Hydronic System Flow Control Module to Prevent Low ΔT Syndrome

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Solution Overview

Problem

Hydronic systems often suffer from the 'low ΔT syndrome' due to mismatched temperature differentials between primary and secondary loops, leading to inefficient energy use and operation, which existing control methods fail to adequately mitigate.

Innovation Solution

A flow control module that continuously adapts the thermal power supply and demand in hydronic systems by controlling the speed of pumps and valves, using a closed-loop feedback mechanism to minimize signed deviation values, allowing for stable operation regardless of unknown or varying design temperature differentials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If existing control methods regulate primary loop flow to achieve certain effects in secondary loop, then control simplicity is maintained, but the low ΔT syndrome cannot be mitigated

Engineering Contradiction:
Improvecontrol simplicityVSAvoidenergy efficiency
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent implements a closed-loop feedback control system that continuously monitors the actual temperature differential (ΔT) between supply and return lines and adjusts the primary loop flow rate accordingly. The controller compares the actual ΔT with the design ΔT and modulates the primary pump speed or valve position to maintain optimal temperature differential, thereby preventing the low ΔT syndrome and improving energy efficiency while maintaining operational simplicity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adapts the primary loop flow rate based on real-time thermal load conditions and actual temperature differential measurements. Rather than using fixed flow rates, the system continuously adjusts flow parameters to match varying building thermal demands, ensuring optimal energy efficiency across different operating conditions while keeping the control mechanism straightforward.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If demand flow devices perform event-based triggered re-adjustment of temperature differential supply setpoint, then adaptation to changing conditions is achieved, but system complexity increases

Engineering Contradiction:
Improvetemperature differential adaptationVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses continuous feedback from temperature sensors and flow meters to automatically adjust the primary loop flow rate, eliminating the need for event-based triggered re-adjustment of supply setpoints. The controller continuously monitors actual ΔT and makes real-time adjustments, achieving adaptability to changing thermal loads without the complexity of event-triggered control logic or multiple setpoint adjustments.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-adjustment by automatically regulating primary loop flow based on measured temperature differential and thermal load conditions. The control algorithm autonomously determines optimal flow rates without requiring external intervention, event triggering, or complex coordination between multiple control devices, thereby achieving adaptability with minimal system complexity.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If new components are switched into the hydronic system, then system functionality is enhanced, but the design temperature differential becomes unknown or difficult to determine

Engineering Contradiction:
Improvesystem component flexibilityVSAvoiddesign temperature differential information
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent implements continuous monitoring of the actual temperature differential using temperature sensors at key system points, allowing the control system to automatically determine and adapt to the effective ΔT regardless of which components are active. This feedback mechanism eliminates the need to pre-know or pre-configure design temperature differentials for different component combinations, as the system continuously measures and adjusts based on actual operating conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically determines the effective design temperature differential through continuous measurement and adaptation rather than relying on fixed pre-configured values. When new components are introduced or switched in, the system automatically adapts by measuring actual temperature differences and adjusting primary loop flow accordingly, maintaining optimal performance without requiring recalibration or loss of adaptability.

Inventive Principle:
Principle #15Dynamics

4Loss of energy

If the flow control module continuously adapts thermal power supply to demand, then energy efficiency is improved, but control complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidflow control complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements a closed-loop feedback control system that continuously monitors thermal power demand through temperature differential measurements and adjusts primary loop flow rate accordingly. The controller compares actual ΔT with target ΔT and automatically modulates pump speed or valve position to maintain optimal energy efficiency. This feedback-based approach achieves continuous adaptation of thermal power supply to demand using straightforward control logic, improving energy efficiency without excessive control complexity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3525060B1Flow control module and method for controlling the flow in a hydronic system
Publication Date: 2021.04.21 GRUNDFOS HLDG
  • EP3525060B1 patent drawingFigure 1~1b
  • EP3525060B1 patent drawingFigure 2
  • EP3525060B1 patent drawingFigure 3

AI summary

The present disclosure is directed to a flow control module (39) for controlling one or more pumps in a hydronic system (1), wherein the hydronic system (1) comprises - a primary side (3) with a first port (21) in fluid connection with an output (23) of at least one source element (7), a second port (27) in fluid connection with an input (29) of the at least one source element (7), and at least one controllable primary side flow actuator (9) for providing a primary side flow (q1), - a secondary side (5) with a third port (31) in fluid connection with an input (33) of at least one load element (11), a fourth port (35) in fluid connection with an output (37) of the at least one load element (11), and at least one controllable secondary side flow actuator (13) for providing a secondary side flow (q2), and - an intermediary transfer element (17) between the primary side (3) and the secondary side (5), wherein the intermediary transfer element (17) is in fluid connection with the first port (21), the second port (27), the third port (31) and the fourth port (35). The flow control module (39) is configured to adapt the thermal power transfer of the intermediary transfer element (17) by controlling the primary side flow (q1) by means of the at least one controllable primary side flow actuator (9) and/or the secondary side flow (q2) by means of the at least one controllable secondary side flow actuator (13) in a continuous or regularly closed-loop manner based on minimising a signed deviation value (ΔΔv) being correlated with the thermal power transfer of the intermediary transfer element (17).