DE202014104435U1 - heating system - Google Patents

Abstract

Heating system, comprising a heat generator (1) with a circulating pump (2) and with a volume flow sensor (3), a control device (4) being provided to control the circulating pump (2) and to acquire measured values from the volume flow sensor (3) The heat generator (1) is designed to be hydraulically connected to a heating circuit (7) via a flow connection (5) and a return connection (6), the control device (4) for adapting an actual residual head of the heat generator (1) between the flow connection (5) and the return connection (6) is designed to a required target residual delivery head, characterized in that, in order to determine the actual residual delivery head, control values of the circulating pump (2) and measured values of the volume flow sensor (2) which have been determined in advance for this heat generator (1) for all operating points and are currently recorded 3) evaluating allocation order (8) is stored in the control device (4).

Description

The invention relates to a heating system according to the preamble of patent claim 1.

A heating system of the type mentioned are out DE 10 2010 054 147 A1 known. This heating system consists of a heat generator with a circulating pump (not shown separately) and with a volumetric flow sensor, wherein a control device is provided for controlling the circulating pump and for detecting measured values of the volumetric flow sensor, the heat generator being hydraulically connected to a heating circuit via a flow connection and via a return connection is formed, wherein the control device (in this case, using the outside temperature value) is adapted to adapt an actual residual head of the heat generator between the flow connection and the return port to a required target residual head.

The invention has for its object to improve a heating system of the type mentioned. In particular, a heating system is to be created, which manages without additional pressure sensors (to carry out a pressure difference measurement between the flow connection and the return connection).

This object is achieved with a heating system of the type mentioned by the features listed in the characterizing part of the protection claim 1.

According to the invention, it is thus provided that, to determine the actual residual conveying height, an allocation order that has been previously determined for this heat generator for all operating points and currently detected activation values of the circulation pump and measured values of the volume flow sensor is stored in the control device, which implements the methodology described below.

In other words, according to the invention, the current value (actual value) of the residual head or the actual residual head of a heat generator with integrated circulation pump and integrated flow sensor from the current pump control, which is supplied by the control device of the heat generator, and the value measured by the integrated flow sensor Volumetric flow determined, with the aim of being able to adjust this actual value of the residual head by means of the control device to the required target residual head. For this purpose, the above-mentioned allocation order is already determined before the start of normal operation of the heating system and stored in the control device as useful information, the proviso "before starting" particularly preferred means that the allocation order already in the production of the heat generator once determined for each type and stored as part of the software of the control unit.

Other advantageous developments of the heating system according to the invention will become apparent from the dependent claims.

The sake of completeness is still on DE 101 39 510 B4 pointed out, in which the actual residual head, however, must be determined during operation of the heating system, ie as in the aforementioned prior art, with the help of an additional pressure difference meter.

The heating system according to the invention including its advantageous developments according to the dependent claims will be explained in more detail with reference to the drawing of a preferred embodiment.

It shows

1 schematically the heating system according to the invention;

2 an equivalent circuit diagram of the heating system according to 1 ;

3 a diagram in which the residual head RFH is plotted against the volume flow V at fixed pump control PA;

4 a diagram according to 3 with designation of the volume flow in the design state;

5 a diagram in which the residual head RFH is applied at different pump controls PA above the flow rate V.

6 a diagram in which the residual head RFH at "Δp constant" is plotted against the flow rate V; and

7 a diagram in which the residual head RFH is plotted against the volume flow V at "Δp rising".

1 shows schematically a heating system comprising a heat generator 1 with a circulation pump 2 and with a volumetric flow sensor 3 , wherein for controlling the circulation pump 2 and for the acquisition of measured values of the volumetric flow sensor 3 a control device 4 is provided, wherein the heat generator 1 over one Flow connection 5 and via a return port 6 hydraulically with a heating circuit 7 is formed connected, wherein the control device 4 to adjust an actual residual head of the heat generator 1 between the flow connection 5 and the return port 6 is formed to a required residual head height required during operation of the heating system. Essential for this heating system is now that for determining the actual residual head a pre-for this heat generator 1 for all operating points determined and currently recorded control values of the circulation pump 2 and measured values of the volumetric flow sensor 3 evaluative allocation order 8th in the control device 4 is deposited. The allocation order 8th is preferred as in the control device 4 stored software is formed.

In other words, according to the invention a heating system is provided, in which one with a circulation pump 2 and a volumetric flow sensor 3 provided heat generator 1 is used, the circulation pump 2 with a control device 4 is controlled, with the control device 4 Measured values of the volumetric flow sensor 3 be detected, the heat generator 1 via a flow connection 5 and via a return port 6 hydraulically with a heating circuit 7 is connected, wherein with the control device 4 an actual residual head of the heat generator 1 between the flow connection 5 and the return port 6 is adapted to a required target residual head. Essential for the method according to the invention is now that the actual residual head with the help of an advance for this heat generator 1 for all operating points determined, currently detected control values of the circulation pump 2 and measured values of the volumetric flow sensor 3 evaluating and in the control device 4 deposited allocation order 8th is determined.

In detail:
At the in 1 The solution shown is the circulation pump 2 speed-controlled, ie the pump control PA is preset via a pulse width modulation signal (PWM signal) as a percentage value.

From the circulation pump 2 a pressure difference referred to as delivery height FH is supplied. The pressure difference, outside the heat generator between the flow connection 5 and the return port 6 is present and the heating circuit 7 is made available, is referred to as residual head RFH.

Through the internal piping and a heat exchanger 9 , which is the recording of a burner 10 generated heat is generated within the heat generator 1 a hydraulic resistance R _G, which causes a pressure loss .DELTA.p _G. The following relationship applies here: Δp _G = R _G V ² , where V denotes the volume flow. In 2 is an equivalent circuit diagram representing this situation.

The residual delivery height RFH thus results from the delivery height FH of the circulation pump 2 minus the pressure loss Δp _G in the heat generator 1 ,

The delivery height FH depends on the pump control PA and the volume flow V. This connection is made with the hydraulic resistance R _{UP of} the circulation pump 2 described by: FH = a + b PA - R _UP V ² .

Thus, the residual conveying height RFH can be represented by: RFH = FH - Δp _G = a + b PA - (R _UP + R _G ) V ² = a + b PA - RV ² .

With fixed or constant pump control PA thus results in in 3 illustrated characteristic curve, in which for a higher volume flow, a lower residual head RFH for the heating circuit 7 results.

To the heating circuit 7 in the design state (in all radiators 11 of the heating circuit 7 flow the nominal volume flows) to provide a predetermined residual head RFH _SOLL , the circulation pump must 2 be set to a sufficiently high pump control PA (see 4 ).

For low volume flow requirement (only a few radiator valves 12 opened) is then too large residual head RFH, resulting in noises on the radiator valves 12 can lead. In addition, the excessively high residual flow head RFH, with low demand, leads to higher volume flows in the radiators 11 flow as necessary. This then has an increase in the return temperature at the return connection 6 As a result, which is unfavorable for the so-called condensing.

The heating system according to the invention will be described in more detail below:
For a regulation, the actual value of the residual conveying height RFH must be known. However, this is not available as measured size. Instead of sensors for pressure difference measurement at the heat generator 1 to install, is the already existing flow sensor 3 used.

The starting point of the method according to the invention is the representation of the residual conveying height RFH by: RFH = a + b PA - RV ² . (*)

In order to determine the parameters a, b and R in the aforementioned equation (*), the residual delivery height RFH of the heat generator becomes, for various values of the pump control PA 1 measured as a function of the volumetric flow V on a test bench. 5 shows a typical characteristic field.

On the basis of these measurements, the parameters a, b and R are determined by means of mathematical calculation methods (so-called compensation methods).

Thus, with the aid of the aforementioned equation (*), the value of the residual delivery height from the current pump drive PA and the measured volume flow can now be determined at any time and used as the actual value for a control. The new value for the pump control PA then results according to the operating mode described below ("Δp constant" and "Δp rising") and the control method.

The two just mentioned, the control of the circulation pump 2 Defining and energy-efficient and comfortable operation of the heating system enabling modes are in the 6 and 7 shown.

In the "Δp constant" operating mode, a constant residual head RFH _{SOLL is} delivered for each requirement state. The operating mode "Δp rising" takes into account the fact that at higher flow rates additional pressure losses occur over the piping and internals.

• – Aktuellen Wert der Pumpenansteuerung PA aus der Regelung auslesen;
• – Aktuellen Wert des Volumenstroms V bestimmen (der Volumenstromsensor liefert diesen Wert an die Regelung);
• – IST-Wert der Restförderhöhe durch die zuvor genannte Gleichung (*) bzw. die in der Regelungseinrichtung hinterlegte Zuweisungsordnung 8 bestimmen.

The methodology for determining the current residual head RFH in the control of the heat generator can thus be described as follows:

• - read the current value of the pump control PA from the control;
• - determine the current value of the volumetric flow V (the volumetric flow sensor supplies this value to the control);
• - Actual value of the residual conveying height by the aforementioned equation (*) or the allocation order stored in the regulating device 8th determine.

For this, the values or parameters a, b and R for this heat generator must be 1 already determined and in the control unit 4 (as allocation order 8th ) be deposited.

In the following, the solution according to the invention will be described again in other words:
The residual head RFH is a variable (pressure difference), which consists of the head of the circulating pump FH and the pressure loss in the heat generator 1 results. It depends on the speed of the circulation pump 2 and the volume flow V of the heating medium.

The respective remaining residual head RFH could simply by a differential pressure gauge on the flow connection 5 and return port 6 of the heat generator 1 be determined.

This should be avoided in the inventive solution.

Instead, the (brand new) heat generator 1 (once per series) on a test bench, with a differential pressure gauge and depending on the pump control PA of the circulation pump 2 and the volume flow V. Constant parameters (see above) are determined for a function of the residual delivery height RFH, which is otherwise a function of the volume flow V and the pump drive PA.

The function together with the determined parameters, as explained, as assignment order 8th in the control device 4 of the heat generator 1 saved.

After delivery of the heat generator, the current residual head RFH _IST (based on the previously determined parameters) can be determined solely on the basis of the pump control PA and the volume flow V and changed by changing the pump control PA.

• a) ”Δp konstant” (also konstanter Differenzdruck) Bei dieser Variante soll unabhängig vom tatsächlichen Volumenstrom eine bestimmte Restförderhöhe RFH erreicht werden. Praktisch heißt dies, RFH_IST wird aus der Pumpenansteuerung PA und dem Volumenstrom V bestimmt und mit RFH_SOLL verglichen. Liegt RFH_IST unter RFH_SOLL, wird die Pumpenansteuerung PA entsprechend erhöht (und umgekehrt).
• b) ”Δp ansteigend” (also ansteigender Differenzdruck) Bei dieser Variante soll RFH_SOLL mit steigendem Volumenstrom V größer werden. Eine entsprechende Funktion ist in der Regelung hinterlegt. Praktisch heißt dies wiederum, RFH_IST wird aus der Pumpenansteuerung und dem Volumenstrom bestimmt und mit RFH_SOLL verglichen. Dabei ergibt sich der tatsächlich Wert von RFH_SOLL aus dem aktuellen Wert des Volumenstroms V. Liegt RFH_IST unter RFH_SOLL, wird die Pumpenansteuerung PA entsprechend erhöht (und umgekehrt).

For the target value of the residual head RFH _SOLL , which may change during operation of the heating system, can different specifications in the control device 4 be saved, namely

• a) "Δp constant" (ie constant differential pressure) In this variant, a certain residual head RFH should be achieved independently of the actual volume flow. Practically this means, RFH _IST is from the pump control PA and the flow rate V determined and compared with RFH _SOLL . RFH is under _IS RFH _SOLL, the pump control PA is correspondingly increased (and vice versa).
• b) "Δp rising" (ie increasing differential pressure) In this variant, RFH _{SOLL should increase} with increasing volume flow V. A corresponding function is stored in the control. In practice, this means that RFH _IST is determined from the pump control and the flow rate and compared with RFH _SOLL . In this case, the actual value of RFH _SOLL results from the current value of the volume flow rate V. If RFH _IST under RFH _SOLL, the pump control PA is correspondingly increased (and vice versa).

LIST OF REFERENCE NUMBERS

1

heat generator

2

circulating pump

3

Flow Sensor

4

control device

5

Flow connection

6

Return connection

7

heating circuit

8th

allocation Rules

9

heat exchangers

10

burner

11

radiator

12

radiator valve

FH

head

RFH

Residual head

Ap

pressure difference

PA

pump control

V

flow

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010054147 A1 [0002]
• DE 10139510 B4 [0008]

Claims (2)

Heating installation, comprising a heat generator ( 1 ) with a circulation pump ( 2 ) and with a volume flow sensor ( 3 ), wherein for controlling the circulating pump ( 2 ) and for the acquisition of measured values of the volumetric flow sensor ( 3 ) a control device ( 4 ) is provided, wherein the heat generator ( 1 ) via a flow connection ( 5 ) and via a return port ( 6 ) hydraulically with a heating circuit ( 7 ) is formed, wherein the control device ( 4 ) for adjusting an actual residual head of the heat generator ( 1 ) between the flow connection ( 5 ) and the return port ( 6 ) is formed to a required target residual conveying height, characterized in that for determining the actual residual conveying height a preliminary for this heat generator ( 1 ) for all operating points and currently detected activation values of the circulating pump ( 2 ) and measured values of the volumetric flow sensor ( 3 ) evaluating allocation order ( 8th ) in the control device ( 4 ) is deposited. Heating installation according to claim 1, characterized in that the allocation order ( 8th ) than in the scheme ( 4 ) stored software is formed.

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