Controller and method for managing a flow unit
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Solution Overview
Problem
Conventional building automation systems face challenges in maintaining consistent control performance across varying system conditions, often leading to inefficient energy usage and slow reaction times due to fixed nominal setpoints that do not adapt to dynamic changes.
Innovation Solution
A dynamic calculation of nominal flow approach that adjusts control parameters based on real-time pressure drops and positions of flow control elements, allowing for consistent performance across a wide range of system conditions without the need for extensive tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed nominal setpoint is used for controller tuning, then the device is optimized for a fixed system design condition, but it performs poorly when system conditions change (e.g., slow reaction time at lower end of operating range)
Solution Approach 1:
The patent implements dynamic nominal flow calculation that automatically adjusts to changing system conditions. The controller computes nominal flow in real-time based on actual pressure drops and flow control element positions, replacing fixed setpoints with adaptive parameters that maintain consistent control performance across the full operating range.
Solution Approach 2:
The system changes the parameter used for control tuning from a fixed nominal setpoint to a dynamically calculated nominal flow value. This parameter transformation allows the controller to adapt to varying pressure drops and flow conditions without requiring manual retuning, resolving the contradiction between reliability and adaptability.
2Adaptability or versatility
If a Venturi air valve is used for self-adjustment, then the valve adapts to changing system conditions, but the energy operating cost increases
Solution Approach 1:
The patent replaces the mechanical Venturi air valve self-adjustment mechanism with a computational approach. The controller uses software-based dynamic nominal flow calculation based on sensor inputs (pressure drops and position), eliminating the need for energy-consuming mechanical adjustment components while achieving the same adaptability.
Solution Approach 2:
The system provides self-service through automatic dynamic nominal flow calculation without requiring external energy input or mechanical adjustment devices. The controller autonomously computes and applies the correct nominal flow value based on real-time system conditions, achieving adaptation without the energy penalty of Venturi valves.
3Speed
If conventional controller tuning is performed at upper end of design condition range, then timely response is achieved at upper end, but slow reaction occurs at lower end of design condition range
Solution Approach 1:
The patent makes the nominal flow parameter dynamic rather than fixed. By continuously calculating nominal flow based on actual pressure drops and positions, the system maintains optimal control reaction speed across the entire operating range, eliminating the trade-off between upper and lower end performance.
Data Source
AI summary
There is described a controller and method for managing a flow unit. A measured pressure drop corresponding to a full open position of a flow control element is detected. A calibration pressure drop at full open is established based on the measured pressure drop, and relative pressure drops are calculated based on the calibration pressure drop at full open and calibration pressure drops corresponding to calibration positions of the element. Subsequent to calibration, an operation pressure drop of the flow unit and an operation position of the element are detected. A dynamic nominal is determined based on the operation pressure drop and a particular relative pressure drop corresponding to the operation position. An operation relative flow and a relative flow setpoint are determined based, in part, on the dynamic nominal. The operation position of the flow control element is controlled based the operation relative flow and relative flow setpoint.