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Title:
METHOD FOR OPERATING A FLUID DELIVERY SYSTEM, AND DELIVERY PUMP
Document Type and Number:
WIPO Patent Application WO/2016/016212
Kind Code:
A1
Abstract:
A method for operating a fluid delivery system which comprises at least one delivery pump which delivers delivery fluid is provided, in which a speed of the at least one delivery pump is varied in a controlled manner, wherein the speed variations differ by 25% or less than 25% based on a normal speed of the at least one delivery pump during normal operation, and the speed variations are carried out temporarily for a period of time of five minutes or less than five minutes, a reaction of the fluid delivery system to the speed variation is determined, information regarding the fluid delivery system is obtained from the reaction and, by means of the information obtained, the fluid delivery system is characterized and/or adjustments to the at least one delivery pump are carried out.

Inventors:
LAING OLIVER (DE)
Application Number:
PCT/EP2015/067210
Publication Date:
February 04, 2016
Filing Date:
July 28, 2015
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
XYLEM IP MAN SÀRL (LU)
International Classes:
F04D15/00; F24D19/10
Domestic Patent References:
WO2008067919A12008-06-12
Foreign References:
EP1593851A22005-11-09
EP1323984A12003-07-02
DE102009050083A12011-04-28
US20100252029A12010-10-07
EP1323986B12011-01-19
EP0736826B11999-11-24
EP1640616A22006-03-29
DE4006186C21996-09-26
EP1171714B12005-03-16
DE69924301T22006-04-13
EP1286240B12004-08-11
EP2562424A22013-02-27
DE102007054313A12009-05-07
US20090121034A12009-05-14
DE102013109134A12015-02-26
Attorney, Agent or Firm:
HOEGER, STELLRECHT & PARTNER PATENTANWÄLTE MBB (Stuttgart, DE)
Download PDF:
Claims:
Patent claims

Method for operating a fluid delivery system which comprises at least one delivery pump which delivers delivery fluid, comprising : varying a speed of the at least one delivery pump in a controlled manner, wherein the speed variations differ by 25% or less than 25% based on a normal speed of the at least one delivery pump during normal operation, and the speed variations are carried out temporarily for a period of time of five minutes or less than five minutes; determining a reaction of the fluid delivery system to the speed variation; obtaining information regarding the fluid delivery system from the reaction; and, by means of the information obtained, at least one of (i)

characterizing the fluid delivery system and (ii) carrying out adjustments to the at least one delivery pump.

Method according to Claim 1, characterized in that the speed variations within a period of time are clocked and in particular are carried out periodically.

Method according to Claim 2, characterized in that a clock period is greater than or equal to 1 s and smaller than or equal to 3 s, in particular in conjunction with the obtaining of information regarding circulating rates.

Method according to Claim 2, characterized in that a clock period is greater than or equal to 60 s and smaller than or equal to 300 s, in particular in conjunction with the obtaining of information regarding temperatures.

5. Method according to one of the preceding claims, characterized in that 20 or more than 20 and in particular 100 or more than 100 speed variations are carried out within the period of time with the speed variations.

6. Method according to one of the preceding claims, characterized in that the speed of the at least one delivery pump is optionally adapted as a result of the speed variations.

7. Method according to one of the preceding claims, characterized in that a temperature of the delivery fluid is measured at the at least one delivery pump.

8. Method according to Claim 7, characterized in that the at least one

delivery pump is assigned at least one temperature sensor for measuring a temperature of the delivery fluid, which temperature sensor is in particular arranged on the at least one delivery pump and is in particular integrated into the at least one delivery pump.

9. Method according to one of the preceding claims, characterized in that a control device controls the variation in the speed of the at least one delivery pump.

10. Method according to Claim 9, characterized in that the control device is integrated into the at least one delivery pump.

11. Method according to Claim 9 or 10, characterized in that the control device comprises an evaluation device for obtaining the information.

12. Method according to one of Claims 9 to 11, characterized in that the control device comprises a storage device for storing data.

13. Method according to one of the preceding claims, characterized in that the speed variation of the at least one delivery pump is carried out during normal operation of the fluid delivery system and in particular speed variations are carried out in such a manner that the normal operation is maintained.

14. Method according to one of the preceding claims, characterized in that the speed variations differ by 20% or less than 20% and in particular by 15% or less than 15% based on a normal speed of the at least one delivery pump during normal operation.

15. Method according to one of the preceding claims, characterized in that a reaction of the fluid delivery system to a speed variation is determined as a function of time.

16. Method according to Claim 15, characterized in that a changing speed of the fluid delivery system in response to a variation in the speed of the at least one delivery pump is determined.

17. Method according to one of the preceding claims, characterized in that the speed variation takes place in stages or continuously.

18. Method according to one of the preceding claims, characterized in that the fluid delivery system has a feed section and a return section.

19. Method according to Claim 18, characterized in that a heat-generating device is arranged between feed section and return section.

20. Method according to Claim 18 or 19, characterized in that the at least one delivery pump is arranged in the feed section and an increase of the speed is carried out and a dropping of a temperature of the delivery fluid at the at least one delivery pump is determined.

21. Method according to Claim 20, characterized in that a temperature

difference between feed section and return section is determined from the dropping of the temperature.

22. Method according to Claim 20 or 21, characterized in that a time interval is determined between a speed increase and a temperature reaction.

23. Method according to Claim 22, characterized in that a system volume is determined from the determined time interval and a flow rate.

24. Method according to one of the preceding claims, characterized in that relative circulating volumes are determined in a temporally spaced manner and in particular periodically.

25. Method according to Claim 24, characterized in that determined system volumes are stored.

26. Method according to Claim 25, characterized in that determined system volumes are compared with stored values.

27. Method according to Claim 25 or 26, characterized in that a determined system volume is compared with a stored maximum system volume.

28. Method according to one of the preceding claims, characterized in that a flow rate is determined by means of the at least one delivery pump.

29. Method according to one of the preceding claims, characterized in that one or more of the following values are determined : flow rate,

temperature of the delivery fluid at the at least one delivery pump, system volume, temperature difference between a feed section and return section.

30. Method according to one of the preceding claims, characterized in that a design of the fluid delivery system is determined.

31. Method according to one of the preceding claims, characterized in that the adjustment is carried out in such a manner that an energy balance of the fluid delivery system as a whole is optimized.

32. Method according to one of the preceding claims, characterized in that the following adjustment is carried out: increasing a speed of the at least one delivery pump when a heat-generating device is in operation, and lowering the speed when the heat-generating device is not in operation.

33. Method according to one of the preceding claims, characterized in that the fluid delivery system is a heating system.

34. Delivery pump for delivering fluid, comprising an impeller (40) and a control device (48) which is designed in such a manner that the method according to one of Claims 1 to 33 is carried out thereon.

35. Delivery pump according to Claim 34, characterized by a temperature sensor (46).

Description:
Method for operating a fluid delivery system, and delivery pump

The present disclosure relates to the subject matter disclosed in German application No. 10 2014 110 911.2 of July 31, 2014, which is incorporated herein by reference in its entirety and for all purposes.

BACKGROUND OF THE INVENTION

The invention relates to a method for operating a fluid delivery system which comprises at least one delivery pump.

The invention relates to a delivery pump for delivering fluid, comprising an impeller and a control device.

EP 1 323 986 Bl discloses a method for controlling a heating circulating pump, the rotational speed of which is controllable, in which the rotational speed of the pump can be varied along a control curve and the control curve is automatically adapted as a function of the heat requirement of the heating system. The pipe network resistance of the heating system is used as a measure of the heat requirement, and, in order to determine a shallow and a steep pipe network characteristic curve, the pump is successively activated with at least two different rotational speeds and the control curve is

ascertained with reference to said determined characteristic numbers of the pipe network.

EP 0 736 826 B2 discloses a power control, which is conducted as a function of temperature, for an electrically operated pump unit for delivering heating water in a heating system, wherein the pump unit can be operated with at least two different power stages. The power control has a monitoring unit, the monitoring unit uses at least one temperature sensor located in the heating system to record the temperature profile of the heating water by measuring the temperature and the periods of time in which the temperature drops, and the monitoring unit predetermines for the power control a power stage which is dependent on the recorded temperature profile characteristic. EP 1 640 616 A2 discloses a heating circulating pump which is driven by an electric motor and has control and regulating electronics designed in such a manner that the pump, at time intervals, automatically starts up from operating points differing from the current operating point in order to determine at least one characteristic value of the pipe network of the heating system, and the current rotational speed of the pump is automatically selected with reference to the determined characteristic value.

WO 2008/067919 Al discloses a method for controlling a heating circulating pump, the rotational speed of which is controllable, in a heating system, the flow resistance of which is variable as a function of the room temperature, in which the time profile of the delivery rate or of a pump variable linked to the delivery rate is detected, and it is determined using the detected variable whether a sufficient supply or an undersupply or oversupply of the heating system takes place by means of the pump, wherein the pump is automatically activated in a correcting manner in the event of a determined undersupply or oversupply.

DE 40 06 186 D2 discloses a method for regulating the velocity of a pump driven by a velocity controlled electromotor.

EP 1 171 714 Bl (DE 699 24 301 T2) discloses a control device for controlling the operating parameters of a centrifugal pump associated with flow, velocity or pressure. EP 1 286 240 Bl discloses a method for determining a pump-characteristic.

EP 2 562 424 A2 discloses a method and an equipment for controlling a multiple fluid distribution system. SUMMARY OF THE INVENTION

The invention is based on the object of providing a method of the type mentioned at the beginning, by means of which a fluid delivery system can be optimally operated .

This object is achieved according to the invention in that a speed of the at least one delivery pump is varied in a controlled manner, wherein the speed variations differ by 25% or less than 25% based on a normal speed of the at least one delivery pump during normal operation, and the speed variations are carried out temporarily for a period of time of five minutes or less than five minutes, a reaction of the fluid delivery system to the speed variation is determined, information regarding the fluid delivery system is obtained from the reaction and, by means of the information obtained, the fluid delivery system is characterized and/or adjustments to the at least one delivery pump are carried out.

In the case of the method according to the invention, the fluid delivery system is actively tested by the at least one delivery pump by specific, relatively small speed variations being carried out temporarily. This active testing takes place via the at least one delivery pump. The corresponding reactions are then evaluated. For example, corresponding system information can be derived by a

temperature variation of the delivery fluid at the delivery pump during a speed variation. The system information can be obtained here in particular with regard to the level of the temperature change and also with regard to the time delay of the temperature change.

On account of a relatively brief execution of the speed variations within the period of time of five minutes or less, in particular of clocked speed variations, averaging over a plurality of variations can be achieved . The fluid delivery system is characterized by means of the information obtained and/or adjustments to the at least one delivery pump are carried out by means of the information obtained . An optimization of the fluid delivery system, for example, with regard to energy consumption, can then be carried out.

It is advantageous if the speed variations within a period of time in which they are carried out are clocked and in particular are carried out periodically. As a result, the fluid delivery system can be actively "investigated" in a simple manner by means of the at least one delivery pump, with the normal operation of the fluid delivery system being able to be maintained . Repeated testing with relatively small speed changes then takes place; meaningful results are thereby obtained. An averaging can therefore be carried out in a simple manner. Good accuracy can be achieved.

For example, a clock period of a speed variation is greater than or equal to 1 s and smaller than or equal to 3 s, in particular in conjunction with the obtaining of information regarding circulating rates. As a result, an active "investigation" can be carried out in a simple manner with little disturbance of the normal operation.

It can also be advantageous if a clock period is greater than or equal to 60 s and smaller than or equal to 300 s, in particular in conjunction with the obtaining of information regarding temperatures. It can thus be ensured that a corresponding dynamic temperature equilibrium can be set.

It is provided in particular that 20 or more than 20 and in particular 100 or more than 100 speed variations are carried out within the period of time with the speed variations. This makes it possible to achieve averaging over the speed variations in order thereby to obtain meaningful information regarding the fluid delivery system, which information can be used in turn for

adjustments of the at least one delivery pump. In particular, the speed of the at least one delivery pump is adapted as a result of the speed variations if such an adaptation is necessary. It is very particularly advantageous if a temperature of the delivery fluid is measured at the at least one delivery pump. A temperature reaction can thereby be determined in the event of a speed variation .

In particular, the at least one delivery pump is assigned at least one

temperature sensor for measuring a temperature of the delivery fluid, which temperature sensor is in particular arranged on the at least one delivery pump and is in particular integrated into the at least one delivery pump. A

temperature reaction can thereby be determined in a simple manner. In particular, a control device controls the variation in the speed of the at least one delivery pump. A specific speed variation can thereby be carried out, with information regarding the fluid delivery system then being able to be obtained from the corresponding reaction of the latter. In one exemplary embodiment, the control device is integrated into the at least one delivery pump. A simple system construction can thereby be realized .

It is very particularly advantageous if the control device comprises an evaluation device for obtaining the information. This makes it possible, for example, for adjustments of the fluid delivery system to be made in a simple manner and in particular also at the at least one delivery pump.

It can furthermore be provided that the control device comprises a storage device for storing data. As a result, for example, a comparison of current determined values (such as, for example, relative circulating volumes) with stored values can be carried out in order to obtain corresponding information. It is very particularly advantageous if the speed variation of the at least one delivery pump is carried out during normal operation of the fluid delivery system, such as, for example, during a heating operation of a heating system, and in particular speed variations are carried out in such a manner that the normal operation is maintained . As a result, thorough testing of the system can be carried out "imperceptibly" by the delivery pump during normal operation.

It is advantageous if the speed variations differ by 20% or less than 20% and in particular by 15% or less than 15% based on a normal speed of the at least one delivery pump during normal operation. The speed variation can thus be carried out in a normal operating mode.

In particular, it is advantageous if a reaction of the fluid delivery system to a speed variation is determined as a function of time. Information regarding the fluid delivery system, such as, for example, relative circulating volumes, can be obtained from a corresponding time delay.

It is then advantageous if a changing speed of the fluid delivery system in response to a variation in the speed of the at least one delivery pump is determined .

The speed variation can take place in stages or continuously, depending on the application.

In particular, the fluid delivery system has a feed section and a return section, wherein a heat-generating device is arranged between feed section and return section. The heat-generating device is, for example, a boiler or comprises a boiler.

In one exemplary embodiment, the at least one delivery pump is arranged in the feed section and an increase of the speed is carried out and a dropping of a temperature of the delivery fluid at the at least one delivery pump is determined . If the speed of the delivery pump is increased during the heating operation of the boiler, dropping of the temperature of the fluid at the delivery pump then takes place. The return temperature requires time for adaptation and the heat capacity is not adapted or not immediately adapted . The result of the speed increase is then a temperature reduction which then results in a new equilibrium. The temperature reduction itself is a measure of the temperature range between feed section and return section. System

information can likewise be determined from the time interval until the new equilibrium is established.

In particular, a temperature difference between feed section and return section is determined from the dropping of the temperature. Said temperature difference can be determined here directly by temperature measurement only at the at least one feed pump. In principle, no temperature measurement at the return section is required.

It is likewise advantageous if a time interval is determined between a speed increase and a temperature reaction. The system volume between a heat generator and the at least one delivery pump can be determined from said time interval . There are basically two temperature reactions to a speed change: if the speed of the at least one delivery pump is initially raised, the temperature drops at the at least one delivery pump. As soon as, however, delivery liquid has passed through heating elements, the temperature rises again at the at least one delivery pump as a second reaction since the temperature in the return section increases. The two reactions may differ.

In particular, a system volume is then determined from the determined time interval and a flow rate, in particular as a product of said variables. In one exemplary embodiment, system information is determined in a temporally spaced manner and in particular periodically. As a result, even time-triggered information can be determined via the fluid delivery system. For this purpose, an intervention in the system is made by repeated (clocked) acceleration and braking of the circulating rate and the duration is observed . The longer a duration, the greater the relative circulating rate.

In particular, determined relative circulating volumes are stored and

determined system volumes compared with stored values, wherein in particular a comparison with stored maximum relative circulating volumes takes place. It is thus possible to determine, for example, what percentage portion of the water flows at all in the fluid delivery system and how many valves in the fluid delivery system are closed or open.

It is advantageous if a flow rate is determined by means of the at least one delivery pump. Additional information regarding the fluid delivery system is thereby obtained . In principle, the flow rate can be determined from a measured motor power and a known rotational speed of the at least one delivery pump.

It is furthermore advantageous if one or more of the following values are determined : flow rate, temperature of the delivery fluid at the at least one delivery pump, system volume, temperature difference between a feed section and return section. Relevant system information is thereby obtained . In particular, the values are determined in a temporally resolved manner.

It is also possible in principle to determine a design of the fluid delivery system, for example in the form of a floor heating circuit or in the form of a high-temperature heating circuit.

It is furthermore advantageous if the adjustment of the at least one delivery pump with reference to the obtained information is carried out in such a manner that an energy balance of the fluid delivery system as a whole is optimized .

For example, the following adjustment is carried out: the speed of the at least one delivery pump is increased when a heat-generating device is in operation, and the speed is lowered when the heat-generating device is not in operation . As a result, in principle, the frequency of switching operations (into

operation/out of operation) of the heat-generating device can be reduced, with the operating times being extended when the heat-generating device is in operation. This results in an effective and energy-saving manner of operating the heat-generating device.

The invention furthermore relates to a delivery pump for delivering fluid of the type mentioned at the beginning . According to the invention, the control device is designed in such a manner that the method according to the invention is carried out thereon.

In particular, the delivery pump comprises a temperature sensor. The latter is arranged internally on the delivery pump. Said (at least one) temperature sensor can determine the temperature of delivery fluid at the delivery pump. In conjunction with the method according to the invention, system information can be obtained from the temperature and in particular the temporal development of the temperature. The delivery pump itself can be controlled in turn by said system information by, for example, a new speed of the delivery pump being set.

BRIEF DESCRIPTION OF THE DRAWINGS

The description below of preferred embodiments serves for the more detailed explanation of the invention in conjunction with the drawings, in which :

Figure 1 shows a schematic partial illustration of a first exemplary

embodiment of a fluid delivery system; Figure 2 shows a schematic sectional illustration of an exemplary

embodiment of a delivery pump (circulating pump); Figure 3 shows a schematic illustration of a second exemplary embodiment of a fluid delivery system;

Figure 4 shows a schematic illustration of a third exemplary embodiment of a fluid delivery system;

Figure 5 shows schematically, in the case of an exemplary embodiment, the temporal relationship between a speed of a delivery pump (rotational speed n) and the temperature Ti at the delivery pump in the event of variation of the speed of the delivery pump;

Figure 6 shows schematically a family of characteristics of a delivery pump

(delivery head as a function of flow rate) in the event of different speeds ni and n 2 , and shows schematically, in broken lines, a resistance curve of a fluid delivery system, and shows schematically, by the arrows, the effect of an increase of the speed from ni to n 2 ; and

Figure 7 shows schematically temporal profiles (averaged over ten

iterations) of the flow rate in the event of a change in the hydraulic resistance and in the event of two different circulating rates.

DETAILED DESCRIPTION OF THE INVENTION

A first exemplary embodiment of a fluid delivery system, which is shown in a block diagram in Figure 1 and is denoted there by 10, is designed as a heating system. Said liquid delivery system comprises a heat-generating device 12. The latter is, for example, a boiler 14 with a burner 16.

The fluid delivery system 10 has a feed section 18 and a return section 20. The feed section 18 leads to heat consumers 22, wherein only one heat consumer 22 is indicated in Figure 1. The heat consumers 22 are, for example, heating elements with thermostatic valves connected upstream. Hot delivery fluid (in particular water) is conveyed in the feed section 18 by a delivery pump 24 (circulating pump). The return section 20 leads from the heat consumer or the heat consumers 22 to the boiler 14. Cooled delivery fluid (after dispensing heat to the heat consumer or the heat consumers 22) is conveyed back via the return section 20 to the heat-generating device 12. A circulation and in particular closed circulation is formed via the return section 20 and the feed section 18.

The temperature of the delivery fluid in the feed section 18 is higher than the temperature of the delivery fluid in the return section 20 when the fluid delivery system 10 is operated in a normal mode; a temperature spread ΔΤ is formed between the feed section 18 and the return section 20.

An exemplary embodiment of a delivery pump 24 (circulating pump) is known, for example, from DE 10 2007 054 313 Al or US 2009/0121034. Reference is made expressly and in full to said documents.

The pump 24 (Figure 2) comprises an electric motor 26 with a stator 28 and a rotor 30. The electric motor 26 comprises a motor circuit 32. In the exemplary embodiment, the motor circuit 32 is arranged in a circuit housing 34.

The rotor 30 is mounted on a convex bearing body 38 and in particular a bearing ball via a bearing shell 36. A spherical bearing is formed by the bearing shell 36 and the bearing body 38. An impeller 40 is connected to the rotor 30 for rotation therewith. The impeller 40 rotates about a rotation axis 42 in a delivery chamber 44. In one exemplary embodiment, the electric motor 26 is electronical ly commutated .

The delivery pump 24 is assigned a temperature sensor 46 which measures the temperature of the delivery fl uid at the del ivery pump 24. The (at least one) temperature sensor 46 is in particular arranged on the del ivery pump 24.

In one exemplary embodiment, the temperature sensor 46 is integrated into the del ivery pump 24 (cf. Figure 2) . In particular, the temperature sensor 46 is arranged at the delivery chamber 44. Said temperature sensor is arranged here with respect to the stator 28 and the motor circuit 32 in such a manner, and in particular is thermal ly insulated in relation to the latter in such a manner, that the temperature Ti of the delivery fl uid can be measured at the delivery pump 24 via the temperature sensor 46 without a substantial thermal influence of the stator 28 or of the motor circuit 32.

The delivery pump 24 is assig ned a control device 48. The control device 48 can impart certain control commands to the del ivery pump 24 for varying the speed of the delivery pump 24. The speed of the delivery pump 24 here is the speed of the impeller 40 and in particular the rotational speed of the impeller 40.

In principle, the control device 48 can be separate and , for example, an apparatus arranged spaced apart from the del ivery pump 24. In one

exemplary embod iment, said control device is integ rated in the del ivery pump 24 and in particular is arranged in the circuit housing 34.

The control device 48 furthermore comprises an evaluation device 52 by means of which certain information, as explained in more detail below, can be eval uated . On the basis of this information, control commands can be imparted to the del ivery pump 24 itself by the eval uation device 52. In one exemplary embodiment, the control device 48 comprises a storage device 54 in which data can be stored.

A second exemplary embodiment of a fluid delivery system, which is shown schematically in a block diagram in Fig. 3 and is denoted there by 56, is basically of the same design as the fluid delivery system 10, wherein the same reference numbers are used for identical elements. In this exemplary embodiment, a mixer valve 58 is arranged between the feed section 18 and the return section 20. In the case of the fluid delivery system 10, the delivery pump 24 pumps delivery fluid through the system. The fluid delivery system 56 with the additional mixer valve 58 makes it possible for the delivery pump 24 to be able to deliver delivery fluid at a lower temperature than is provided by the heat-generating device 12. By means of the mixer valve 58, "cold" delivery fluid from the return section 20 upstream of the delivery pump 24 can be mixed with the "hot" delivery fluid from the heat-generating device 12.

The fluid delivery system 56 is, for example, a floor heating system.

A third exemplary embodiment of a fluid delivery system, which is shown schematically in Figure 4 and is denoted there by 60, comprises a heat- generating device as in the case of the fluid delivery system 10 and 56. The same reference numbers are used for identical elements.

The fluid delivery system 60 has a heat-generating side 62 and a consumer side 64. A hydraulic switch 66 is arranged between the heat-generating side 62 and the consumer side 64. The hydraulic switch 66 is formed, for example, by a pipe extending perpendicularly with respect to the direction of gravity. The consumer side 64 is decoupled from the heat-generating side 62 via the hydraulic switch 66. This is necessary or expedient, for example, if the heat- generating device 12 has a higher minimum throughflow than can be guaranteed on the consumer side 64. The fluid del ivery system 60 comprises a first feed section 68, a second feed section 69, a first return section 74 assigned to the first feed section 68 and a second return section 75 assig ned to the second feed section 69. In the first feed section 68, a del ivery pump 70 which pumps heated delivery fluid to the hyd raulic switch 66 is arranged on the heat-generating side 62.

In the second feed section 69, a further del ivery pump 72 which pumps hot delivery fl uid to the heat consumers 22 is furthermore provided on the consumer side 64.

In the first return section 74, del ivery fluid flows from the hyd raul ic switch 66 and from there in the second return section 75 to the heat-generating device 12. In the second return section 75, del ivery fluid flows from the heat consumers 22 to the hyd raul ic switch 66.

Information regard ing the corresponding fluid del ivery system 10 or 56 or 60 can in principle be obtained by the delivery pump 24 or 70. In particu lar, the temperature Ti of the delivery fluid is determined at the del ivery pump 24 or 70 by the temperature sensor 46.

The flow rate can also be ascertained by a corresponding del ivery pump 24 or 70. For example, the electric motor is operated at a certain first rotational speed , and the flow rate Q is determined from a measured motor power P and the rotational speed . In this connection, reference is made to German patent application No . 10 2013 109 134 of 5 September 2013, to which reference is made in ful l .

In accordance with the invention, the delivery pump 40 or 70 is used to obtain further information regarding the correspond ing fl uid delivery system 10 or 56 or 60. The speed of the delivery pump 24 (the rotational speed of the impeller 40) is varied here in a specific manner, a reaction of the corresponding fluid delivery system 10 or 56 or 60 is determined and information regarding the

corresponding fluid delivery system 10 or 56 or 60 obtained from the reaction.

In principle, this information in turn can also be used in order to adjust one or more parameters of the corresponding fluid delivery system, that is to say, in order actively to adjust the fluid delivery system. Corresponding control commands are then provided in particular via a connecting device of the control device 48.

The variation in the speed of the corresponding delivery pump (such as the delivery pump 24) takes place here in particular starting from the normal operating mode, in which the corresponding fluid delivery system 10 or 56 or 60 is operated . The speed of the corresponding delivery pump is then changed in particular in such a manner that said normal operating mode is not substantially impaired, i.e. the operation, such as a heating operation, is not interrupted . In particular, the speed of the delivery pump 24 varies by 25% or less than 25% and in particular by 20% or less than 20% or 15% or less than 15% and, for example, by approximately 10% based on the speed in the normal operating mode. In particular, an increase in speed starting from the normal operating mode takes place.

The speed variation takes place within a relatively short period of time which amounts to five minutes or less. The changes in the speed within said short period are clocked and in particular periodic. As a result, relatively high accuracy can be achieved with minimized disturbance of the normal operation of the fluid delivery system. For example, a period of a speed variation lies within the range between 1 s to 3 s, i.e. is greater than or equal to 1 s and smaller than or equal to 3 s. Such "rapid" clocking is advantageous in particular if information regarding the circulating rate is intended to be used or is intended to be obtained. A "slower" clocking, which is in particular greater than or equal to 1 minute and smaller than or equal to 5 minutes, is advantageous if information regarding temperatures is intended to be determined or intended to be obtained.

In one exemplary embodiment, which is explained with reference to Figure 5, for example in the case of the fluid delivery system 10, the delivery pump 24 is operated at a speed ni in the normal operating mode. The speed is then periodically increased by a step to a speed n 2 . For example, the speed increase, based on the speed ni, is approximately 10%. The corresponding profile of the speed of the delivery pump 24 is shown at the top in Figure 5.

The control device 48 here gives the corresponding commands for speed variation to the delivery pump 24 (specifically to the electric motor 26 thereof).

The speed is increased in particular when the heat-generating device 12 is in operation, i.e. when delivery fluid is heated there. By means of the increase in the speed of the delivery pump 24, a temperature reduction of the delivery fluid takes place at the feed pump 24. This is indicated in the lower curve in Figure 5. This temperature reduction can be determined via the temperature sensor 46.

During normal operation and when the heat-generating device is in operation, the delivery fluid has a temperature Ti. By means of an increase in the speed of the delivery pump 24, the temperature drops to T 3 . This temperature drop can be attributed to the fact that the heat capacity is not adapted or not immediately adapted to the increase in speed when a correspondingly designed heat-generating device 12 is present. The return temperature requires time for the adaptation. The temperature spread ΔΤ between the feed section 18 and the return section 20 can be determined from the temperature drop to T 3 . The ratio Ti/T 3 at least approximately corresponds to the ratio nz/ni. A temperature sensor 76 in the return section 20 is indicated in Figure 1. In the case of the solution according to the invention, this temperature sensor is no longer necessary since the temperature T 2 in the return section 20 can be at least approximately derived from the temperature T 3 which is measured by the temperature sensor 46.

The mentioned measurement with the temperature reduction can also be carried out in the fluid delivery system 56 with the mixer 58 as long as hot water arrives more rapidly from the heat-generating device 12 than

corresponds to the reaction time of the mixer valve 58. The reaction time of commercially available mixer valves 58 is typically approximately 120 seconds. The fluid delivery system 10 reacts (in a first reaction) with a certain time delay to the increase in the speed of the delivery pump 24. A corresponding time interval At is indicated in Figure 5. The time delay At in the temperature reaction of the delivery fluid at the delivery pump 24 depends on the system volume between heat generator and delivery pump 28. In the normal operating mode at the speed ni, there is a temperature equilibrium at a certain temperature Ti. After the speed increases, a new temperature equilibrium with the temperature T 3 is established by the delay At. This can be attributed to two reactions: first of all, the temperature drops to T 3 . As soon as the water has passed through heating elements, the temperature rises again somewhat (to T 4 ) since the return section arrives somewhat hotter. The temperature in the return section is denoted in Figure 5 by T RL .

For example, in the event of a speed change of 10%, the difference Ti-T 3 is typically a tenth of the difference Ti-T RL .

The delay results here from the distance of the delivery pump 24 from the heat-generating device 12. The smaller said distance, the more rapidly the reaction, which was caused by the speed change of the delivery pump 24, arrives at the delivery pump 24.

The time delay At multiplied by the flow rate Q, which in turn can be determined via the delivery pump 24, then produces the system volume between heat generator and delivery pump 28, wherein the system volume is moved via the delivery pump 24. The duration of time until the temperature T 4 as equilibrium temperature is reached is a measure of the overall system volume.

As a result, the moving system volume, which provides information regarding the fluid delivery system 10, can be determined via the delivery pump 24 and the corresponding variation in the speed . The temperature changes are measured during the heating operation. The changes are determined in particular from an approximately linear temperature rise curve.

The system volume which can be correspondingly determined provides information as to whether the fluid delivery system 10 is or is not well adjusted . In a fluid delivery system 10 in which heating valves or floor heating circuits are well adjusted, the time interval At should be correspondingly small (in particular based on the length of the interval in which the delivery pump 24 is operated at the speed n 2 ) since delivery fluid is intended to arrive at the same time in the return section 20. For example, the relative circulating volume during a night reduction of the system or at the beginning of a heating-up process in a morning can therefore also be determined (cf. Figure 6). In this case, corresponding rooms to be heated are too cold if this is compared with a heating valve setting, and therefore all of the heating valves are intended to be open. This therefore results in a relative circulating volume which can serve as a maximum possible value and can therefore serve as the basis for comparisons. The reaction of the delivery pump 24 in the event of a speed change is shown in principle in Figure 6. Figure 6 shows a family of characteristic (delivery head or delivery pressure over flow rate) for different speeds ni and n 2 of the delivery pump 24. A resistance curve 78 of the corresponding fluid delivery system is furthermore shown. At a certain time (indicated in Figure 6 by the reference number 80), the speed is increased from ni to n 2 . If it is assumed that the delivery pump 24 reacts immediately (has an infinite reaction speed), the delivery head then increases abruptly as a result. This is indicated in Figure 6 with reference number 82. The delivery pump 24 subsequently reacts by means of a movement along the corresponding characteristic curve for the speed n 2 until the intersecting point with the resistance curve 78 is in turn reached. This is indicated in Figure 6 by the reference number 84.

This then means that a water column is moved at precisely the speed at which the friction losses in the fluid delivery system 10 correspond to the delivery head, but wherein a corresponding time is required for the speed n 2 with the new equilibrium. The time delay with which the new equilibrium is established at point 84 is a relative indicator of the circulating rate in the system. The greater the circulating rate, the longer the delivery pump needs in order to accelerate the circulating rate to the speed corresponding to point 84.

Figure 7 shows the resulting flow rate Q in the temporal dependency thereof in the event of a change in the hydraulic resistance for two different circulating rates (86 and 88, wherein the circulating rate is greater for the curve 88 than for the curve 86). The profile of the flow rate Q is measured here and averaged over ten iterations.

The curve 86 rises more steeply than the curve 88 because the greater circulating rate requires more energy for the acceleration.

The curves have been determined here in an equivalent manner to the procedure at which the system resistance is kept constant and the speed of a delivery pump (such as, for example, the delivery pump 24) is changed . The curves according to Figure 7 have been maintained by the fact that a ball valve has been rotated open and shut, as a result of which the relative circulating rate has changed . The reaction at the delivery pump is measured, i .e. it is measured how much energy the delivery pump has to expend for the acceleration of the circulating volume. In the case of the procedure in which the speed of the pump is changed, the reaction is measured according to the invention at the delivery pump; this also corresponds to the energy which the delivery pump has to expend for accelerating the circulating volume.

The corresponding information can be used in order to obtain information as to the heating requirement which is present.

For example, a corresponding determined system volume is stored in the storage device 54, wherein in particular a periodic speed increase takes place. Currently determined values are then compared with stored values and in particular maximum values. The control device 48 can in turn determine therefrom which percentage portion of the delivery fluid of the system is still flowing and, for example, how many valves are already closed .

This information can be obtained from the speed with which, and in particular the time delay with which, the fluid delivery system 10 reacts to changes in the speed of the delivery pump 24. In principle, the temperature Ti of the delivery fluid can be determined at the delivery pump 24 via the delivery pump 24 with the temperature sensor 46. In the event of a speed change, the temperature range ΔΤ can be determined . Furthermore, the flow rate can be determined . In addition, the relative circulating volume and the overall volume can be determined .

The design or adjustment of the fluid delivery system 10 can be determined from said information . Adjustments can be varied in turn therefrom in order in particular to optimize the entire system and in particular to optimize same with regard to energy consumption.

In one exemplary embodiment, for example, the efficiency of the heat- generating device 12 is optimized . In principle, a boiler 14 is operated more effectively if said boiler is in operation less frequently, but runs for longer when it is in operation. This can be achieved by the fact that the delivery pump 24 is operated at a higher speed when the heat-generating device 12 is in operation with the boiler 14. A smaller ΔΤ with a decrease in the

temperature of the delivery fluid in the feed section 18 thereby arises. Since the operation of the boiler 14 stops at a certain temperature, the boiler runs for longer. In the event of stopping of the operation of the boiler 14, a higher return temperature is generated, which increases the amount of heat which the delivery fluid absorbs before the boiler 14 is stopped . The reversal of this process in the cooling phase extends the cooling phase and, as a result, the efficiency is in turn increased .

In the case of the solution according to the invention, the fluid delivery system 10 or 56 or 60 is to a certain extent scanned by the delivery pump 24, by means of corresponding variation in speed, in order to obtain information regarding the fluid delivery system 10, 56, 60. Said information can be used as such or can be used in order to adapt the fluid delivery system 10, 56, 60 and in particular to optimize same with regard to the energy consumption thereof.

List of reference numbers

Fluid delivery system (first exemplary embodiment)

Heat-generating device

Boiler

Burner

Feed section

Return section

Heat consumer

Delivery pump

Electric motor

Stator

Rotor

Motor circuit

Circuit housing

Bearing shell

Bearing body

Impeller

Rotation axis

Delivery chamber

Temperature sensor

Control device

Evaluation device

Storage device

Fluid delivery system (second exemplary embodiment)

Mixer valve

Fluid delivery system (third exemplary embodiment)

Heat-generating side

Consumer side

Hydraulic switch

First feed section

Second feed section Delivery pump

Delivery pump

First return section Second return section Temperature sensor Resistance curve

Increase

Increase in delivery head Movement

Curve

Curve