METHOD FOR ADJUSTING A FEED OUTPUT IN A HEATING CIRCUIT

Description

[0001] The invention relates to a method for adjusting a delivery rate in a heating circuit, a computer program, a machine-readable storage medium, and a device with a Heating unit for a building.

[0002] The heating circuit in question comprises a heating appliance, a pump, and at least one radiator. To regulate the flow through this radiator, a pressure-independent control valve is installed in the circuit, activated once a defined valve pre-charge pressure is reached. Such control valves typically require a relatively high pre-charge pressure, which is particularly energy-intensive. Therefore, even qualified technicians usually simply set the heating circuit pump to its highest setting in such a circuit, as the maximum required pre-charge pressure (for the entire heating circuit) cannot be determined without sophisticated, additional measuring equipment that is not typically available during the commissioning of a heating system.Setting the pump to its highest pressure is intended to ensure that the pre-charge pressure at each control valve (regardless of its distance from the heating circuit pump) is sufficiently high to guarantee stable operation of the control valves. However, this approach is particularly inefficient from an energy perspective.

[0003] DE 10 2011 008165 A1 discloses a method for the performance-optimized operation of an electrically driven pump at low volume flows. CH 705 143 A1 discloses a method for balancing a group of consumers in a fluid transport system. DE 10 2017 203474 A1 discloses a method for controlling a variable-speed circulating pump.

[0004] It is therefore an object of the invention to provide a method that at least partially solves the problems described in connection with the prior art. In particular, it should enable improved operation of a heating circuit from an energy and / or acoustic point of view.

[0005] This problem is solved according to a method with the features of claim 1. Advantageous embodiments result from the features of the dependent claims.

[0006] This involves a method for adjusting the flow rate in a heating circuit with a heating appliance, a pumping device, and at least one flow-through radiator, wherein, to regulate the flow through the at least one radiator, a pressure-independent control valve is arranged in the area of ​​the at least one radiator in the heating circuit once a defined valve pre-pressure has been reached. The method comprises at least the following steps: a) Determining a design point for the flow rate through the heating circuit, b) Approaching the design point by increasing or decreasing the delivery rate of the pumping device until the design point is reached, c) Determining a measure for a minimum delivery rate for the heating circuit, depending on a measure for the delivery rate at which the design point is reached in step b), so that even in the most unfavorable flow path through the heating circuit, the required valve pre-pressure is present during regular operation to enable the correct function of the control valve.

[0007] This procedure can be carried out, for example, during the initial commissioning and / or maintenance of a heating system. The procedure can advantageously contribute to an energy-efficient adjustment of the pumping device, such as a circulation pump in a heating system using pressure-independent control valves. Using this procedure, the pumping device, in particular the (heating circuit or circulation) pump (or its delivery head), is adjusted to the minimum required (system) pressure. This ensures that even in the most unfavorable flow path through the heating circuit (usually at the radiator furthest from the pumping device), the required valve pre-pressure is always present during regular operation to enable the correct function of the control valve. This measure can help achieve the most energy-efficient operating point possible.

[0008] The heating circuit is generally a closed loop. It can comprise multiple pipes that connect the heating appliance and / or the circulation pump to at least one radiator. A heat transfer medium, such as water, can circulate within the heating circuit. The circulation pump can be, for example, a pump, such as a heating circuit pump and / or a circulation pump. The circulation pump can also include multiple pumps. The circulation pump can be located within the heating appliance and / or connected to it. The heating circuit can be located in a (residential) building and / or serve to heat a building, in particular at least one room within the building. The heating circuit can include multiple radiators, especially those connected in parallel. The radiators can be of different designs, in particular different sizes.

[0009] The heating appliance in question is typically a heating unit for a (residential) building. It can be a gas and / or oil-fired heating appliance. In other words, this refers specifically to a heating appliance designed to burn one or more fossil fuels, such as liquefied petroleum gas (LPG), natural gas, and / or heating oil, possibly with the addition of ambient air, to generate energy for heating, for example, water for use in an apartment or at least part of an apartment or house. For instance, the heating appliance could be a so-called condensing gas boiler. The heating appliance typically has at least one burner and a (secondary) delivery system, such as a fan, which delivers a mixture of fuel (gas) and combustion air (through a mixing channel in the heating appliance) to the burner.The exhaust gas produced by combustion can then be routed through an (internal) exhaust pipe of the heating appliance to the building's exhaust system. Alternatively, the heating appliance can include a heat exchanger of a heat pump system. In this case, the heating appliance can be configured to transfer heat between a refrigeration circuit and the heating circuit. The building can be either a residential building and / or a commercial building.

[0010] Each radiator is typically equipped with a (dynamic) control valve (either assigned to or / or installed upstream of the radiator). Once a predefined (or adjustable) valve pressure is reached, this valve regulates the flow rate through the radiator independently of the system pressure (or the total pressure of the heating circuit). These control valves are commonly referred to as "pressure-independent control valves." The pressure-independent control valve can be adjusted (manually and / or with the appropriate tool) to different pre-pressure levels. These levels allow for stepless adjustment of the (maximum) flow rate through the radiator. The (maximum) flow rate through the radiator can be selected based on factors such as the size and / or location of the room being heated and / or the size of the radiator itself. Setting the required maximum flow rate...The volume flow through the radiator can be adjusted directly at the control valve and contribute to the hydraulic balancing of the heating circuit.

[0011] A thermostat can be attached to the control valve, allowing for manual temperature setting. The thermostat can actuate the control valve, influencing the flow rate through the radiator based on at least the current room temperature and the manually set room temperature. Specifically, the flow rate through the radiator can be throttled from the adjustable (maximum) flow rate to a set value on the control valve. Alternatively or additionally, a radiator sensor can be used in conjunction with the control valve. Such control valves offer the advantage of maintaining a constant flow rate above a certain pre-charge pressure.This can help to at least reduce acoustic emissions from the heating circuit.

[0012] In step a), a design point for the flow rate through the heating circuit is determined (in particular, calculated). The design point can be, for example, a specific total volumetric flow rate or total mass flow rate through the heating circuit. If several radiators are connected in parallel in the heating circuit, the total volumetric flow rate can be determined, for example, by summing the individual radiator volumetric flow rates. A safety margin can also be added. The individual radiator volumetric flow rates refer specifically to the maximum volumetric flow rate through the respective radiator. The maximum volumetric flow rate through the radiator can depend, for example, on the size and / or location of the room to be heated and / or on the size of the respective radiator. The maximum volumetric flow rate through the radiator can be selected and / or set at the control valve (associated with the respective radiator).The design point can generally be determined manually and / or in a heating appliance control system.

[0013] In step b), the design point is approached by increasing or decreasing the delivery rate of the conveying device until the design point is reached. The design point can be approached, for example, from a standstill of the conveying device by (continuously) increasing the delivery rate (in particular by increasing the speed of the conveying device). Alternatively, the design point can be approached (alternatively or possibly additionally before and / or after) from a maximum speed of the conveying device by (continuously) decreasing the delivery rate (in particular by decreasing the speed of the conveying device). Approaching the design point can generally be controlled manually and / or by a heating device controller. During the approach to the design point, the flow rate can be adjusted.The (total) volume flow through the heating circuit can be monitored, for example, by means of a display on the heating device by an operator and / or by a heating device control unit.

[0014] The approach to the design point by increasing or decreasing the delivery rate of the pumping device can continue until the point is (sufficiently reliably) detected. Reaching the design point can be (sufficiently reliably) detected, for example, by the fact that the flow rate or (total) volume flow through the heating circuit no longer changes (i.e., remains at the value of the design point), even though the delivery rate (especially the speed of the pumping device) continues to increase or decrease. This can be explained, in particular, by the fact that once the design point is reached, the control valves limit the volume flow through the heating circuit. A further increase in the delivery rate would therefore primarily result in power loss. This method aims to reduce or, if possible, avoid this power loss.

[0015] In step c), a measure for the minimum flow rate for the heating circuit is determined, depending on a measure for the flow rate at which the design point in step b) is reached. The measure for the flow rate at which the design point in step b) is reached could, for example, be the rotational speed of the pumping device, in particular the rotational speed of a pump at which the design point in step b) has been (sufficiently reliably) reached.The measure for the minimum delivery rate can, for example, be the minimum rotational speed of the conveying device at which the conveying device generates the minimum required (system) pressure, so that, according to the invention, even in the most unfavorable flow path through the heating circuit (generally at the radiator furthest from the conveying device), the required valve pre-pressure is (always and / or just barely) present during regular operation to enable the correct function of the control valve. The measure for the minimum delivery rate can, for example, be determined (depending on the measure for the delivery rate at which the design point in step b) is reached) by setting the value for the measure for the minimum delivery rate to the value of the measure for the delivery rate at which the design point in step b) is reached (possibly with a safety margin).

[0016] In an advantageous embodiment, it is proposed that the design point describes a specific volume flow rate through the heating circuit. Furthermore, it can be provided that the design point describes the (maximum possible) total volume flow rate through the heating circuit. In the case of radiators connected in parallel, the total volume flow rate can, for example, be determined from the sum of the individual (maximum possible) radiator volume flow rates (which are adjustable via the control valves). In addition, a safety margin can be included.

[0017] In a further advantageous embodiment, it is proposed that the speed of the conveying device be increased or decreased to reach the design point. In this context, for example, the speed of a conveying pump or circulation pump of the heating circuit can be increased or decreased.

[0018] In a further advantageous embodiment, it is proposed that, to determine the measure for the minimum conveying capacity, a minimum rotational speed of the conveying device at which the design point is reached is determined and multiplied by a safety factor. The safety factor can, for example, be in the range of 5% to 20%, particularly in the range of 5% to 15% or at approximately 10%.

[0019] According to a further advantageous embodiment, it is proposed that a hydraulic balancing of the heating circuit be carried out before step a). In this context, the (step-by-step) adjustability of the control valves can be used particularly advantageously to adjust the flow rate through individual (parallel) branches of the heating circuit. Throttles can also be integrated into the heating circuit in a generally known manner, for example, to promote the flow through more distant branches.

[0020] In a further advantageous embodiment, it is proposed that, at least during step b), no radiator sensor and / or thermostatic head is connected in the area of ​​the radiator. Thus, during step b), the maximum flow rate, selectable or adjustable (in stages) via the control valve, can flow through the respective radiator. Particularly during initial commissioning of the heating circuit, the installation of radiator sensors and / or thermostatic heads can be omitted before and during step b). Especially during maintenance, all installed radiator sensors and / or thermostatic heads can be removed before step b).

[0021] In a further advantageous embodiment, it is proposed that the minimum delivery rate determined in step c) be stored in a heating appliance control unit. For example, a minimum speed of the delivery device for regular operation of the heating circuit can thus be stored and / or set in the heating appliance control unit.

[0022] According to another aspect, a computer program according to claim 9 is also proposed.

[0023] According to another aspect, a machine-readable storage medium according to claim 10 is also proposed.

[0024] Another aspect is also proposed: a device according to claim 8.

[0025] The invention will now be explained in detail using the figures.

[0026] They represent: Figure 1: an exemplary flow chart for the procedure described herein, and Figure 2: an exemplary and schematic representation of a building with a device set up for carrying out a procedure described herein.

[0027] Figure 1 shows an exemplary flowchart for the procedure described here for adjusting the flow rate in a heating circuit 1 (see also Fig. 2 ) with a heating device 2, a conveying device 3 and at least one flow-through radiator 4. In heating circuit 1, a pressure-independent control valve 5 is arranged in the area of ​​the at least one radiator 4 in heating circuit 1 to regulate the flow through it once a defined valve pre-pressure has been reached. The sequence of steps a), b) and c) indicated by blocks 110, 120 and 130 can thus be executed at least once during the process.

[0028] In block 110, according to step a), a design point for the flow rate through heating circuit 1 is determined. In block 120, according to step b), the design point is approached by increasing or decreasing the delivery rate of the pumping device 3 until the design point is reached. In block 130, according to step c), a measure for a minimum delivery rate for heating circuit 1 is determined, depending on a measure for the delivery rate at which the design point in step b) is reached.

[0029] The design point can describe a specific volume flow rate through the heating circuit 1. To reach the design point, the speed of the pump 3 can be increased or decreased. To determine the minimum flow rate, a minimum speed of the pump 3 at which the design point is reached can be determined and increased by a safety factor. Before step a), a hydraulic balancing of the heating circuit (1) can be performed. At least during step b), no radiator sensor and / or thermostatic head should be connected in the area of ​​the radiator 4. The minimum flow rate determined in step c) can be stored in a heating appliance controller 6.

[0030] Figure 2Figure 7 shows a building 7 with a heating unit 2 as an example and schematically. A heating circuit 1 is integrated into the building 7. Heating circuit 1 comprises a heating unit 2, a circulation pump 3, and, for example, two flow-through radiators 4 connected in parallel. To regulate the flow rates through the two radiators 4 independently, a pressure-independent control valve 5 is arranged in the area of ​​each radiator 4 within heating circuit 1. This control valve 5 operates independently of the heating unit 4 once a defined valve pre-pressure is reached. The circulation pump 3 is, for example, a circulating pump. The heating unit 2 is, for example, a gas-fired heating system.

[0031] The control valves 5 have the particular advantage that the flow rate in each radiator 4 can be very precisely and, in particular, constantly adjusted, which is also beneficial for minimizing noise in the heating circuit 1. However, a disadvantage of using these valves is that they require a certain pre-charge pressure to regulate the flow rate constantly. Generally, this requires an additional pressure drop of more than 80 mbar, which must be provided by the pump 3. Since the (actual) pre-charge pressure of the valve is usually unknown, the pump speed must be set sufficiently high, which is why, according to current technology, it is typically set to its maximum value. This manual over-setting results in a partially unnecessary increase in pump power and thus also an increase in electricity consumption.

[0032] The method described above can be used to set a minimum required, energy-efficient delivery rate, in particular a minimum required rotational speed of the conveying device 3 in the heating circuit 1. According to the invention, this is done with the aim of operating the heating circuit 1 at the minimum required (system) pressure, at which the required valve pre-pressure is always (and / or just barely) present during regular operation, even in the most unfavorable flow path through the heating circuit (generally at the radiator furthest from the conveying device; here the upper radiator 4), in order to enable the correct function of the control valve 5.

[0033] This can be achieved, for example, as follows: First, the required total flow rate can be calculated. Then, if necessary, all thermostatic radiator valves (TRVs) can be removed. Next, the pump speed can be increased until the required total flow rate is reached. The resulting pump speed can then be increased by a specific percentage to ensure maximum stability. This speed can be set as the minimum speed. The minimum speed can, for example, be stored as the minimum pump speed. This approach can advantageously result in minimal flow noise, a minimal pump speed, and / or minimal electrical energy consumption.

[0034] This presents a method by which the problems described in connection with the state of the art can be at least partially solved. In particular, it can enable improved operation of a heating circuit from an energy and / or acoustic point of view. Reference symbol list

[0035] 1 Heating circuit 2 Heating unit 3 Conveyor 4 Radiator 5 Control valve 6 Heating unit control 7 Building

Claims

1. Method for adjusting the flow rate in a heating circuit (1) with a heating appliance (2), a flow device (3) and at least one heat-transfer element (4) through which flow can pass, wherein, in order to regulate the flow through the at least one heating element (4), a pressure-independent control valve (5) is arranged in the area of the at least one heating element (4) in the heating circuit (1) as soon as a defined valve inlet pressure is reached, characterised by at least the following steps: a) determining a design point for the flow through the heating circuit (1), b) approaching the design point by increasing or decreasing the delivery rate of the delivery device (3) until the design point is reached, c) Determining a measure for a minimum delivery rate for the heating circuit (1), depending on a measure for the delivery rate at which the design point in step b) is reached; whereby the delivery device (3) is set to the minimum required pressure so that even in the most unfavourable flow path through the heating circuit (1) during regular operation, the required valve inlet pressure is present to enable the correct functioning of the control valve (5).

2. Method according to claim 1, wherein the design point describes a specific volume flow through the heating circuit (1).

3. Method according to claim 1 or 2, wherein the speed of the conveyor (3) is increased or decreased in order to reach the design point.

4. Method according to one of the preceding claims, wherein, in order to determine the measure for the minimum conveying capacity, a minimum rotational speed of the conveyor (3) at which the design point is reached is determined and a safety factor is applied.

5. Method according to one of the preceding claims, wherein a hydraulic balancing of the heating circuit (1) is carried out before step a).

6. Method according to one of the preceding claims, wherein at least during step b) no radiator sensor and / or thermostatic head is connected in the area of the radiator (4).

7. Method according to one of the preceding claims, wherein the minimum delivery rate determined in step c) is stored in a heating device control (6).

8. Device comprising a heating appliance (2) for a building (7), a delivery device (3), at least one radiator (4), wherein, in order to regulate the flow through the at least one radiator (4), a pressure-independent control valve (5) is arranged in the area of the at least one radiator (4) in each case when a defined valve inlet pressure is reached, designed to carry out a method according to one of claims 1 to 7.

9. Computer program comprising instructions that cause a device according to claim 8 to perform a method according to one of claims 1 to 7.

10. Machine-readable storage medium on which the computer program according to claim 9 is stored.