HVAC Valve Control with Sensor Fault Fallback Switching
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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 switches between default and fallback control modes based on sensor signal validity, using a processor to determine faulty sensor signals and adjust valve operation independently, ensuring continued energy regulation even with sensor faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fluid flow rate through the heat exchanger is increased to improve productivity, then the energy exchange capacity increases, but the efficiency of the heat exchanger is reduced
Solution Approach 1:
The valve opening is dynamically adjusted based on real-time sensor feedback to optimize fluid flow rate through the heat exchanger. The control system continuously modifies the valve position to maintain optimal flow conditions, preventing excessive flow rates that would reduce heat exchanger efficiency while still achieving high energy exchange capacity when needed.
Solution Approach 2:
Sensor signals provide continuous feedback about system parameters (such as temperature, flow rate, or pressure) to the control device. This feedback loop enables the system to automatically adjust the valve opening to maintain optimal operating conditions, resolving the contradiction between high productivity and energy efficiency by adapting to actual system state.
2Measurement precision
If the number of sensors or sensor systems is increased to improve measurement precision, then the control accuracy improves, but the risk of sensor faults increases
Solution Approach 1:
The control device is configured to detect sensor faults before they completely fail, using preliminary detection mechanisms. When a sensor fault is detected, the system proactively switches to a fallback control mode that operates independently of the faulty sensor, preventing complete system failure and maintaining reliable operation despite the presence of multiple sensors.
Solution Approach 2:
The system changes operational parameters by switching between different control modes (default mode using sensor signals vs. fallback mode operating independently of faulty sensors). This parameter change allows the system to maintain control functionality even when sensor reliability deteriorates, effectively managing the trade-off between measurement precision and reliability.
3Ease of operation
If the default control mode is used to maintain ease of operation, then the system operates simply, but the system becomes vulnerable to sensor faults
Solution Approach 1:
The control system dynamically transitions between default control mode (simple operation using sensor signals) and fallback control mode (independent operation when sensors fail). This dynamic adaptation maintains ease of operation during normal conditions while automatically providing protection against sensor faults, resolving the contradiction between simplicity and reliability.
Solution Approach 2:
The fallback control mode serves as a pre-prepared safety mechanism that cushions against the harmful effects of sensor faults. By having this alternative control mode ready in advance, the system can maintain reliable operation even when the simple default control mode becomes vulnerable due to sensor failures.
Data Source
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.