Heat Exchanger Pump Speed Control to Prevent Minimum Speed Energy Loss

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Solution Overview

Problem

Existing heat exchanger control methods are inefficient, particularly in low-load operations, as they waste energy due to the use of throttle valves and pumps operating at fixed speeds, which cannot meet small power requirements due to minimum speed limitations.

Innovation Solution

Implementing a control system that monitors and adjusts the pump speed and operating parameters to prevent the pump from reaching its minimum speed, maintaining operation above this limit by changing other system parameters such as hydraulic resistance or admixture, ensuring efficient energy transfer and regulation across varying load conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the pump speed is reduced to meet small power requirements, then energy efficiency is improved, but the pump reaches its minimum speed limit and cannot operate further

Engineering Contradiction:
Improveenergy efficiencyVSAvoidspeed adjustment range
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent changes the operating parameters of the primary circuit (hydraulic resistance, admixture ratios, temperature levels) to enable further reduction of pump speed below the original minimum limit. By adjusting these parameters, the system maintains stable operation while extending the speed adjustment range, allowing the pump to operate at lower speeds to meet small power requirements efficiently.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system dynamically adjusts multiple operating parameters in coordination with pump speed changes. Instead of relying on a fixed minimum speed limit, the system continuously adapts hydraulic resistance, admixture, and temperature parameters to maintain stable operation across a broader speed range, enabling the pump to operate efficiently at variable speeds including below the original minimum.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If a throttle valve is used to change volume flow, then control precision is improved, but energy is wasted due to pressure loss across the valve

Engineering Contradiction:
Improvecontrol precisionVSAvoidenergy waste
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent replaces the mechanical throttle valve system with a pump speed control system. Instead of using a throttle valve to create pressure loss for flow control, the system directly controls the pump speed to match the required volume flow. This substitution eliminates the energy waste associated with throttle valve pressure drops while maintaining precise control capability through electronic speed regulation.

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

Solution Approach 2:

The system changes from controlling flow through pressure drop (throttle valve) to controlling flow through speed variation (pump motor). By changing the fundamental control parameter from pressure to speed, the system achieves the same flow control precision without the energy penalty of throttling, as the pump operates efficiently across its extended speed range.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the pump operates at fixed speed, then system simplicity is maintained, but energy efficiency deteriorates in low-load operations

Engineering Contradiction:
Improvesystem simplicityVSAvoidenergy efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent transforms the fixed-speed pump system into a variable-speed system with dynamic parameter adjustment. The pump speed is continuously adapted to match the actual load requirements, and operating parameters (hydraulic resistance, admixture, temperature) are dynamically adjusted in coordination. This dynamic operation maintains system simplicity in control logic while dramatically improving energy efficiency during low-load operations compared to fixed-speed operation.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances energy efficiency and response speed by maintaining pump operation above the minimum speed, allowing for precise control of heat transfer and meeting power demands without excessive energy waste, thereby improving the control of media parameters in heat exchangers.

Implementation Method 1

a heat exchanger to transfer heat between a heat transfer medium on its primary side and a medium on its secondary side

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the heat transfer medium... is actively circulated on the primary side with at least one pump

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3757396A1Method and system for controlling a medium parameter of the medium on the secondary side of a heat exchanger
Publication Date: 2020.12.30 WILO SE
  • EP3757396A1 patent drawingFigure 1
  • EP3757396A1 patent drawingFigure 2
  • EP3757396A1 patent drawingFigure 3

AI summary

The invention relates to a method for controlling a media parameter, in particular the temperature of the medium on the secondary side of a heat exchanger (8), in which a heat transfer medium is pumped through the heat exchanger (8) in a primary circuit (1) of the heat exchanger (8) by means of a pump (5) and the medium on the secondary side is tempered by this medium, wherein the media parameter control is effected by changing the speed of the pump (5) as the control variable, wherein when a predetermined lower limit is undershot or reached by a reduction in the speed of the pump (5), a change in an operating parameter of the primary circuit (1) is triggered to counteract the reduction, in particular by preventing the pump speed from dropping to a minimum speed. The invention also relates to a system for controlling a media parameter of the secondary-side medium of a heat exchanger (8).