Hydronic system and method for operating such hydronic system
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Solution Overview
Problem
Hydronic systems face challenges in achieving optimal control accuracy and energy efficiency due to the sizing of control valves, leading to poor system control and instability, particularly with issues like excessive pressure drops and unwanted oscillations.
Innovation Solution
A hydronic system with a control valve and a valve authority determining device, connected to a feed-forward controller, which includes a frequency detector for oscillation suppression and adaptive control mechanisms to adjust valve positions and coefficients, ensuring optimal valve authority and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the control valve is undersized, then control accuracy is improved, but energy loss increases due to excessive pressure drop
Solution Approach 1:
The system dynamically adapts the valve authority by adjusting the control valve sizing or characteristics based on real-time system conditions. The feed-forward controller modifies valve parameters to maintain optimal control accuracy while minimizing energy loss, transforming a static sizing problem into a dynamic adaptation process.
Solution Approach 2:
The system changes the valve authority parameter N by adjusting control valve characteristics or sizing. The feed-forward controller modifies valve parameters (such as flow coefficient Kv) to achieve the desired balance between control accuracy and energy efficiency, directly altering system parameters to resolve the contradiction.
2Loss of energy
If the control valve is oversized, then energy loss is reduced, but control accuracy deteriorates due to insufficient valve authority
Solution Approach 1:
The system dynamically adjusts valve authority to prevent both oversizing and undersizing issues. By continuously monitoring system conditions and adapting valve parameters, the system maintains optimal control accuracy while minimizing energy loss, avoiding the pitfalls of fixed oversized valve selection.
Solution Approach 2:
The system changes valve authority parameter N by adjusting control valve characteristics to achieve optimal performance. The feed-forward controller modifies valve parameters to ensure sufficient valve authority for accurate control while preventing excessive pressure drops that would cause energy loss.
3Measurement precision
If valve authority is too high, then control accuracy is improved, but system stability deteriorates due to excessive pressure drop
Solution Approach 1:
The system uses feedback from the frequency detector to monitor oscillations and instability. When high valve authority causes instability, the feedback loop adjusts the control strategy to dampen oscillations while maintaining acceptable control accuracy, balancing the trade-off between authority and stability.
Solution Approach 2:
The system dynamically adjusts valve authority to prevent instability caused by excessive pressure drops. By adapting valve parameters in real-time based on system response, the system maintains sufficient control accuracy while avoiding the instability that arises from overly high valve authority.
4Stability of the object's composition
If valve authority is too low, then system stability is improved, but control accuracy deteriorates due to insufficient valve impact
Solution Approach 1:
The system changes valve authority parameter N by adjusting control valve characteristics to achieve the optimal balance. The feed-forward controller modifies valve parameters to ensure sufficient valve authority for accurate control while preventing instability, directly optimizing the parameter that governs both control accuracy and stability.
Solution Approach 2:
The system dynamically adapts valve authority to maintain both stability and control accuracy. By continuously adjusting valve parameters based on system conditions, the system prevents the loss of control accuracy that would result from overly low valve authority while maintaining system stability.
5Measurement precision
If feed-forward control is used, then control accuracy is improved, but system instability increases due to lack of feedback correction
Solution Approach 1:
The system merges feed-forward control with feedback correction mechanisms. The feed-forward controller provides accurate predictive control based on desired outcomes, while the feedback loop (including frequency detector) monitors actual system response and corrects deviations, combining the advantages of both control approaches to achieve accuracy and stability simultaneously.
Solution Approach 2:
The system introduces feedback correction to complement feed-forward control. The frequency detector and control system monitor oscillations and system stability, providing corrective feedback to the feed-forward controller to prevent instability while maintaining the high control accuracy provided by feed-forward prediction.
Data Source
AI summary
A hydronic system (HS) that comprises at least one hydronic circuit (HC) and a control (CT) for controlling the operation of said at least one hydronic circuit (HC) via a control path (CP), whereby said control (CT) comprises a feed forward controller (FFC). Operation of the system is improved by the hydronic system (HS) further comprising a control improvement path (CIP) running from the at least one hydronic circuit (HC) to the control (CT). Due to the control improvement path (CIP), the control (CT) can be improved in the case of the hydronic system (HS) becoming instable and/or showing poor system control.