Method for operating a heating device, computer program, storage medium, regulating and control device, heating device and use of a signal

Abstract

A method for detecting gas in a heating circuit (2) of an air conditioning unit (1) is proposed. The heating circuit (2) includes a circulation pump (5) for circulating a liquid heat transfer fluid within the heating circuit (2). The power consumption of the circulation pump (5) is measured, and if it falls below a power limit (19), a significant proportion of gas is inferred in the heating circuit (2). The circulation pump (5) is operated at a predetermined test speed when the power consumption is measured, and / or the power limit (19) is defined as a function of the speed of the circulation pump (5). Furthermore, a tolerance (20) for the power consumption is included in the comparison with the power limit (19). Changes in the measured power consumption are determined by regularly measuring the power consumption at intervals, and the tolerance (20) is adjusted accordingly.

Description

[0001] The invention relates to a method for detecting gas in a heating circuit of an air conditioning unit, a computer program, a control and regulating device and an air conditioning unit.

[0002] Heating circuits are designed to transport heat, for example, from a heating device to a consumer such as a radiator or underfloor heating, and contain a heat transfer medium, often water, for this purpose. A heating circuit may contain air or other gas that restricts heat transfer, which may have entered the heating circuit during filling or through leaks. Therefore, heating circuits must be vented / degassed regularly to ensure proper operation and, in particular, efficient heat transfer. In addition to restricting heat transfer, gas or gas bubbles in a heating circuit can also cause unwanted noise emissions, for example, in the area of ​​a circulation pump.

[0003] Methods are known for detecting gas in a heating circuit filled with a liquid heat transfer medium. A sensor can be used to detect gas in a liquid stream.

[0004] As an example, DE 20 2022 100 810 U1 presents a heat pump system with a heat pump in which a consumer circuit is connected to a refrigerant circuit of the heat pump. A sensor located in the consumer circuit for detecting gaseous refrigerant can initiate a safety measure if a threshold value is exceeded. This safety measure can include, among other things, a degassing process. The disadvantage is that the use of a sensor is complex and there is also a risk of sensor failure. A similar process is described in DE 10 2022 112 153 A1.

[0005] EP 3 275 524 A1 attempts to solve this problem by means of a vacuum degassing device for a liquid and a method for its operation, in particular for a cooling circuit of a fuel cell. For this purpose, a degassing chamber is provided in which the liquid to be degassed is expanded by means of a vacuum generation device, allowing dissolved gases to escape. In addition, the proposed method can be used to monitor and / or determine a gas content or gas saturation state of the liquid. However, maintaining and introducing the liquid into a degassing chamber, combined with the generation of a vacuum for the chamber, is complex and unsuitable for a building's heating circuit.

[0006] EP 3 211 330 A1 describes a method and a device for the automatic detection of air bubbles or air inclusions in a system in which a fluid is circulated by a circulation pump. The pressure in the area of ​​an expansion tank is measured. In addition, other system parameters related to one or more measured pressure changes are analyzed, and it is checked whether these are within specified limits. A disadvantage is that measuring the pressure in the expansion tank is complex.

[0007] DE 10 2014 226 450 A1 describes a method for performing automatic hydraulic balancing of a heating system. A diagnostic procedure can assign temperature sensors in the return line to heat consumers and check whether the heat consumers are receiving sufficient water or whether they contain air. However, the diagnostic procedure does not allow for sufficiently precise detection of air in the heating circuit.

[0008] Based on this, the object of the invention is to propose a method for detecting gas in a heating circuit of an air conditioning unit, a computer program, a control and regulation device, and an air conditioning unit that at least partially overcome the described problems of the prior art. In particular, a simple, long-term stable, safe, and cost-effective method for detecting gas in a heating circuit is to be provided. Furthermore, the method should require as few or no structural changes to an air conditioning unit as possible and be suitable for being carried out at least partially automatically. The method should also be suitable for implementation with minimal effort on existing air conditioning units.

[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 detecting gas in a heating circuit of an air conditioning unit contributes to this. The heating circuit comprises at least one circulating pump for circulating a liquid heat transfer medium. The power consumption of the circulating pump is recorded and, if a (specified) power limit is undershot, a conclusion is drawn about a relevant proportion of gas in the heating circuit. The circulating pump is operated at a specified test speed when the power consumption is recorded and / or the power limit is specified as a function of the speed of the circulating pump. In addition, a tolerance of the power consumption is included in a comparison with the power limit, a change in the recorded power consumption is determined by regular, time-spaced recording of the power consumption, and the tolerance is adjusted based on the change.

[0011] The method can be performed continuously, continuously, at intervals, and / or at regular intervals while the air conditioning unit is operating. The method is used, in particular, to detect gas components or gas bubbles in a heat transfer medium circulating in a heating circuit. The heat transfer medium can, in particular, be heating water. The gas to be detected can, in particular, be air. However, it can also be other gases, such as the refrigerant of a cooling circuit of an air conditioning unit designed as a heat pump.

[0012] An air conditioning unit is a device for heating or cooling a building or rooms within it. For example, the air conditioning unit can be a (gas-powered) heater designed to burn a combustible gas, such as natural gas or hydrogen, with the addition of ambient air and generate thermal energy, for example, to heat a heat transfer medium in a heating circuit or to provide hot water. The air conditioning unit can also be an air conditioning system or a heat pump system. The heat pump can be designed as a split heat pump with an outdoor unit and an indoor unit, or as a monoblock. The air conditioning unit can include a heat exchanger that can transfer heat to or extract heat from the heating circuit.

[0013] It is proposed to record the power consumption of the circulation pump in the heating circuit. As the proportion of gas in the heating circuit increases, the power consumption of the circulation pump decreases because less heat transfer medium is pumped. By comparing the recorded power consumption of the circulation pump with a power limit value, a relevant proportion of gas in the heating circuit can be identified. A relevant proportion of gas in the heating circuit refers to a proportion at which an impairment of the operation of the air conditioning unit and / or a relevant restriction of heat transport is to be expected. To ensure comparability, the circulation pump can be set to a test speed to record the power consumption. For this purpose, one or more test speeds and corresponding power limit values ​​can be stored in a memory of the air conditioning unit or a control unit of the air conditioning unit.Alternatively or cumulatively, the power limit can be specified as a function of the circulation pump's speed. The power consumption of a circulation pump can be present as a parameter in the pump control system and / or can be determined by measuring current and voltage.

[0014] The specified tolerance is included in the comparison of power consumption and the power limit. The tolerance can compensate for fluctuations in the recorded power consumption due to operating conditions or environmental parameters. The tolerance can be included, for example, by subtracting it from the power limit. Alternatively, it is also possible to store the power limit with the included tolerance and compare it with the recorded power consumption of the circulation pump during the process.

[0015] It has been shown that the hydraulic pressure loss in a heating circuit can increase, for example due to contamination or calcification. As a result, the power consumption of the circulation pump decreases gradually over a longer period of time. To avoid the resulting incorrect detection of gas in the heating circuit, changes in the recorded power consumption are determined by regularly and spaced recordings of the power consumption and the tolerance is adjusted to compensate for the change. Since the gradual change in power consumption occurs over a long period of time, often several years, a sensible time interval for recording power consumption can be weekly or monthly. By averaging the recorded power consumption over the long term, the effects of gas in the heating circuit on the recorded power consumption can also be averaged out.Alternatively or cumulatively, the recording of power consumption can also be triggered by an event, for example degassing of the heating circuit.

[0016] According to an advantageous embodiment, information about the circulation pump's power consumption falling below the performance limit and / or the detection of a relevant amount of gas in the heating circuit can be displayed on a display device, made available for retrieval via a network, and / or sent as a message. The network can, in particular, be the internet. This advantageously allows a user, system operator, and / or a specialist company to be informed, and if necessary, a maintenance appointment for a venting system can be scheduled and carried out independently.

[0017] According to one embodiment, a degassing process can be initiated if the power consumption of the circulation pump falls below the power limit and / or if a relevant proportion of gas is detected in the heating circuit.

[0018] According to a further embodiment, degassing of the heating circuit can be achieved by varying the speed of a circulation pump in the heating circuit. By varying the speed of the circulation pump, turbulent flows can be promoted or generated, with the resulting negative pressure areas promoting the outgassing of gases (air, refrigerant) from the heat transfer medium. The resulting gas bubbles can be collected in a corresponding area of ​​the heating circuit and removed from the heating circuit by opening a valve in this area, particularly automatically.

[0019] The term "degassing" here refers to the extensive or virtually complete removal of gaseous substances from a heating circuit, particularly the removal of air. Other gaseous substances such as fuel gas or refrigerant (e.g., R290) may also be present, which can enter the heating circuit through a leak in a heat exchanger from a connected refrigeration circuit and are removed in the process.

[0020] According to a further aspect, an air conditioning unit is proposed, which comprises at least one heating circuit and a circulation pump, as well as means adapted to carry out the steps of a method proposed here or suitable for carrying out a method proposed here. In particular, the air conditioning unit is configured to carry out a method proposed here.

[0021] According to a further aspect, a computer program is also proposed, which is configured to (at least partially) implement a method presented here. In other words, this particularly relates to a computer program (product) comprising instructions which, when executed by a computer, cause the computer to execute a method proposed here. The computer program can be executed, in particular, on a control and regulation device of the air conditioning unit. Advantageously, the electrical power consumption of the circulation pump is already available to the control and regulation device or can be queried by a pump control device.

[0022] According to a further aspect, a machine-readable storage medium on which the computer program is stored is also proposed. The machine-readable storage medium is usually a computer-readable data carrier.

[0023] According to a further aspect, a control and regulating device for an air conditioning unit is also proposed, configured to carry out a method proposed here. For this purpose, the control and regulating device can, for example, comprise and / or have a processor. In this context, the processor can, for example, execute the method stored in a memory (of the control and regulating device). Advantageously, data for carrying out a method proposed here can also be stored in the memory of the control and regulating device, for example one or more performance limit values, or data can be stored there as part of the process implementation.

[0024] According to a further aspect, an air conditioning unit is also proposed, comprising a control and regulation device as proposed here. The heating device can be, in particular, a gas heating device. The gas heating device can have a burner and a conveying device with which a mixture of combustion gas (hydrogen) and combustion air can be supplied to the burner.

[0025] The details, features, and advantageous embodiments discussed in connection with the method can also be applied to the air conditioning unit, the control unit, and / or the computer program, and vice versa. In this respect, reference is made in full to the explanations therein for a more detailed characterization of the features.

[0026] This disclosure thus provides a method for detecting gas in a heating circuit of an air conditioning unit, a computer program, a control device, and an air conditioning unit, which at least partially solve the problems described with reference to the prior art. In particular, the method, the air conditioning unit, the computer program, and the control device at least contribute to providing a particularly simple method for detecting gas in a heating circuit. A significant advantage is the fact that no additional sensors or other installations are required to implement the method. Therefore, the method can also be easily implemented on existing systems as part of a software installation.

[0027] 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: an air conditioning unit proposed here, Fig. 2: a heating circuit, and Fig. 3: parameter curves that can occur when carrying out a method proposed here.

[0028] Fig. 1shows, by way of example and schematically, an air conditioning unit 1 proposed here, embodied here as a gas-fired heating unit. This unit may comprise a heat generator 3 and heat exchanger 12. The heat generator 3 can generate heat by combustion of a fuel gas such as natural gas or hydrogen and transfer it to the heating circuit 2 via the heat exchanger 12. The heating circuit 2 has a flow line 8 through which water heated by the heat generator 2 and heat exchanger 12 can be supplied as a heat transfer medium to consumers such as radiators or surface heating systems (underfloor heating, wall heating) and subsequently returned via a return line 9.

[0029] A circulation pump 5 can be arranged in the heating circuit 2, which can circulate the water in the heating circuit in a flow direction 13. A degassing area 6 can be arranged in the heating circuit 2, in which gas bubbles contained in the heating circuit 2 can collect. The gas collected in the degassing area 6 can escape through a valve 7 arranged at the geodetically highest point of the degassing area 6. It is pointed out that due to the schematic representation of the Fig. 1 the geodetic position of valve 7 in the Fig. 1 is not recognizable.

[0030] The air conditioning unit 1 may comprise a control and regulation device 4 that can execute a method proposed here. For this purpose, the control and regulation device 4 may be electrically connected to the heat generator 3, the circulation pump 5, the valve 7, a display device 10, and a network 11.

[0031] Fig. 2shows, as an example, heating circuit 2 with heat exchanger 12, a secondary heat exchanger 15, which can be configured for heat exchange with a mass flow of domestic water, and circulation pump 5. Due to the air contained in heating circuit 2, heat exchanger 12 has a coil 14 that is filled with air. The air-filled coil 14 therefore does not participate in the heat exchange with heat generator 3, which significantly reduces the transferable thermal output of heat generator 3. Due to the lack of heat dissipation in the area of ​​the air-filled coil 14, damage to heat exchanger 12 or neighboring components due to overheating can also occur.

[0032] Fig. 3 shows an example and schematically a parameter curve that can be achieved when implementing a method proposed here. The diagram shows the electrical power consumption Forof the circulation pump 5 at a defined test speed over the service life N of the air conditioning unit 1. As an example, a first electrical power consumption 17 and a second electrical power consumption 18 of the circulation pump 5 are shown. The first electrical power consumption 17 indicates the power consumption For the circulation pump 5 in a degassed state after a new installation of the heating circuit 2. The second electrical power consumption 18 shows the electrical power consumption For with an air-filled winding 14, also after the new installation. The first electrical power consumption 17 can be understood as the power limit 19. In addition, a tolerance 20 is shown, which is added to the power limit 19 when comparing the recorded electrical power consumption with the measured electrical power consumption or deducted from the recorded electrical power consumption. For can be deducted.

[0033] Over the service life, the power consumption decreases For of the circulation pump 5 due to contamination and calcification, which can cause an increase in the hydraulic pressure loss. This change in the electrical power consumption For over the service life N is shown in a first curve 16. According to a method proposed here, this change can be determined by regularly recording the power consumption at intervals. The determined change can be incorporated into the detection of gas in heating circuit 2 by adjusting the tolerance 20 accordingly. In particular, the change in power consumption can be added to the tolerance 20. As a result, a second curve 21 can be determined, which represents the power limit 19 minus the adjusted tolerance 20.

[0034] According to one embodiment of the method, a degassing process can be initiated upon detection of gas in heating circuit 2. For this purpose, the circulation pump 5 can be controlled at varying speeds, which promote the release of gas from the heat transfer medium due to the resulting pressure turbulence and associated negative pressures. Subsequently, the valve 7 of the degassing area 6 can be opened, allowing the gas to escape from heating circuit 2. This advantageously enables fully automated degassing.

[0035] If gas is detected in the heating circuit 2, information about this can be sent as a message via the display device 10 of the air conditioning unit 1 or via the network 11, in particular the Internet, or can be made available for retrieval, for example via an app on a mobile device, as part of the process. List of reference symbols

[0036] 1Air conditioning unit 2Heating circuit 3Heat generator 4Control unit 5Circulation pump 6Degassing area 7Valve 8Flow 9Return 10Display device 11Network 12Heat exchanger 13Flow direction 14Air-filled heat exchanger coil 15Secondary heat exchanger 16First curve 17First power consumption 18Second power consumption 19Power limit 20Tolerance 21Second curve

Claims

1. Method for detecting gas in a heating circuit (2) of an air conditioning unit (1), comprising a circulating pump (5) for circulating a liquid heat transfer medium in the heating circuit (2), wherein a power consumption of the circulating pump (5) is detected and, if a power limit value (19) is undershot, a relevant proportion of gas is concluded in the heating circuit (2), wherein the circulating pump (5) is operated at a predetermined test speed when the power consumption is detected, and / or the power limit value (19) is predetermined as a function depending on the speed of the circulating pump (5), wherein a tolerance (20) of the power consumption is included in a comparison with the power limit value (19), a change in the detected power consumption is determined by regular, time-spaced detection of the power consumption, and an adjustment of the tolerance (20) takes place on the basis of the change.

2. Method according to claim 1, wherein when the power limit value (19) is undershot, degassing of the heating circuit (2) is initiated and / or information about the undershooting of the power limit value (19) is displayed on a display device (10) and / or is made available for retrieval via a network (11) or is sent as a message.

3. Method according to one of the preceding claims, wherein the power limit value (19) is determined in advance by means of a measurement of the power consumption following a degassing process of the heating circuit (2).

4. Air conditioning unit (1), comprising a heating circuit (2), a control and regulating device (4) and a circulation pump (5) as well as means for carrying out the method according to claim 1.

5. A computer program comprising instructions which cause an air conditioning device (1) according to claim 4 to carry out the method according to claim 1.

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