HVAC Valve Control with Sensor Fault Detection and Fallback Mode

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Solution Overview

Problem

HVAC systems face reduced efficiency and increased risk of sensor faults due to high fluid flow rates and complex sensor systems, which affect the accuracy of energy exchange regulation in heat exchangers.

Innovation Solution

A method and device for controlling the opening of a valve in an HVAC system that uses a default control mode based on a default sensor signal, with a fallback control mode activated when the default sensor signal is faulty, allowing the system to maintain operation independently of faulty sensor signals and dynamically switch back to the default mode when the sensors become valid again.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of sensors or sensor systems is increased to improve measurement precision, then the reliability of the HVAC system decreases due to increased risk of sensor faults

Engineering Contradiction:
Improvesensor measurement precisionVSAvoidsystem reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a fallback control mode that is prepared in advance to compensate for sensor faults. When a sensor fault is detected, the system automatically switches to the fallback control mode, which maintains HVAC operation using alternative control strategies. This beforehand cushioning ensures that sensor failures do not lead to system shutdown, thereby maintaining reliability while allowing the use of multiple sensors for improved measurement precision.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Measurement precision

If complex sensor systems are used to improve measurement precision, then the difficulty of detecting and measuring sensor faults increases

Engineering Contradiction:
Improvesensor measurement precisionVSAvoidsensor fault detection difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent employs a sensor fault detection mechanism that continuously monitors sensor signals and provides feedback on their validity. The control unit evaluates whether sensor signals are faulty and automatically switches between default and fallback control modes based on this feedback. This structured feedback approach simplifies the detection of sensor faults in complex sensor systems by providing clear criteria for fault identification and automatic response.

Inventive Principle:
Principle #23Feedback

3Productivity

If the valve opening is controlled continuously to regulate fluid flow precisely, then the system complexity increases requiring more sophisticated sensor systems

Engineering Contradiction:
Improveenergy exchange regulation precisionVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a dynamic control mode switching mechanism that adapts the control strategy based on sensor availability. The system dynamically transitions between the default control mode (with precise continuous valve control) and the fallback control mode (with simplified control). This dynamic adaptation allows the system to maintain precise energy exchange regulation when sensors are functional while reducing complexity automatically when sensor faults occur, avoiding the need for permanently complex control systems.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2896899B1Valve control in an HVAC system with sensors
Publication Date: 2017.05.24 BELIMO HOLDING AG
  • EP2896899B1 patent drawingFigure 1
  • EP2896899B1 patent drawingFigure 2
  • EP2896899B1 patent drawingFigure 3

AI summary

The present disclosure is directed towards a method of controlling opening of a valve (10) in an HVAC system (100). The method includes controlling the opening of the valve (10) according to a default control mode in dependence of a default sensor signal. The method further includes determining, while controlling the opening of the valve (10) according to the default control mode, whether the default sensor signal is faulty and switching, in case of the default sensor signal being faulty, to controlling the opening of the valve (10) according to a fallback control mode, with the opening of the valve (10) being controlled independently of the faulty sensor signal in the fallback control mode. The present invention is further directed towards a corresponding control device opening of a valve (10) in an HVAC system as well as a corresponding computer program product.