured if an additional (electric) heating element, if present, couples heat into a heating circuit.

[0046] According to a further aspect, a heating system is also proposed, which comprises means for carrying out a method proposed here. The heating system can also have a heat generator circuit with a first circulation pump and a volume flow sensor. The heat generator circuit can also be hydraulically connected to a first heating circuit and a second heating circuit. A second circulation pump and a 3-way mixing valve can be arranged in the second heating circuit, which can flow through a bypass between the flow and return of the second heating circuit. In addition, a circuit regulating valve and a temperature sensor for detecting a flow temperature of the second heating circuit can be arranged in the second heating circuit.

[0047] According to a further aspect, a control and regulating device, in particular of a heating system, is also proposed, configured to carry out a method presented here. For this purpose, the control and regulating device can, for example, have or be equipped with a processor. In this context, the processor can, for example, execute the method stored in a memory (of the control and regulating device). Data necessary for carrying out a method proposed here, for example data of the design state, a pump characteristic curve of the first circulating pump, a pressure loss characteristic of the heat generator circuit, as well as data acquired during the implementation of the method, such as a first and second setting position of the circuit regulating valve and a recorded or determined differential pressure, can advantageously also be stored in the memory (of the control and regulating device).

[0048] According to a further aspect, a computer program (product) is also proposed, comprising instructions that cause a computer to perform a method presented here. When executed by a computer, the computer program can, in particular, perform all or part of the proposed method steps.

[0049] For this purpose, the computer program may establish a connection to a network, such as the Internet, and / or a data connection to a mobile device and / or to a (control and regulation device) of an air conditioning unit.

[0050] For clarification, it should be noted that when referring to a volume flow, this refers to a flow rate. In this respect, it can also refer to a mass flow, which can be converted into a volume flow, and vice versa, given knowledge of the density and temperature of the circulating heat transfer medium.

[0051] 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.

[0052] The details, features, and advantageous embodiments discussed in connection with the method may also be present in the computer program, the control device, and / or the heating system proposed here, and vice versa. In this respect, reference is made in full to the explanations therein for a more detailed characterization of the features.

[0053] Thus, a method for operating a heating system, a computer program, a control device, and a heating system are provided that at least partially solve the problems described with reference to the state of the art. In particular, the method, the computer program, the control device, and the heating system at least contribute to proposing a particularly precise and energy-efficient operation of a heating system with at least two heating circuits that are not hydraulically decoupled and are underdetermined by measurement technology.

[0054] In addition, the invention can be implemented particularly easily since no structural changes to a heating system are required and a purely software-based implementation of the invention appears possible.

[0055] 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. They show: Fig. 1 : a sequence of a procedure proposed here, Fig. 2 : a heating system proposed here, and Fig. 3 : Parameter curves that can occur with a procedure proposed here.

[0056] Fig. 1 shows, by way of example and schematically, a sequence of a method proposed here. The method serves for efficient and precise operation of the heating system 1. The sequence of steps a) and b) shown in blocks 110 and 120 can occur in a regular method sequence. Likewise, in a regular method sequence, the shown sequence of the sub-steps a1), b1), c1), d1) and e1) to be carried out according to an embodiment of step a), which are shown in blocks 130, 140, 150, 160 and 170, can result. Analogously, according to an embodiment, step b) can result by carrying out the sub-steps a2) and b2), which are shown in blocks 180 and 190.

[0057] Fig. 2 shows, by way of example and schematically, a heating system 1 proposed here. This comprises a heat generator 2, which can be designed here as a heat pump with an outdoor unit 3 and a condenser 4. The condenser 4 can be configured to transfer heat to a heat generator circuit 13. A first circulation pump 8 and a volume flow sensor 5 are arranged in the heat generator circuit 13. A flow line 6 and a return line 7 of the heat generator circuit 13 can be connected to a first heating circuit 10 and a second heating circuit 11, wherein the first heating circuit 10 and the second heating circuit 11 are arranged in parallel. The first heating circuit 10 can supply several radiators arranged in parallel with thermostatic valves. A circuit regulating valve 16 can be arranged upstream of the second heating circuit 11.A second circulation pump 19 and a three-way mixing valve 17, as well as a bypass 18 between the balancing valve 16 and the return of the heat generator circuit 13, can be arranged in the second heating circuit 11. Furthermore, a temperature sensor 20 can be arranged in the second heating circuit 11, which can measure the flow temperature of the second heating circuit 11. The heating system 1 can also include a domestic hot water supply 14, which can be coupled to the heat generator circuit 13 by means of a three-way valve 9 and a storage tank 15.

[0058] The heating system 1 can comprise a control and regulation device 29, which can be configured to carry out a method proposed here. For this purpose, the control and regulation device 29 can be electrically connected to at least the balancing valve 16, the three-way mixing valve 17, the temperature sensor 20, the first circulation pump 8, the second circulation pump 19, and the volume flow sensor 5. It is understood that the control and regulation device 29 can be electrically connected to additional sensors of the heat generator 2, the domestic hot water supply 14, and other devices of the heating system 1 in order to regulate and control them.

[0059] Fig. 3 shows exemplary parameter curves that can be achieved when implementing steps a) and b) of a method proposed here. The curve of a PWM signal 21 (pulse-width modulated signal) of the first circulation pump 8, the curve of the volume flow 22 detected by the volume flow sensor 5, the curve of the setting position 25 of the balancing valve 16, and the differential pressure 26 are shown.

[0060] In block 110, according to step a), a first differential pressure 27 can be determined, which is required to operate the first heating circuit 10 in the design state. According to one embodiment, the following substeps a1), b1), c1), d1, and e1) shown in blocks 130, 140, 150, 160, and 170 can be performed for this purpose.

[0061] In block 130, according to step a1), the circuit regulating valve 16 can be completely closed, whereby the entire volume flow 22 pumped by the first circulation pump 8 flows from the heat generator circuit 13 into the first heating circuit 10. This can be seen in the course of the setting position 25 of the circuit regulating valve 16 by setting the closing position 30.

[0062] In block 140, according to step b1), a predetermined first target volume flow 23 for the first heating circuit 10 can be adjusted using the first circulation pump 8 and the volume flow sensor 5 in the heat generator circuit 13. The first target volume flow 23 can be the target volume flow of the first heating circuit 10 in the design state, which was determined according to a heating load calculation. The first target volume flow 23 is established as recognizable by the profile of the volume flow 22.

[0063] The corresponding PWM signal 21 of the first circulation pump 8 can be recorded as the first pump operating parameter 31 in block 150 according to step c1) and stored in a memory.

[0064] In block 160, according to step d1), a pump differential pressure 12 between the inlet and outlet of the first circulation pump 8 can be determined based on the first pump operating parameter 31 determined in step c1) and a predetermined pump characteristic. The pump characteristic is a characteristic curve specific to the specific pump, which establishes a relationship between the volume flow 22, the PWM signal 21, and the discharge head or the pump differential pressure generated by the pump.

[0065] In block 170, according to step e1), a first differential pressure 27 (i.e., a value of the pump differential pressure 12) can be determined based on the pump differential pressure 12 (delivery head) determined in step d1) (block 160) and a pressure loss determined by the predetermined pressure loss characteristic of the heat generator circuit 13. Thus, the first differential pressure 27 can be determined, which is composed of the pump differential pressure and the pressure loss of the heat generator circuit 13.

[0066] In block 120, according to step b), a second predetermined target volume flow 24 in the heat generator circuit 13 can be adjusted by means of the volume flow sensor 5, and the first differential pressure 27 determined in step a) can be adjusted by means of the circuit regulating valve 16. Two control circuits can be used for this purpose.

[0067] In block 120, step b) can be executed according to one embodiment by performing the substeps a2) and b2) shown in blocks 180 and 190. Substeps a2) and b2) can be executed in particular in parallel or simultaneously.

[0068] In block 180, according to step a2), a predetermined second target volume flow 24 in the heat generator circuit 13 can be adjusted by means of the volume flow sensor 5 of the heat generator circuit 13 and the first circulation pump 8. In the Fig. 3 a corresponding increase in the PWM signal 21 of the first circulation pump 8 and an increase in the volume flow 22 can be seen.

[0069] At the same time, in block 190 according to step b2), the first differential pressure 27 determined in step a) can be adjusted using the balancing valve 16 as the actuator. Fig. 3 As can be seen, the setting position 25 of the balancing valve 16 is changed so that it opens until a first setting position 32 has been adjusted, at which the course of the differential pressure 26 is adjusted to the first differential pressure 27.

[0070] In the example according to Fig. 3 A design condition of 500 liters per hour was realized in the first heating circuit 10 and potentially in the second heating circuit 11. The heating system 1 can now be operated energy-efficiently with the volume flows 22 provided for in the design condition. Fig. 3 also shows a tested volume flow 28 of the first heating circuit, which corresponds to the first target volume flow 23 set in step a1), thus confirming the success of the process. The tested volume flow 28 was determined externally as part of a laboratory test.

[0071] According to one embodiment, the second heating circuit 11 can set a flow temperature by means of the three-way mixing valve 17 and a volume flow by means of the second circulation pump 19.

[0072] According to one embodiment, according to an optional step c), when a reduced heat demand is detected, the first setting position 32 on the circuit regulating valve 16 can be fixed and the power of the first circulation pump 8 can be reduced. List of reference symbols

[0073] 1Heating system 2Heat generator 3Outdoor unit 4Condenser 5Flow rate sensor 6Flow 7Return 8First circulation pump 9Three-way valve 10First heating circuit 11Second heating circuit 12Pump differential pressure 13Heat generator circuit 14Domestic hot water supply 15Storage tank 16Balancing valve 17Three-way mixing valve 18Bypass 19Second circulation pump 20Temperature sensor 21PWM signal first circulation pump 22Flow rate 23First target flow rate 24Second target flow rate 25Balancing valve setting position 26Differential pressure 27First differential pressure 28Tested flow rate first heating circuit 29Control unit 30Closing position 31First pump operating parameter 32First setting position

Claims

1. A method for operating a heating system (1), comprising a heat generator circuit (13) with a first circulation pump (8) and a volume flow sensor (5), wherein the heat generator circuit (13) is hydraulically connected to a first heating circuit (10) and a second heating circuit (11), and a second circulation pump (19), a 3-way mixing valve (17), which can flow through a bypass (18) between the flow and return of the second heating circuit (11), and a circuit regulating valve (16) are arranged in the second heating circuit (11), and the method comprises at least the following steps: a) determining a necessary first differential pressure (27) in order to operate the first heating circuit (10) in the design state, and b) adjusting a second predetermined target volume flow (24) in the heat generator circuit (13) and adjusting the first differential pressure (27) determined in step a) with the setting position (25) of the balancing valve (16) as an actuator.

2. The method according to claim 1, wherein step a) is carried out by carrying out at least the following sub-steps: a1) completely closing the circuit regulating valve (16), whereby the entire volume flow (22) from the heat generator circuit (13) flows through the first heating circuit (10), b1) adjusting a predetermined first target volume flow (23) by means of the first circulation pump (8) in the heat generator circuit (13), c1) detecting a first pump operating parameter (31) of the first circulation pump (8), which is characteristic of the pump operating state adjusted in step b1), d1) determining a first pump differential pressure (12) of the first circulation pump (8) based on the first pump operating parameter (31) determined in step c1) and a predetermined pump characteristic,and e1) determining a first differential pressure (27) by means of the first pump differential pressure (12) determined in step d1) and a predetermined pressure loss characteristic of the heat generator circuit (13).

3. Method according to one of the preceding claims, wherein step b) can be carried out by carrying out at least the following sub-steps: a2) regulating a predetermined second target volume flow (24) in the heat generator circuit (13) by means of the volume flow sensor (5) of the heat generator circuit (13) and the first circulation pump (8), and b2) regulating the first differential pressure (27) determined in step a), with the setting position (25) of the circuit regulating valve (16) as the actuator, so that a first setting position (32) of the circuit regulating valve (16) results.

4. Method according to one of the preceding claims, wherein, when carrying out step b), the first differential pressure (27) to be regulated is determined by means of a pump differential pressure (12) generated by the first circulation pump (8) and a predetermined pressure loss characteristic of the heat generator circuit (13).

5. Method according to one of the preceding claims, wherein during the implementation of step b) the first circulation pump (8) regulates a constant second target volume flow (24) in the second heating circuit (11) by means of the volume flow sensor (5) and the second heating circuit (11) sets a constant, predetermined flow temperature and a predetermined volume flow in the second heating circuit (11) by means of the second circulation pump (19) and the three-way mixing valve (17) and a temperature sensor (20) configured to detect a flow temperature of the second heating circuit (11).

6. Method according to one of the preceding claims, wherein in a step c) the volume flow (22) to be regulated in the heat generator circuit (13) is reduced as required and the circuit regulating valve (16) remains in the first setting position (32).

7. Method according to one of claims 1 to 5, wherein in a step c) the volume flow (22) to be regulated in the heat generator circuit (13) is reduced as required and, on the basis of the subsequently reduced volume flow in the first heating circuit (10), a second differential pressure required for this purpose is determined by means of the hydraulic resistance and the circuit regulating valve (16) is regulated to the second differential pressure.

8. Method according to one of the preceding claims, wherein in a step d) a second setting position of the circuit regulating valve (16), which indicates a minimum opening width of the circuit regulating valve (16), is determined by carrying out at least the following steps: a2) setting a predetermined minimum power of the first circulation pump (8); b2) closing the circuit regulating valve (16) until the volume flow sensor (5) in the heat generator circuit (13) detects a predetermined minimum volume flow, and c2) detecting the second setting position of the circuit regulating valve (16) as the minimum opening position which is not undershot.

9. The method according to claim 8, wherein steps a2) to c2) are carried out once and the detected second setting position is stored and / or stored in a control system.

10. Method according to one of the preceding claims, wherein in the first heating circuit (10) at least one radiator is supplied with a thermostatic valve.

11. Method according to one of the preceding claims, wherein at least one surface heating system is supplied in the second heating circuit (11).

12. Method according to one of the preceding claims, wherein the heat generator (2) is a heat pump.

13. A heating system (1), comprising: - a heat generator (2) arranged in a heat generator circuit (13) with a first circulation pump (8) and a volume flow sensor (5), - a first heating circuit (10) and a second heating circuit (11) arranged in parallel and hydraulically connected to the heat generator circuit (13), - a second circulation pump (19) arranged in the second heating circuit (11), and a three-way mixing valve (17) configured to control a flow through a bypass (18) between a flow line and a return line of the second heating circuit (11), - an electrically controllable circuit regulating valve (16) arranged in the second heating circuit (11), - a temperature sensor (20) configured to detect a temperature of the flow line (6) of the second heating circuit (11), - and means configured to carry out a method according to one of claims 1 to 12.

14. Computer program comprising instructions which cause a heating system (1) according to claim 13 to carry out a method according to one of claims 1 to 12.

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