Fan Speed Control Using Venturi Valve Modeling to Minimize Power
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Solution Overview
Problem
Existing air distribution or extraction systems with venturi air valves face challenges in efficiently controlling fan speed due to the lack of direct correlation between venturi valve position and required fan speed or pressure, leading to excessive energy consumption and inadequate terminal satisfaction.
Innovation Solution
A control system that models pressure losses in ducts, incorporating the minimum pressure of venturi air valves, to set a fan set point based on the highest needed pressure across branches, ensuring efficient fan operation and energy minimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors and switches are installed to measure pressure across venturi valves for fan speed control, then pressure control accuracy is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent creates a virtual model (copy) of the venturi valve and duct system that replicates pressure behavior without physical sensors. The model uses mathematical relationships between airflow, duct resistance, and venturi characteristics to calculate pressure, eliminating the need for expensive pressure transmitters while maintaining control accuracy
Solution Approach 2:
The patent replaces the mechanical/physical measurement system (pressure sensors, switches, wiring) with a computational model-based system. The controller uses software algorithms to simulate pressure measurements based on airflow data and system characteristics, substituting physical measurement infrastructure with digital computation
2Use of energy by moving object
If fan speed is reduced to minimize energy consumption, then energy efficiency is improved, but terminal satisfaction may be compromised
Solution Approach 1:
The patent implements a feedback control system where the virtual model continuously calculates required pressure based on actual airflow measurements and terminal demands. The controller adjusts fan speed in real-time to maintain adequate pressure at all terminals, ensuring satisfaction while minimizing energy use through precise, dynamic optimization rather than fixed speed settings
Solution Approach 2:
The patent transitions from static fan speed control to dynamic control based on real-time system conditions. The virtual model continuously updates pressure requirements as airflow demands change, allowing the fan speed to dynamically adapt to actual needs, ensuring terminals are satisfied only when necessary and enabling energy minimization when full capacity is not required
3Device complexity
If existing duct models are used for pressure calculation, then modeling simplicity is maintained, but accuracy for venturi valve systems is insufficient
Solution Approach 1:
The patent applies local quality by incorporating venturi-specific characteristics into the model only where venturi valves are located in the duct system. The virtual model uses different mathematical relationships for sections with venturi valves versus standard duct sections, maintaining simplicity in non-venturi areas while achieving accuracy in venturi-critical zones through localized model enhancement
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 stabilizes pressure control, minimizes fan power usage, and ensures targeted airflow to meet terminal demands, even with venturi air valves, by accurately calculating pressure losses and adjusting fan speed accordingly.
Implementation Method 1
In a venturi air valve, the cone moves on a shaft, independent of the control system. The position may not directly relate to needed fan speed or pressure.
Data Source
AI summary
For air distribution or extraction, fan speed is controlled using modeling to account for venturi air valves. A minimum pressure for each venturi air valve is incorporated into the model. The pressure losses for various duct airpaths to terminal units is calculated based, in part, on the minimum pressure of any venturi valve. The fan set point or operation is established based on the highest needed pressure in the various airpaths connected with the fan.