Ventilation Fan Pressure Tuning for Faster Branch Airflow Balancing

Solution Overview

Problem

Existing ventilation system tuning methods are inefficient, time-consuming, and require iterative adjustments, making it difficult to minimize pressure losses and achieve optimal energy efficiency, especially due to challenges in accurately measuring pressures and air flow rates in field conditions.

Innovation Solution

A method utilizing a frequency converter controlled electric motor to select the branch with the greatest pressure loss, adjust fan rotational speed based on fan characteristic curves, and maintain constant fan pressure to optimize air flow rates across all branches without additional measurement equipment, thereby minimizing electric energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If iterative adjustment methods are used to tune ventilation branches, then air flow rates can be set to desired levels, but the tuning process becomes extremely time consuming

Engineering Contradiction:

Improveair flow rate accuracyVSAvoidtuning time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The method performs preliminary identification of the branch with greatest pressure loss before actual tuning begins. This preliminary action allows the tuner to start with the most critical branch first, avoiding unnecessary iterative adjustments across all branches and significantly reducing total tuning time while maintaining accurate air flow rate setting.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The tuning process is segmented into distinct phases: first identifying and tuning the branch with greatest pressure loss, then systematically tuning remaining branches one-by-one. This segmentation prevents the need for complete iterative re-adjustment of all branches, reducing time while preserving measurement precision for each segment.

Inventive Principle:

Principle #1Segmentation

2Productivity

If multiple branches are tuned simultaneously, then tuning speed increases, but pressure changes cause flow rates to drop requiring re-adjustment

Engineering Contradiction:

Improvetuning speedVSAvoidair flow rate stability

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The method performs preliminary identification of the branch with greatest pressure loss before actual tuning begins. This preliminary action allows the tuner to start with the most critical branch first, avoiding unnecessary iterative adjustments across all branches and significantly reducing total tuning time while maintaining accurate air flow rate setting.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The tuning process is segmented into distinct phases: first identifying and tuning the branch with greatest pressure loss, then systematically tuning remaining branches one-by-one. This segmentation prevents the need for complete iterative re-adjustment of all branches, reducing time while preserving measurement precision for each segment.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If hand held measurement equipment is used in field conditions, then portability is achieved, but accurate measurement of pressures and air flow rates becomes difficult

Engineering Contradiction:

ImproveportabilityVSAvoidpressure and air flow rate measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The method enables the ventilation system itself to provide the measurement information needed for tuning. By using the frequency converter's built-in capabilities to measure shaft power and calculate air flow rates from manufacturer data, the system eliminates the need for external measurement equipment while maintaining high measurement precision through model-based calculations.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The method replaces mechanical measurement equipment (hand-held pressure gauges and flow meters) with an electronic calculation system based on the frequency converter's electrical measurements. This substitution uses electrical signals and mathematical models to determine air flow rates, achieving both portability and measurement accuracy without physical measurement devices.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If fan speed is adjusted to compensate for pressure drops when opening new branches, then air flow rates are maintained, but energy consumption increases

Engineering Contradiction:

Improveair flow rate maintenanceVSAvoidfan energy consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The method changes the control parameter from fan speed adjustment to control valve adjustment. By keeping fan speed constant and using control valves to regulate air flow to each branch, the system maintains desired air flow rates without the energy penalty of continuously adjusting fan speed, thereby reducing overall energy consumption while preserving flow rate precision.

Inventive Principle:

Principle #35Parameter changes

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 allows for fast, reliable, and energy-efficient tuning of ventilation systems by minimizing pressure losses and optimizing specific fan power, ensuring efficient energy use and compliance with regulatory standards.

Implementation Method 1

controlling the ventilation fan to produce a desired air flow rate into said selected branch by using fan characteristic shaft power to air flow rate curves, a shaft power estimate from the frequency converter and by adjusting the rotational speed of the electric motor with the frequency converter

Methodology Applied

Scientific EffectFan characteristic curves:

Implementation Method 2

adjusting the control valves in each of the remaining branches one-by-one so that the desired air flow rate to each branch is delivered while the fan is controlled by the frequency converter to produce constantly the reference pressure

Methodology Applied

Scientific EffectPressure control through frequency conversion:

Data Source

PatentEP2660527B1Method for tuning a ventilation system

Publication Date: 2015.07.22 ABB TECH OY

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AI summary

The method comprises the steps of selecting the branch with the greatest pressure loss, opening the control valve in said selected branch and closing the control valves in all other branches, controlling the ventilation fan to produce the desired air flow rate into said selected branch by using fan characteristic shaft power to air flow rate curves, a shaft power estimate from the frequency converter and by adjusting the rotational speed of the electric motor with the frequency converter so that the desired air flow rate is achieved, calculating simultaneously the fan pressure corresponding to the desired air flow rate from fan characteristic fan pressure to air flow rate curves based on the desired air flow rate and the rotational speed of the electric motor, and saving the calculated fan pressure in the frequency converter as a reference pressure for the next step, adjusting the control valves in each of the remaining branches one-by-one so that the desired air flow rate to each branch is delivered while the fan is controlled by the frequency converter to produce constantly the reference pressure.