Primary Circuit Pump Control Based on Secondary Circuit Flow Demand

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Solution Overview

Problem

Existing heating and cooling systems lack demand-dependent control for speed-controlled centrifugal pumps located on the primary side of transfer points, leading to inefficient energy usage due to unregulated flow rates.

Innovation Solution

A method for controlling the volume flow of a first circulation pump in the primary circuit based on the volume flow of the secondary circuit downstream of the transfer point, using a functional dependence to ensure energy-efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the primary-side circulation pump operates at high flow rate to ensure sufficient supply to consumers, then the consumers receive adequate heating or cooling, but energy consumption increases unnecessarily

Engineering Contradiction:
Improvesupply sufficiency to consumersVSAvoidenergy consumption of primary-side pump
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control system continuously monitors the actual volume flow in the secondary circuit and uses this feedback to dynamically adjust the primary-side pump's volume flow. The controller compares the actual secondary circuit flow with the desired flow and modifies the primary pump operation accordingly, ensuring energy-efficient operation while maintaining supply sufficiency.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static or predetermined pump operation to dynamic volume flow control. The primary-side circulation pump's volume flow is continuously adapted based on real-time conditions in the secondary circuit, allowing the system to respond to changing consumer demands and optimize energy consumption throughout operation.

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If demand-dependent control is implemented for primary-side pumps, then energy efficiency improves, but measurement and control complexity increases

Engineering Contradiction:
Improveenergy efficiency of pump operationVSAvoidcontrol system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The controller acts as an intermediary between the secondary circuit flow measurement and the primary-side pump actuation. It receives flow information from the secondary circuit, processes this data, and generates appropriate control signals for the primary pump, simplifying the overall control architecture while enabling demand-dependent operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces complex mechanical flow control mechanisms with electronic sensing and control. Flow meters and electronic controllers monitor and adjust pump operation, substituting mechanical complexity with electronic systems that offer precise control with simpler overall system architecture.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3374699B2Method for controlling a centrifugal pump, and associated pump system
Publication Date: 2026.03.04 WILO SE
  • EP3374699B2 patent drawingFigure 1
  • EP3374699B2 patent drawingFigure 2
  • EP3374699B2 patent drawingFigure 3

AI summary

The invention relates to a method for controlling at least one first circulation pump (17b, 17c) of a heating or cooling system (1) having a primary circuit (2, 2a) and a secondary circuit (4, 30a) coupled therewith at a transfer point (3, 29). The first circulation pump (17, 17b, 17c, 17b') conveys a heating or cooling medium in the primary circuit (2, 2a), and in the second secondary circuit (4, 30a), at least one second circulation pump (12, 17d) is located that conveys a heating or cooling medium in at least one partial area of the secondary circuit (4, 30a). The volume flow rate (formula I) of the first circulation pump (17, 17b, 17c, 17b') is controlled in functional dependence on the volume flow rate (formula II) of the secondary circuit (4, 30) behind the transfer point (3, 29). In this way, a demand-based, and thus an energy-efficient control of the primary-side circulation pump is achieved. The invention further relates to a pump system, comprising the at least one first and the at least one second circulation pump for carrying out the method.