Method for monitoring and / or controlling a heating system

Abstract

The invention relates to a method for monitoring and / or controlling a heating system, comprising a pipeline network with a variable system resistance and at least one heat source, which feeds a heating medium with a defined flow temperature into the pipeline network, and at least one circulation pump for circulating the heating medium within the pipeline network, with the method steps of determining the current flow and / or return temperature, determining the system resistance of the pipeline network, and calculating a correlation value between the current flow and / or return temperature and the current system resistance.

Description

[0001] Description

[0002] Method for monitoring and / or controlling a heating system

[0003] The invention relates to a method for monitoring and / or controlling a heating system, comprising a piping network with variable system resistance, at least one heat source that feeds a heating medium with a defined flow temperature into the piping network, and at least one circulating pump for circulating the heating medium within the piping network.

[0004] Living spaces or other buildings are typically heated by a central heating system. A heat source, particularly a boiler, heats the medium circulating in the piping network to a specific flow temperature. After flowing through the radiators, which are controlled by thermostatic valves, it is then pumped back to the heat source via the return line. A circulation pump provides the flow.

[0005] The target flow or return temperature of the central heating system is set by the heating control system, whereby an outside temperature-dependent setting of the flow temperature has proven to be effective in practice. The heating control system typically receives the current outside temperature via a sensor signal, which serves as an indication of the expected heat demand of the area to be heated. The heating control system receives the target specification for the flow or return temperature to be set from a stored heating curve, which specifies the corresponding target temperature for the flow or return depending on at least one operating parameter, in this case the current outside temperature. Such a heating curve is usually building-specific and can therefore be modified by the system operator in order to adjust the temperature control according to requirements. Among other things, both the steepness of the heating curve and, optionally, a possible offset can be specified.A heating curve set too flat will result in the building not receiving sufficient heat at low temperatures. In contrast, a curve set too steep will ensure the building receives sufficient heat, but will increase energy consumption unnecessarily due to boiler and piping losses.

[0006] Even with a heating curve perfectly adjusted to the current outside temperature, it is likely that unnecessary energy consumption will still occur, as the outside temperature signal does not directly correlate with heating demand. For example, heat demand is lower at low temperatures but with strong sunlight than at higher temperatures and in windy or overcast weather. Internal heat and cold sources (electrical devices such as stoves, computers, etc., as well as large crowds or open windows) can further influence demand.

[0007] In summary, the previously used heating control based on the outside temperature has the following two weaknesses:

[0008] - the heating curve is building-specific and is usually set too steep

[0009] - the heating requirement can only be derived suboptimally from the outside temperature

[0010] The object of the present invention is to provide an improved possibility for controlling the temperature of the circulating heating medium, which overcomes the above-mentioned disadvantages.

[0011] According to the invention, this object is achieved by a method according to the features of claim 1. Advantageous embodiments of the method are the subject of the dependent claims. Furthermore, the invention is also achieved by a circulation pump, heat source, and / or heating system according to the features of claims 15 to 16.

[0012] According to the invention, a method is proposed in which the current flow and / or return temperature of the heating medium circulating in the piping network is first determined. The flow temperature is understood to be the temperature that the heating medium has immediately downstream of, or at least in the vicinity of, the heat source before flowing through a heat exchanger or radiator. The return temperature is understood to be the temperature of the heating medium when it flows from the piping network back to the heat source, i.e., preferably immediately upstream of the heat source. The heat source can be of any design; for example, it can include a burner, a condensing boiler, a heat pump, etc.

[0013] In addition to temperature measurement, the system resistance of the piping network is determined according to the invention, e.g., measured or calculated or estimated based on other operating data. The system resistance of the piping network is dynamic in heating circuits with integrated fittings, such as valves, especially thermostatic valves, and consists of a static and dynamic component. The static component is determined by the pipe resistance of the piping network. The dynamic component depends on any fitting positions, especially valve positions, within the system, primarily on the degree of opening of installed valves, especially thermostatic valves of individual radiators or other heat exchangers within the system.Since the degree of opening of the valves, especially thermostatic valves, is characteristic of the current heat demand in the respective room, the current heat demand can be determined based on the system resistance, especially the dynamic component.

[0014] The inventor recognized that a certain correlation exists between the medium temperature and the system resistance. This knowledge makes it possible to determine, by monitoring both values, whether the heating system is running under optimal conditions, i.e. whether the system can meet the required heat demand without consuming unnecessary energy. According to the invention, it is therefore proposed to determine a correlation value on the basis of the determined flow and / or return temperature and the determined system resistance. This correlation value enables an assessment of the operating conditions and system efficiency. In other words, the method can be used to evaluate, for example, whether the current control of the heating system, in particular of the heat source, can cover the current heating demand without consuming unnecessary energy. This enables, for example, extensive options for system control, e.g.The method can be used in addition to an outside temperature-dependent heating control system. Ideally, it is even possible to dispense with the outside temperature as a reference variable, making the use and installation of an outside temperature sensor unnecessary.

[0015] Preferably, it can be provided that the method provides for an evaluation of the current flow and / or return temperature, for example to the effect that the currently set flow and / or return temperature is too high or too low to ensure optimally efficient heating operation.

[0016] The current flow or return temperature can be determined using sensors, i.e., by at least one integrated sensor in the corresponding pipe section. A sensor built into the circulation pump could also be used. It is also conceivable to determine the flow and / or return temperature using an estimation algorithm or to calculate it indirectly based on other operating parameters. The estimation algorithm uses, in particular, pump operating parameters, such as the current pump speed and / or the torque of the pump drive unit, and is therefore best executed on or by the circulation pump.

[0017] The current system resistance could theoretically be measured. However, it is preferred to calculate the system resistance using the flow rate Q and / or the hydraulic pressure of the heating medium within the system. The latter parameters are available, for example, from the circulation pump or the heating control system, so that the system resistance can be calculated for the current operating point. The flow rate and head of the pump can be determined using sensors, for example. However, it is also conceivable that these values ​​are also calculated based on other operating parameters of the circulation pump, such as the current power consumption and speed of the pump drive. In this case, too, the use of an estimation algorithm to determine the flow rate and head, restrictive system resistance, is conceivable.

[0018] According to a particularly preferred embodiment of the invention, the correlation value is determined by the ratio of the current flow or return temperature to the current system resistance. In this context, a continuous determination of the correlation value is sensible. However, the correlation value could alternatively be recorded only at specific time intervals or cyclically.

[0019] It makes sense to continuously monitor the correlation value, especially to detect changes over time. Temporal changes occur particularly when the energy demand of the rooms to be heated or the operating point of the heating system changes, such as night mode. Based on this temporal development of the correlation value, it can be determined whether the current flow and / or return temperature allows for efficient system operation.

[0020] As already explained in the introductory part of the description, the heat source or the internal temperature control can take into account a heating curve that specifies the target temperature of the flow and / or return flow depending on at least one parameter, in particular the outside temperature. If this is the case, an evaluation of the heating curve used can be made by evaluating the correlation value determined according to the invention.

[0021] With an optimal heating curve, the ideal flow or return temperature would always be set under all possible operating conditions, covering the current heating demand without consuming unnecessary energy. However, if the heating curve is set too steeply, i.e., the flow temperature is set too high for the current heating demand, the thermostatic valves must throttle away the excess heat input, which increases the system resistance. The ratio and thus the correlation value between flow / return temperature and system resistance changes.

[0022] With this knowledge, it is now possible to evaluate the currently used heating curve and, if necessary, adjust it to further optimize heating operation.

[0023] If, for example, a change in the correlation value or a change in the correlation value by a certain minimum amount is detected, the gradient and / or an offset value of the heating curve is assessed as too low. The evaluation result can, for example, be provided in the form of a recommendation for action for adjusting the heating curve as electronic information that can be communicated to any external device. A visual or acoustic information display of the result is also conceivable. Such an approach is sensible and conceivable, for example, if the process is carried out entirely by a circulation pump. Alternatively or in addition to the information output, the process can also provide for automatic adjustment of the heating curve in order to increase its parameters, in particular the gradient and / or offset value. If the correlation value determined over a certain period does not change or changes only slightly.If the change is only within a tolerable range and the correlation value is also greater than a definable limit, the gradient of the heating curve may be considered too high. In this case, the heating curve could be automatically adjusted to reduce the gradient.

[0024] If, however, the correlation value remains constant or lies within the tolerance range, and the magnitude of the correlation value falls below the aforementioned limit, it is assumed that the heating curve is optimally or at least sufficiently well adjusted. In this case, the heating curve is not adjusted. The above statements refer to an adjustment of the heating curve of a heating control system. However, the fundamental idea of ​​the invention of the application can also be applied to heating control systems that are not outside temperature-based or do not control the flow temperature using a stored heating curve. Under such conditions, the method can also be used effectively; in fact, the method may make recording and taking the outside temperature into account unnecessary.It is conceivable, for example, that the heating control system initially adjusts the flow and / or return temperature to a predefined setpoint. Subsequent adjustment of the flow temperature is then carried out exclusively, or at least primarily, by the determined correlation value, which enables a precise statement about the current heating demand. In this case, for example, an external sensor for detecting the building's outside temperature could be dispensed with, and instead control could be carried out exclusively on the basis of the proposed method according to the invention. However, it is also conceivable that, in addition to the method according to the invention, further parameters for setting the flow and / or return temperature are taken into account.

[0025] It is also conceivable that the method according to the invention is not used, or at least not only, during regular operation, but instead that a test procedure can be carried out during which the flow temperature is specifically manipulated in order to determine the behavior of the system, in particular the change in system resistance, based on this. This procedure enables, for example, a targeted optimization process or a learning function for setting the operating parameters of a heating control system. The method according to the invention can also be combined with any other control functions of a heating control system or superimposed on these already implemented control functions. Likewise, the type and extent of the automatic adjustment of the heating curve can be set using one or more configurable parameters. In this context, a configurable risk factor that determines the scope for change for the adjustment of the heating curve is conceivable.If a high risk factor is configured, a larger change to the heating curve, in particular to the gradient and / or the offset value, is permissible after the heating curve has been evaluated, whereas with a lower configured risk factor, only a smaller adjustment to the heating curve is permissible. Alternatively or in addition, a resident feedback function can be implemented that records feedback from the occupant of the building to be heated using appropriate input devices, in particular using operating devices on the pump and / or the heating control system and / or via an external communication device such as a smartphone or tablet with an installed application, and considers this feedback for further process execution. This allows a manual evaluation of a previously performed adjustment to the heating curve to be taken into account and included for future adjustments.

[0026] The invention also relates to a pump, in particular a centrifugal pump, having a pump control configured to carry out the method according to the invention, wherein the pump is preferably communicatively connected to a heating control of the heat source via at least one interface in order to be able to evaluate and / or adjust the heating curve. The invention also relates to a heat source, in particular a burner / boiler, having an internal heating control configured to carry out the method according to the invention, wherein the heat source is preferably communicatively connected to a circulation pump of the heating system via at least one interface in order to evaluate and / or adjust the heating curve.

[0027] The invention also encompasses a heating system having at least one pump and one heat source, wherein the pump and / or the heat source each have a controller and / or a central controller configured to carry out the method according to the invention. The method or the individual method steps can be carried out entirely by the pump controller or the heating controller. However, a distributed method embodiment is also conceivable, with sub-steps being carried out both on the pump controller and on the heating controller. Furthermore, it is also possible to provide a separate central system controller that carries out the necessary method steps entirely or at least partially, with or without the support of the pump and / or heat source.For the distributed execution of the process steps, it is naturally necessary that the individual controls, in particular the pump control and / or the heating control, can communicate with each other via suitable interfaces.

[0028] Further advantages and features of the invention will be explained in more detail below with reference to an embodiment illustrated in the drawings. They show:

[0029] Figure 1 : a diagram showing the time course of the flow temperature and the system resistance within a heating system,

[0030] Figure 2: a diagram showing the time course of the calculated correlation value and

[0031] Figure 3: a schematic representation of the flow diagram of the method according to the invention.

[0032] The method according to the invention will be explained using the example of a heating system that, for example, includes a boiler as a heat source and adjusts the flow temperature based on a heating curve. The heat transfer medium is circulated in the pipe network by a heating circulation pump, which pumps the medium through the circuit at a flow rate and a certain head depending on the operating point. The system resistance is influenced by the valve position of individual thermostatic valves on the radiators.

[0033] In the exemplary embodiment, the process is primarily carried out by the integrated pump control of the heating circulation pump. According to the core concept of the invention, the heating pump determines the actual heat demand in the heating system and provides this information to the burner's heating control system, for example, to adjust the flow temperature control. The heating control system then adjusts the flow temperature either based solely on the demand determined by the pump or combines the demand determined by the pump with the outside temperature signal.

[0034] To determine the current heat requirement, the pump has the following parameters available:

[0035] Flow temperature: The flow temperature is determined by the pump either by an external sensor or by an internal estimate.

[0036] System resistance: The system resistance describes the losses in the pipes as well as the sum of the losses of all thermostatic valves. Since the losses in the pipes are constant, the position of the thermostatic valves can be directly determined from the system resistance. The system resistance is calculated as follows: = H / Q 2

[0037] The flow rate Q and head H are typically determined by an internal estimation algorithm in the pump control system.

[0038] Of crucial importance is the correlation between the set flow temperature and the system resistance. If the heating curve were optimally adjusted, all weather influences would be compensated by the flow temperature control, and the flow temperature signal would be completely independent of the system resistance. If, on the other hand, the heating curve is set too steep, the thermostatic valves will throttle away the excess heat input, which is indicated by an increase in the system resistance.

[0039] Laboratory studies have shown that if the heating curve is set just slightly too steep, the system resistance follows the flow temperature. To illustrate this relationship, reference is made to the temporal progression of the flow temperature and the system resistance shown in Figure 1. The building under investigation switched between day and night mode, which can be seen from the sudden changes in the flow temperature. The period between 60 hours and 120 hours did not include a switch to night mode (e.g. on weekends). Figure 1 clearly shows that the system resistance signal follows the flow temperature progression. This is because when the flow temperature is high, the thermostatic valves have to close to keep the room temperature constant. Closed valves lead to an increase in the system resistance.The influence of the flow temperature on the system resistance is dominant compared to other influences such as a window being opened briefly.

[0040] Due to the high correlation between flow temperature and system resistance, an approximately constant factor between flow temperature and system resistance can be derived, which can be calculated, for example, as follows:

[0041] Correlation value = flow temperature / system resistance

[0042] Figure 2 shows an example of the resulting curve of this correlation value for the measured values ​​determined in Figure 1. Except for tolerable fluctuations, the figure shows a nearly constant curve of the correlation value. This correlation value is proportional to the amount by which the heating curve is set too steep. The heating control system can therefore deduce from the correlation value signal whether the heating curve is set too steep or too flat.

[0043] The following rules can be followed:

[0044] Case 1 : Correlation value not constant -> heating curve too flat:

[0045] If the correlation value is not constant, the thermostatic valves are not following the flow temperature. This indicates that the heating curve is too flat. The heating curve needs to be steepened.

[0046] Case 2: Constant correlation value, large correction value -> heating curve too steep: If the correction value is constant, the heating curve is not too flat and the building is adequately supplied with heat. However, if the correlation value is large, this indicates that the building is oversupplied and energy consumption is unnecessarily high. The heating curve must be set flatter.

[0047] Case 3: Correlation value constant, correction value small -> heating curve perfect:

[0048] A constant correlation value means there is no undersupply and the heating curve is not set too flat. If the correlation value is low, the heating curve is not too steep. In this case, the heating is running optimally.

[0049] Figure 3 shows the previously described control process again schematically. In block 10, the flow temperature and the system resistance are first determined. The course of the correlation value is monitored over a specific period of time, in particular continuously. If this is approximately constant, the process proceeds to block 20, which determines the level of the correlation value. If the correlation value is above a specific limit, the process continues with block 30. Here, it is determined that the heating curve must be set steeper, which the pump communicates to the heating control system via an interface. If, however, the determined correlation value is low and below the limit, the currently used heating curve is assessed as optimal and is not modified. The process returns to block 10.

[0050] However, if block 10 detects that the correlation value is not constant, the process proceeds to block 40. In this case, a message is sent to the heating control system, indicating that the heating curve must be set steeper to cover the heat demand in the building.

Claims

Patent claims Method for monitoring and / or controlling a heating system. Method for monitoring and / or controlling a heating system, comprising a pipe network with dynamically variable system resistance, at least one heat source that feeds a heating medium with a defined flow temperature into the pipe network, and at least one circulation pump for circulating the heating medium within the pipe network, comprising the following process steps: Determining the current flow and / or return temperature, Determining the current system resistance of the piping network, calculating a correlation value between the current flow and / or return temperature and the current system resistance. A method according to claim 1, characterized in that the calculated correlation value is used to evaluate the flow and / or return temperature and / or to adjust a setpoint for the flow and / or return temperature. A method according to any of the preceding claims, characterized in that the flow temperature is determined by means of a sensor and / or by estimation, in particular by estimation from the pump. A method according to any of the preceding claims, characterized in that the system resistance includes the losses in the piping of the heating system and losses of the thermostatic valves of one or more radiators in the heating system. A method according to any one of the preceding claims, characterized in that the system resistance is determined based on the measured flow rate and the resulting delivery head of the circulation pump. A method according to claim 5, characterized in that the flow rate and / or the delivery head are determined by sensors and / or by an estimation algorithm, in particular by the circulation pump. A method according to any one of the preceding claims, characterized in that the correlation value is determined by the ratio of the supply temperature to the system resistance. A method according to any one of the preceding claims, characterized in that a change in the correlation value over time is monitored.A method according to any of the preceding claims, characterized in that the flow temperature controlled by the heat source is set taking into account a heating curve which defines a flow temperature as a function of at least one parameter, in particular the outside temperature, and in which an evaluation and / or adjustment of the heating curve is carried out taking into account the correlation value. A method according to claim 9, characterized in that, in the event of a detected change in the correlation value, in particular a change by at least a certain amount, an adjustment of the heating curve is recommended and / or carried out, in particular an adjustment of the slope of the heating curve and / or an offset value of the heating curve is recommended and / or carried out.Method according to one of claims 9 or 10, characterized in that the slope of the heating curve is reduced if the correlation value remains constant or varies only within a tolerance band and the correlation value exceeds a definable limit value. A method according to any one of claims 9 to 11, characterized in that the heating curve is not adjusted and / or the heating curve is evaluated as optimal if the correlation value is constant or varies only within a tolerance band and does not exceed a defined limit value. A method according to any one of the preceding claims 1 to 8, characterized in that the heat source initially regulates the flow temperature to a predetermined value and any subsequent adjustment of the flow temperature is carried out exclusively or primarily taking into account the correlation value. A method according to any one of the preceding claims, characterized in that the method is implemented on a circulation pump of the heating system and / or by the heating control of the heat source, wherein the circulation pump and heat source are preferably connected via a communication interface for the exchange of one or more parameters.A method according to any one of the preceding claims, characterized in that the method performs a test procedure repeatedly or on demand, during which the flow temperature is selectively manipulated. A pump, in particular a heating circulation pump, with a pump controller configured to perform the method according to any one of the preceding claims, wherein the pump preferably communicates with a heating control unit of the heat source via at least one interface in order to evaluate and / or adjust the heating curve. A heat source, in particular a boiler, with an internal controller configured to perform the method according to any one of the preceding claims, wherein the heat source preferably communicates with a circulation pump via at least one interface in order to evaluate and / or adjust the heating curve. Heating system comprising at least one pump and one heat source, wherein a pump control of the pump and / or a heating control of the heat source are configured to carry out the method according to any one of claims 1 to 15.

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