EP3508730B1 - Method for adjusting a pressurisation system - Google Patents

Description

The invention relates to a method for setting a proportional pressure control curve in the control electronics of a pressure boosting system for supplying a hydraulic network in a building with a number of tapping points. The invention also relates to a pressure boosting system for carrying out the method.

Pressure boosting systems are pumping stations with one or more parallel pump units and are mainly used in the drinking water supply. They increase the pressure of the drinking water provided by a supplier and thus convey it via a pipe system to all extraction points, such as taps, toilets or showers. It must be ensured that there is always sufficient pressure at each extraction point so that the drinking water flows out of the extraction point. However, the actual pressure at the consumer is usually not known, so that the pumping station is always selected so oversized and set excessively high that even in the case of unfavorable system conditions, for example extraction points that are open at the same time, the extraction point with the poorest supply is always adequately supplied.

It is known in pressure boosting systems to regulate to a constant, predetermined outlet pressure, which is kept constant regardless of the volume flow through the pumping station even if there are fluctuations in the supply pressure. This is known as the pc control ( p _nom = constant). However, such a constant-pressure regulation leads to operation that is not optimal in terms of energy, since the pressure losses increase with the volume flow ( p _v ~ Q ). Depending on the flow rate Q, a different amount of flow pressure p _FL is available for use at an extraction point. Around To avoid this disadvantage, it is also known to use a proportional pressure curve, along which the pressure booster system _is regulated, so that there is a setpoint pressure curve p set = f ( Q ) at the outlet of the pressure booster system, ie a so-called pv control. Such a proportional pressure control curve is also more convenient for the user because it leads to lower pressure fluctuations at the tapping points.

For a suitable and energy-optimal setting of a p-v control curve on the pressure boosting system, knowledge of the pressure losses pv in the hydraulic network is required, in particular at least those pressure losses that occur from the pressure boosting system via the pipe network to the hydraulically most unfavorable extraction point. These are described by the so-called system curve, also called building characteristic or system characteristic. However, the actual pressure losses are usually not known, especially not in the case that a new pressure boosting system is installed in an existing building. Optimal adjustment of the pressure boosting system is difficult here.

Methods are known for determining a system curve. However, these methods are complex, sometimes require knowledge of the structure of the hydraulic network, calculations or evaluation of measured values and can therefore usually only be carried out by specialist personnel. The pressure losses are often estimated, which involves a high degree of uncertainty about the correct setting of the pressure boosting system.

The pamphlet EP 2 915 926 A2 the applicant discloses, for example, a method for determining the system characteristic of a distribution network, with a system characteristic raised by adding a desired flow pressure being determined and set as a control characteristic for a pump.

It is therefore the object of the present invention to provide a simple method for setting a proportional pressure control curve in the control electronics of a pressure booster system that can be carried out quickly and even by untrained people and leads to a user-friendly setting of the pressure booster system.

This object is achieved by a method having the features of claim 1. Advantageous developments are specified in the dependent claims.

• einen Volumenstromwert (Q_100%) eines gewünschten Maximalvolumenstroms auf der Druckregelkurve,
• einen Höhenwert (H_geo) einer geodätischen Höhe und
• einen Fließdruckwert (p_FL) eines gewünschten Fließdrucks an der ungünstigsten Entnahmestelle umfassen,
  einen Minimaldruck (p_Q=0) bei Volumenstrom null und einen Maximaldruck (p_Q100%) bei dem Maximalvolumenstrom ermittelt, wobei die Druckregelkurve durch eine Verbindungslinie zwischen dem Minimaldruck (po=o) und dem Maximaldruck (p_Q100%) gebildet ist und von der Regelungselektronik eingestellt wird.

According to the invention, a method for setting a proportional pressure control curve in the control electronics of a pressure boosting system for supplying a hydraulic network in a building with a number of tapping points is proposed, in which the control electronics already consists of three system values, which

• a volume flow value (Q _100% ) of a desired maximum volume flow on the pressure control curve,
• an elevation value (H _geo ) of geodetic elevation and
• include a flow pressure value (p _FL ) of a desired flow pressure at the most unfavorable extraction point,
  a minimum pressure (p _Q=0 ) at zero flow rate and a maximum pressure (p _Q100% ) at the maximum flow rate is determined, with the pressure control curve being formed by a connecting line between the minimum pressure (po=o) and the maximum pressure (p _Q100% ) and of of the control electronics is set.

This procedure enables a suitable pressure regulation curve to be set on the booster system without the user having to have any knowledge of the pressure losses in the hydraulic network. Three system values are sufficient for the setting. These are easy to determine here, making the process particularly user-friendly.

The first system value, the maximum volume flow, is the target flow rate that should be present at the highest point in the building when water is drawn off.

Within the meaning of the invention, a building is understood to mean a structure that includes one or more covered rooms, can be entered and is used for the accommodation of people, animals or for the storage of things. The rooms do not necessarily have to be closed on all sides. The building can have any number of floors and extend in height or in depth. The building can also be used for private, public or industrial purposes. The building can, for example, but not exclusively, be a residential building, an apartment building, an office building, a high-rise building, a public facility such as a school, library, hospital, gym, etc. The building can also be part of a building complex, such as at an airport or exhibition center.

The hydraulic network can extend horizontally and/or vertically. It can extend throughout the building or just part of the building. In the latter case, for example, tapping points are not located in all rooms, but only in some rooms. Furthermore, in the case of a multi-storey building, the hydraulic network can only extend over some of the floors, i.e. not over all floors. In addition, the hydraulic network can also extend over two or more buildings, as is the case, for example, in residential complexes comprising several houses, or in terraced houses.

The most unfavorable extraction point can be considered to be that extraction point in the network up to which a pumped medium experiences the greatest pressure losses when viewed from the pressure boosting system. For example, the most unfavorable extraction point can be the extraction point that is highest in the building or furthest away from the pressure booster system.

The volume flow value (Q _100% ) preferably forms a default value specified at the factory, which the electronic control system expects to be confirmed or changed. The volume flow value therefore does not have to be freely specified by the user. Rather, the control electronics for its part proposes the volume flow value, which is formed by the default value specified and stored at the factory. The user can accept or change this default value and thus specify it accordingly. This means that the user does not need to know anything about the pressure boosting system or the hydraulic network for the first system value.

The change in the default value for the volume flow value can advantageously be limited to a specific change range by the control electronics in order to prevent the user from setting an unreasonable value as a result of the change.

The default value suitably corresponds to the volume flow at maximum hydraulic power of the pressure booster system. The default value is therefore on the maximum pump curve in relation to the characteristics of the pressure booster system in the HQ diagram. This ensures that the full capacity of the pressure booster system can be utilized along the pressure control curve.

As an alternative or in addition to the default value, it can be provided that the user freely predefines the volume flow value. The volume flow value (Q _100% ) can thus form an input value that can be specified by a user and whose input the electronic control system expects. This enables the pressure booster system to be customized according to the user's wishes. The default value can also be displayed to the user as a suggestion or reference value by the control electronics.

The second asset value is the geodetic height. In the context of the present invention, the geodetic height relates to the difference in height between the pressure boosting system and the highest extraction point.

The height value (H _geo ) preferably forms an input value that is to be specified directly by a user and whose input the electronic control system expects. This height value is a variable that can be easily determined on the building.

Alternatively, it can be provided that the height value (H _geo ) is determined from another piece of information that a user indicates to the control electronics. Various design variants are possible here.

For example, the height value can be determined from a building height specified by the user, which the electronic control system expects to be input. This then calculates the height value, for example based on the assumption that the pressure boosting system is set up in the basement and the highest tapping point is on the top floor. In the simplest case, the building height as Height value can be assumed for the geodetic height, since the amount by which the building height has to be increased due to the installation of the pressure booster system in the basement corresponds approximately to the amount by which the building height has to be reduced due to the position of the highest tapping point on the upper floor. Provision can preferably be made for the user to be able to change the ascertained height value manually.

Alternatively, the height value (H _geo ) can be determined from a number of floors specified by the user. For this purpose, a fixed floor height such as 3 m can be calculated in the control electronics for each floor. In order to improve the accuracy of the determination of the height value, the floor height can also be specified, which the electronic control system expects to be entered. The height value is determined from the number of floors and the floor height.

The pressure value (p _FL ) can preferably form a default value specified at the factory, the confirmation or change of which the electronic control system expects. This pressure value can be between 1 bar and 3 bar, for example. The pressure value therefore does not have to be freely specified by the user. Rather, the control electronics for its part proposes the pressure value that is formed by the default value specified and stored at the factory. The user can accept or change this default value and thus specify it accordingly. Thus, even with the third system value, the user does not need any knowledge of the pressure boosting system or knowledge of the hydraulic network.

The change in the default value for the pressure value can advantageously be limited to a specific change range by the control electronics in order to prevent the user from setting an unreasonable value as a result of the change.

As an alternative or in addition to the default value, it can be provided that the user freely specifies the pressure value. In this way, the pressure value can form an input value that can be specified by a user and whose input the electronic control system expects. This allows an individual adjustment of the booster system according to the wish of the user. The default value can also be displayed to the user as a suggestion or reference value by the control electronics.

In one embodiment variant, a geodetic pressure value (p _geo ) is calculated from the altitude value (H _geo ) or the altitude value is converted into the pressure value. The minimum pressure (po=o) is then formed from the sum of this geodetic pressure unit (p _geo ) and the flow pressure value (p _FL ). The minimum pressure forms the lowest point of the pressure control curve to be set, which is therefore fixed.

In one embodiment, a maximum pressure loss (Δp _loss,max ) is calculated from the volume flow value (Q _100% ) using a trend function (T1-T5), and the maximum pressure (p _Q100% ) from the sum of the minimum pressure (po=o) and the Maximum pressure loss (Δp _loss,max ) formed. The maximum pressure forms the highest point of the pressure control curve to be set, which is therefore also fixed. As a result, the entire pressure control curve is fixed and can be set by the control electronics.

A trend function within the meaning of the present invention describes the dependency of the maximum pressure loss (Δp _loss,max ) on the volume flow (Q) according to a square root function. Such a trend function can be determined empirically, for example using a standard-compliant pipe dimensioning and the pressure loss calculation according to generally known literature for a hydraulic network, using which the system characteristic can be determined. A specific trend function can thus be assigned to each pipe dimension. If the pipe dimensioning corresponds to a specific design standard, a specific trend function can thus also be assigned to this specific design standard.

Due to the fact that the design standards are valid at different times, there is advantageously a connection between the design standard used and the age of the building. This means that a certain trend function can also be assigned or is assigned to the age of a building.

The trend functions for different pipe dimensions or different design standards only differ in terms of their gradient, which can be described by a factor. Based on this knowledge, the trend function can advantageously describe the dependency of the maximum pressure loss (Δp _loss,max ) on the volume flow (Q) according to a root function, the slope of which is defined by a selectable design factor (k _A ). The design factor thus determines the slope of the trend function, so that only a single trend function needs to be stored in the control electronics. This can be done as a table of values or as a function.

By default, a predefined mean value of the design factor (k _A ) can be used to determine the trend function and calculate the maximum pressure drop.

However, greater accuracy can be achieved by adapting the trend function or its slope to the hydraulic network in the building using the design factor. The fact that the age of the building correlates with a specific design standard and consequently with a specific trend function can advantageously be used for this purpose. A design factor (k _A ) can be assigned to each building age, which causes a corresponding adjustment of a stored reference trend function (trend function for k _A =1) to the building.

In the method according to the invention, it can preferably be provided that the electronic control system expects the specification of the age of the building and then selects the design factor (k _A ) from a number of stored design factors based on the building age entered by the user. The corresponding trend function, whose slope is defined by the selected design factor (k _A ), is then used to calculate the maximum pressure loss.

The age of the building is also a variable that is easy to determine, for which the user has neither technical knowledge of the characteristic curve of the pressure boosting system nor knowledge of the building's hydraulic network needed. In this way, a proportional pressure control curve that is energetically good for the building or the hydraulic network can be set in the pressure boosting system in a simple manner and with few input variables, with the control electronics of the pressure boosting system doing this itself.

The invention also relates to a pressure boosting system for supplying a hydraulic network in a building with a number of tapping points, comprising at least one pump unit and control electronics that regulate it, the control electronics being set up to carry out the method according to the invention.

The method according to the invention can, for example, be stored in the control electronics in the form of a software-based setting assistant, which thus facilitates the setting of the pressure control curve on the pressure boosting system.

Further features and advantages of the method according to the invention are described below using an exemplary embodiment and the attached figures.

Fig. 1:

HQ einer Druckerhöhungsanlage mit optimaler Druckregelkurve

Fig. 2:

erweitertes HQ Diagramm

Fig. 3:

HQ-Diagramm mit Trendfunktionen

Show it:

Figure 1:

HQ of a pressure booster system with optimal pressure control curve

Figure 2:

extended HQ chart

Figure 3:

HQ chart with trend functions

• ein Volumenstromwert Q_100% eines gewünschten Maximalvolumenstroms auf der Druckregelkurve 1,
• einen Höhenwert H_geo einer geodätischen Höhe und
• einen Fließdruckwert p_FL eines gewünschten Fließdrucks an der ungünstigsten Entnahmestelle.

1 shows an HQ diagram with two maximum pump curves 2, 3 for a pressure boosting system with, for example, two pump units that can be operated in parallel. The outer maximum pump curve 3 occurs when both pump units are operated together at maximum speed. The nominal point of the pressure booster system H _set , Qset lies on the outer pump curve 3. An optimally regulated pressure booster system has a proportional pressure control curve 1 that runs through this nominal point H _set , Qset and the head difference H _set -H _Q=0 along the control curve 1 is straight maximum occurring pressure loss Δp _loss,max . To find and set this control curve 1, the According to the invention, three system values are specified for the control electronics of the pressure boosting system:

• a volume flow value Q _100% of a desired maximum volume flow on the pressure control curve 1,
• a height value H _geo a geodetic height and
• a flow pressure value p _FL of a desired flow pressure at the most unfavorable extraction point.

The maximum flow rate is the maximum flow rate on the pressure control curve. In practice, the volume flow can go beyond this, the pressure control curve then goes into a plateau, with a constant pressure being specified and the maximum pump curve forming the limit.

Since the pressure boosting system knows itself, or the manufacturer of the pressure boosting system knows about its pump characteristics, the volume flow value Q _100% can be specified by the manufacturer at the factory as the volume flow value that corresponds to the volume flow Q _set at the nominal operating point. The user then only needs to confirm this suggested default value on the control electronics. For example, the maximum volume flow is Q _100% = 8.3 m ³ /h.

The flow pressure is the static overpressure of a flowing medium that must be present at the most unfavorable tapping point during a tapping process so that the required amount of water can flow out. A default value can also be used for the flow pressure, which is suggested to the user, since at least 1 bar, preferably 2 bar, flow pressure p _FL should normally be present at a withdrawal point in order to obtain an appropriate flow rate. Here, too, the user only needs to confirm this suggested default value on the control electronics.

Thus, the user only has to enter the geodetic height value. The geodetic height here corresponds to the difference in height between the pressure boosting system and the highest extraction point and can can thus be easily determined by the user. For example, the geodetic height is 24m.

From the three system values, the control electronics determine a minimum pressure po=0 at zero volumetric flow and a maximum pressure p _Q100% at the specified maximum volumetric flow Q _100% , which in 2 are drawn. The minimum pressure po=o results from a pure conversion of the geodetic height value H _geo into a pressure value and addition of the flow pressure value p _FL With the numerical values given as an example, a minimum pressure po=o of 4.35 bar (H _geo / 10.21 + p _FL ). The maximum pressure p _Q100% results from a pure conversion of the geodetic height value H _geo into a pressure value, addition of the flow pressure value p _FL and addition of a maximum pressure loss Δp _loss,max . With the numerical values given as an example, this results in a maximum pressure p _Q100% of 5.15 bar (H _geo / 10.21 + p _FL + Δp _loss,max ).

The pressure control curve 1 to be determined is formed by a connecting line between the minimum pressure po=0 and the maximum pressure p _Q100% and is set by the control electronics after it has been determined.

The calculation of the maximum pressure loss Δp _loss,max is illustrated using FIG. This shows five trend functions T1 to T5 purely by way of example, which describe the dependency of the maximum pressure loss Δp _loss,max on the volume flow, each according to a root function. The trend functions T1 to T5 differ here only in their gradient, which is described by a design factor k _A . The gradient of the trend function depends on the hydraulic network of the building that serves the pressure boosting system, for example on the pipe diameter.

To calculate the maximum pressure drop, a representative, average trend function T3 can be used without differentiating between the individual trend functions T1 to T5, to which the design factor k _A =1 is assigned, for example. In the mean trend function T3 in FIG. 3, a maximum pressure loss Δp _loss,max of 0.8 bar results for a maximum volume flow Q _100% =8.3 m ³ /h.

The trend functions T1, T2, T4 and T5 are determined empirically based on the pipe dimensioning of hydraulic systems according to various design standards 1, 2, 3 and 4 and generally known pressure loss calculation according to literature. DIN 1988, for example, can be used as a design standard, which describes the technical rules for new drinking water installations and specifies the associated correct selection of the pipe diameter. This design standard has been amended several times over the past decades and the pipe diameters specified therein have been adjusted so that a specific pipe diameter was also valid while a specific design standard was valid. Due to the empirical determination of a specific trend function from one or more specific pipe diameter(s), each design standard for pipe diameters is assigned a specific trend function that can be used to calculate the maximum pressure loss. In addition to DIN 1988 and its various versions, DIN EN 806, for example, can also be used.

A suitable trend function can thus be determined via the age of the building in order to determine the maximum pressure losses more precisely than using the representative, mean trend function T3.

Provision can thus be made for the control electronics to expect the age of the building to be input. Accordingly, the age of the building can be specified by the user. The control electronics then selects one of the trend functions according to the age of the building entered. For this purpose, all trend functions can be stored in the control electronics, for example in the form of a table of values or in the form of a mathematical function. In order to minimize the storage requirement, the design factor k _A can be used, with each building age being assigned a design factor k _A and being selected by the user after the building age has been entered. Only one trend function, for example the mean trend function T3, then needs to be stored in the control electronics, which is then simply multiplied by the design factor k _A .

Investigations have shown that the trend function for drinking water installations with a relatively high geodetic height should be steeper than for drinking water installations with a lower geodetic height. For this reason, in order to improve the accuracy when determining the maximum pressure loss, it is advantageous to make the gradient of the trend function dependent on the geodetic height H _geo . For this purpose, a height factor k _E to be multiplied by the trend function can be taken into account, which is greater the higher the geodetic height is. Below a limit value of 40 m, for example, this height factor can be 1, for example, and increase linearly above the limit value, for example it can be 2 at 125 m, so that the gradient is doubled.

Claims (15)

1. Method for adjusting a proportional pressure control curve (1) in the control electronics of a pressure boosting system to supply a hydraulic network in a building with a number of discharge points, characterised by the control electronics, from three system values comprising

   - a volume flow value (Q_100%) of a desired maximum volume flow on the pressure control curve (1),

   - an elevation value (H_geo) of a geodetic elevation and

   - a flow pressure value (p_FL) of a desired flow pressure at the least favourable discharge point,
   already determining a minimum pressure (po=o) at a volume flow of zero and a maximum pressure (p_Q100%) at the maximum volume flow, in which the pressure control curve (1) is formed by a connecting line between the minimum pressure (p_Q=0) and the maximum pressure (p_Q100%) and is adjusted by the control electronics.
2. Method according to claim 1, characterised by the volume flow value (Q_100%) forming a standard value established at the factory, the confirmation or change of which is expected by the control electronics.
3. Method according to claim 2, characterised by the standard value corresponding to the volume flow at the maximum hydraulic output of the pressure boosting system.
4. Method according to claim 1, 2 or 3, characterised by the volume flow value (Q_100%) forming an input value that can be specified by the user, the input of which is expected by the control electronics.
5. Method according to one of the preceding claims, characterised by the elevation value (H_geo) forming an input value to be specified directly by the user, the input of which is expected by the control electronics.
6. Method according to one of the claims 1 through 4, characterised by the elevation value (H_geo) being determined from a building height specified by the user, the input of which is expected by the control electronics.
7. Method according to one of the claims 1 through 4, characterised by the elevation value (H_geo) being determined from a number of floors specified by the user, notably a number of floors and a floor height, the input of which is expected by the control electronics.
8. Method according to one of the preceding claims, characterised by the pressure value (p_FL) forming a standard value established at the factory, preferably 3bar, the confirmation or change of which is expected by the control electronics.
9. Method according to one of the preceding claims, characterised by the pressure value (p_FL) forming an input value that can be specified by the user, the input of which is expected by the control electronics.
10. Method according to one of the preceding claims, characterised by the elevation value (H_geo) being used to calculate a geodetic pressure value (p_geo), and the minimum pressure (po=o) being formed from the sum of this geodetic pressure value (p_geo) and the flow pressure value (p_FL).
11. Method according to one of the preceding claims, characterised by the volume flow value (Q_100%) being used to calculate a maximum pressure loss (Δp_loss,max) using a trend function (T1-T5), and the maximum pressure (p_Q100%) being formed from the sum of the minimum pressure (po=o) and the maximum pressure loss.
12. Method according to claim 11, characterised by the trend function (T1-T5) describing the dependency of the maximum pressure loss (Δp_loss,max) of the volume flow (Q) according to a root function, the slope of which is defined by a layout factor (k_A) that can be selected.
13. Method according to claim 12, characterised by a predefined mean value of the layout factor (k_A) being used as standard.
14. Method according to claim 12 or 13, characterised by the control electronics expecting the specification of a building age for the building, and selecting the layout factor (k_A) from a number of stored layout factors based on the building age input by the user.
15. Pressure boosting system to supply a hydraulic network in a building with a number of discharge points, comprising at least one pump assembly and control electronics to control said pump assembly, characterised by the control electronics being configured to execute the method according to one of the claims 1 through 14.

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