Heat Exchanger Valve Flow Limiting Using Dynamic Maximum Rate Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
HVAC systems face challenges in maintaining adequate flow through heat exchangers due to varying hydraulic resistances over time, leading to excessive flow and wear on valve components, as existing solutions rely on static default flow rates that do not account for transient changes.
Innovation Solution
A dynamic maximum flow setting method is implemented, using a valve controller that reads flow sensor signals, applies moving averages, bounds values within thresholds, and uses a maximum filter to determine and limit the flow rate, allowing for real-time adjustments to prevent excessive flow and adapt to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a static default flow rate is used for valve control, then the valve position can be determined after design stage, but the flow becomes excessive when hydraulic resistances change over time, causing wear on valve components
Solution Approach 1:
The patent applies dynamics by transitioning from a static default flow rate to a dynamic maximum flow rate that changes over time. The controller continuously updates the maximum flow rate based on monitored actual flow rates, allowing the valve control to adapt to changing hydraulic resistances while preventing excessive flow that would cause component wear
Solution Approach 2:
The patent implements feedback by monitoring the actual flow rate through a flow sensor and using this information to update the maximum flow rate. The controller compares the actual flow rate with the maximum flow rate and adjusts the valve position accordingly, creating a closed-loop control system that prevents excessive flow and extends valve component life
2Ease of operation
If valve positions are determined using default flow rates, then control can be implemented after design stage, but transient changes cause excessive flow leading to power waste
Solution Approach 1:
The system uses feedback from flow sensors to continuously monitor actual flow rates and update the maximum flow rate accordingly. This allows the valve to respond to transient changes in real-time, preventing excessive flow conditions that would waste power while maintaining the ability to operate after the design stage
Solution Approach 2:
The patent transitions from static valve positioning based on default flow rates to dynamic valve control where the maximum flow rate is continuously updated based on monitored actual flow rates. This dynamic adjustment prevents power waste during transient conditions while maintaining post-design operational capability
3Productivity
If higher flow rates are allowed through heat exchangers, then heating/cooling demand can be met, but valve wear increases and operational lifetime decreases
Solution Approach 1:
The controller continuously monitors the actual flow rate through the heat exchanger and uses this feedback to adjust the valve position. By maintaining flow rates at or below the dynamically updated maximum, the system ensures adequate heating/cooling performance while preventing excessive flow that would accelerate valve wear and extend operational lifetime
Solution Approach 2:
The patent changes the flow rate parameter dynamically by updating the maximum flow rate based on monitored actual flow rates. This parameter adjustment allows the system to optimize between productivity and valve lifetime by adapting the flow rate to current operating conditions rather than using a fixed default value
Data Source
AI summary
Maximum flow setting. A method of limiting flow through a valve (1) comprising: reading a time series of signals from a flow sensor (5a, 5b); producing a time series of flow rates from the time series of signals; producing an averaged series of values; producing a first bounded series of values by replacing values that are below a lower threshold (13) with the lower threshold (13); producing a second bounded series of values by replacing values that exceed an upper threshold (15) with values that equal the upper threshold (15); producing a maximum flow rate by applying a moving maximum filter (17) to the second bounded series; reading a set point signal (9); limiting the set point signal (9) to the maximum flow rate; producing an actuation signal from the limited set point signal; transmitting the actuation signal to an actuator (7).