Flow Rate Estimation Using Differential Pressure and Regression Models
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Solution Overview
Problem
Conventional flow rate measurement methods in HVAC systems are expensive, inaccurate, and difficult to calibrate, with high uncertainty, necessitating a more reliable and cost-effective approach to determine fluid flow rates through HVAC devices.
Innovation Solution
A system and method that utilize pressure sensors to measure pressure differentials across HVAC devices, combined with a regression model trainer to generate coefficients for estimating flow rates based on these measurements, allowing for the estimation of flow rates through tested or untested devices with similar characteristics, and an uncertainty calculator to determine the accuracy of these estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow rate sensor is installed to measure flow rate directly, then measurement accuracy is improved, but system cost and complexity increase
Solution Approach 1:
The patent uses differential pressure sensors as intermediary devices to indirectly measure flow rate through pressure differential measurements across the HVAC device. This mediator approach avoids direct flow rate sensing while providing sufficient measurement accuracy for control purposes.
Solution Approach 2:
The patent replaces mechanical flow rate sensors with a combination of differential pressure sensors and computational algorithms. The system substitutes direct mechanical measurement with indirect pressure-based measurement combined with mathematical modeling and regression analysis.
2Reliability
If conventional flow rate sensors are used, then flow rate data is obtained, but measurement uncertainty is high and calibration is difficult
Solution Approach 1:
The system performs self-calibration by using the HVAC device itself as the measurement reference. The differential pressure measurements and flow rate data are used together to automatically generate device-specific regression coefficients, eliminating the need for external calibration equipment or procedures.
Solution Approach 2:
The patent transforms the measurement approach by changing from direct flow rate sensing to pressure differential measurement with computational conversion. This parameter transformation allows the system to exploit the more stable and easier-to-measure pressure differential while deriving flow rate information through mathematical relationships.
3Ease of manufacture
If pressure sensors are used to estimate flow rate, then system cost is reduced, but measurement precision may be compromised
Solution Approach 1:
The system performs preliminary characterization during manufacturing or commissioning by collecting paired pressure differential and flow rate measurements. This preliminary action generates device-specific regression coefficients that are stored for later use, enabling accurate flow rate estimation without requiring expensive flow rate sensors during operation.
Solution Approach 2:
The patent creates a computational model (regression equation) that copies the flow-rate-to-pressure relationship specific to each HVAC device. This copied relationship allows the system to estimate flow rate from pressure measurements with high accuracy, matching the performance of direct flow rate sensing at lower cost.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides accurate and cost-effective estimation of flow rates through HVAC devices, reducing the need for expensive sensors and improving measurement reliability by using differential pressure measurements to predict flow rates with associated uncertainties.
Implementation Method 1
one or more pressure sensors configured to measure a plurality of pressure differentials across a tested device
Data Source
AI summary
Systems and methods for estimating a flow rate through a device are provided. One or more pressure sensors measure a plurality of pressure differentials across a tested device. A temporary flow rate sensor measures a plurality of flow rates through the tested device. Each of the measured flow rates corresponds to one of the measured pressure differentials. A regression model trainer generates regression coefficients for a flow rate model using the measured pressure differentials and corresponding flow rates. A flow rate estimator uses the flow rate model to estimate a flow rate through a tested or untested device as a function of a measured pressure differential across the tested or untested device.