DE3503741A1 - Method for the effective output regulation of pumps in the case of variable volume flows in heating systems or for other systems comprising other media - Google Patents

Abstract

If drive power is to be saved by matching, for heating systems with variable volume flows or for other systems comprising other media, the output power of the pumps to the required volume flow of the installation, this requires a suitable controlled variable. The controlled variable used hitherto, system differential pressure equals pump differential pressure, does not permit effective power output regulation in this case, since this controlled variable picks up as a deviation only the increasing differential pressure in accordance with the pump curve. The controlled variable used according to the invention is therefore a consumption-side pipe subsystem resistance. The novel controlled variable thus takes into account, at the same time, the pipe system resistance of the plant which decreases with the square of the reduced volume flow, so that the pump output power can largely be matched to the actual requirement. Via a speed control of the pump drive it is thus possible to achieve a maximum saving in pumping energy.

Description

Heinz Schilling KG ^ ζ Π ^ 7 Z

Development and planning Möhlenring 53, 4152 Kempen 1, phone 02152/53002

2,

Method for the effective control of the output of pumps with variable Volume flows in heating systems or for other systems with other media.

Introduction:

Heating systems or other systems for other media are in usually designed for volume flows that meet a maximum requirement z. B. in the heating system of the required heat in winter corresponding. So much for post-regurgitation that is variable in quantity in such systems lungs are installed, e.g. B. by regulators, thermostatic valves, etc., in this way, the required amount in circulation is considerably reduced, depending on consumption.

In conventional systems, the reduced amount in circulation, depending on the type of built-in units and system characteristic, increases more or less the pump differential pressure, which is then either throttled at the control organs or regulated by overflow or multiple flows.

Another possibility is to use a speed control ζ. B. to use the pump drive, which reduces the volume flow as a function of an increasing pump differential pressure regulates the pump speed. The purpose of this measure is to improve the system quality (avoidance of flow noise, etc.) and at the same time to save primary energy for the pump drive.

The power control systems on the market are, however, due to the specified control variable of the pump differential pressure to be maintained, severely limited in their effectiveness, especially since the priority is supply security before saving on pumping work and * the function of the plant areas must be guaranteed. If you wanted to use the speed control of a pump drive to adjust the power of the unit to the pipe network characteristic,

ORIGINAL

· - 'ES 05/1/85

Heinz Schilling KG

Development and planning Möhlenring 53, 4152 Kempen 1, phone 02152/53002

the total pipe network resistance would correspond to the required and to be set pump differential pressure and would therefore be at the same time the decisive setpoint controlled variable.

However, if you want to regulate the volume flow of the pump units according to the actual requirement and at the same time the maximum To save possible pump work, a relevant, system-specific controlled variable must be used for control.

_W W-'jr L f W ^ -

Heinz S ¹ C hi Hi rig K * 6 '

Development and planning 3 5 O 3 7 A J

Möhlenring 53, 4152 Kempen 1, phone 02152/53002

Description of the invention

The idea according to the invention is now to be used as a controlled variable for a effective volume flow control a relevant system-specific partial differential pressure of the system (total or partial pipe network resistance the consumption side). There is also the possibility of saving The closer the differential pressure measuring point is to the quantity-variable consumption point, the greater the pump work.

The advantage of this method is that the aforementioned Controlled variable also takes into account the pipe network resistance, which decreases quadratically with a reduced volume flow. This means that when using a Speed control of the pump drive the power output of the pump largely approximates the actual power requirement of the system, so that the maximum possible pump work can be saved at each operating point.

If there is a widely ramified pipe network, there may be several relevant control variables. In this case, the controlled variables are to be connected to the control loop in parallel.

Example;

A simplified shown heating system according to Figure 1 is required for the consumers (1 - 4) have a circulation rate of 4 χ 2.5 = 10 ti / h a differential pressure of 60 kPa. The circulation pump (5) is therefore for 10 m * at 60 kPa. See the pump diagram according to FIG. 2, operating point (1). Are now z. B. 3 consumers switched off according to Figure 1 (2-4), the necessary volume flow is only 2.5 m ³ / h. In normal operation of a circulating pump without power control, the pump differential pressure increases according to the diagram according to FIG according to the pump curve (5). See operating point (2)

ORIGINAL

. - -. · ES 05/1/85

Heinz Schilling KG

Development and planning O D U ο / A- I

Möhlenring 53, 4152 Kempen 1, Tel .: 02152/53002

-x -

By means of the known speed control according to FIG. 1 (6), the pump can now be reduced in its output by reducing the speed up to the differential pressure to be maintained (7). In the present example, according to the changed pump characteristic according to FIG. 2 (6), this allows a maximum reduction at the operating point (3). If, however, according to the invention, one takes the relevant system-specific controlled variable according to FIG. 1, namely the consumption-side partial pipe network resistance δ ρ (8) or even better δ ρ (9), the output of the circulating pump can be significantly reduced, in the best case according to the system characteristic curve (8) up to the operating point (4).

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Claims (1)

.. ....., -. - ■ '■ · _ES 05/1/85 '* ■■ · .. ■■■ ♦ '■■' · ■ '■: i Heinz Schilling KG * 3 ζ Π ^ 7/1 ^! Development and planning Möhlenring 53, 4152 Kempen 1, Tel .: 02152/53002 -X- Method for the effective control of the output of pumps with variable Volume flows in heating systems or also for other systems other media. Claim; Method for the automatic power control of pumps with variable volume flows according to the actual volume flow requirement, characterized in that a relevant system-specific partial pipe network resistance of the system consumption side is used for power control is used as a controlled variable.