Detecting HVAC Control Loop Interactions via Disturbance Analysis
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Solution Overview
Problem
In building automation systems, control loop interactions between HVAC devices can lead to oscillations and performance deterioration, causing energy inefficiencies, comfort issues, and wear and tear, due to unintentional influences between adjacent zones or devices.
Innovation Solution
A computerized method and system for detecting control loop interactions by storing and analyzing historical disturbance data from multiple control loops, calculating a measure of interaction, and determining whether a loop interaction exists, allowing for corrective measures to be taken.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple control loops operate in adjacent zones without interaction detection, then each loop can independently control its zone, but control loop interactions cause oscillations and performance deterioration
Solution Approach 1:
The system implements feedback by monitoring control loop disturbances and using this information to detect interactions between adjacent zones. The feedback mechanism compares disturbance patterns across multiple zones to identify when control loops are interfering with each other, enabling corrective actions to maintain stability without increasing physical system complexity
Solution Approach 2:
The patent introduces an intermediary detection system that acts as a mediator between multiple independent control loops. This intermediary monitors disturbance patterns and identifies interactions without requiring direct modification of the individual control loops, thus maintaining their independence while preventing harmful interactions
2Loss of energy
If control loop interactions are not detected, then the system operates with simpler monitoring, but energy inefficiencies and wear and tear increase
Solution Approach 1:
The control loops perform self-diagnosis by monitoring their own disturbance patterns and comparing them with adjacent zones. Each control loop contributes its disturbance data to the interaction detection process, and the system uses this self-reported information to identify interactions that cause energy inefficiency, eliminating the need for external monitoring infrastructure
Solution Approach 2:
The patent replaces physical monitoring equipment with a software-based disturbance analysis system. Instead of using additional sensors or mechanical monitoring devices to detect interactions, the system substitutes a computational approach that analyzes control loop disturbance patterns digitally, reducing hardware complexity while improving energy efficiency
3Productivity
If control loop interactions occur, then adjacent zones can be controlled independently, but oscillations and performance deterioration result
Solution Approach 1:
The system performs preliminary detection of potential interactions by monitoring disturbance patterns before they develop into harmful oscillations. By identifying interaction trends early in the disturbance analysis process, the system can take preventive corrective actions to maintain performance and prevent stability deterioration before they occur
Data Source
AI summary
A system for detecting a control loop interaction between two or more control loops. The system includes a processing circuit configured to store a history of detected loop disturbances for a plurality of control loops. The processing circuit is also configured to compute a measure of interaction between control loops using the history of detected loop disturbances. The processing circuit is further configured to determine whether a loop interaction exists based on the computed measure of interaction.