Controller and method for managing a flow unit
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Solution Overview
Problem
Conventional building automation systems face challenges in maintaining optimal control performance across varying system conditions, often resulting in either over-cycling or slow reaction times, especially when dealing with airflow control in HVAC systems, which can lead to higher energy costs and inefficient operation.
Innovation Solution
A dynamic calculation of nominal flow approach is implemented, using a controller with input, processor, and output components to detect and adjust flow control elements based on measured and calibrated flows, 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 control tuning, then the device is optimized for a fixed system design condition, but it does not work well when the system resets the design condition to optimize for other conditions such as energy efficiency
Solution Approach 1:
The patent implements dynamic nominal flow calculation that automatically adjusts to changing system conditions. The controller continuously calculates nominal flow based on real-time measurements of actual flow and actuator position, replacing the fixed nominal setpoint with a dynamically updated value that adapts to varying operating conditions, thereby maintaining reliable control performance across different system states
Solution Approach 2:
The patent changes the parameter of nominal flow from a fixed design value to a dynamically calculated value based on real-time system measurements. By continuously updating the nominal flow parameter based on actual flow measurements and actuator positions, the system adapts to changing conditions while maintaining consistent control performance
2Speed
If the controller is tuned with the system at the upper end of the design operating condition range, then the controller responds in a timely manner to errors at the upper end, but it will be slow to react when the system is in the lower end of the design condition range
Solution Approach 1:
The dynamic nominal flow calculation ensures the controller maintains appropriate response characteristics across the entire operating range. By continuously adjusting the nominal flow based on actual measurements, the controller adapts its behavior to match current operating conditions, providing timely responses whether the system is at the upper or lower end of the design range
3Adaptability or versatility
If a Venturi air valve is used for self-adjustment, then the valve can self adjust for changing system conditions, but the performance comes at a higher energy operating cost
Solution Approach 1:
The patent replaces the mechanical Venturi air valve self-adjustment mechanism with a computational approach. Instead of using physical flow-restricting geometry to achieve self-adjustment, the system uses a processor to calculate dynamic nominal flow values based on sensor measurements, eliminating the need for energy-consuming mechanical adjustment components while achieving the same adaptability
Data Source
AI summary
There is described a controller and method for managing a flow unit. A measured full flow corresponding to a full open position of a flow control element of the flow unit is detected. A calibration nominal is established based on the measured full flow, and calibration relative flows are calculated based on the calibration nominal and calibration measured flows corresponding to calibration positions of the flow control element. Subsequent to calibration, an operation measured flow of the flow unit and an operation position of the flow control element are detected. A dynamic nominal is determined based on the operation measured flow and a particular calibration relative flow corresponding to the operation position of the flow control element. 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.