Remote Flow Device Calibration for Low-Flow HVAC Accuracy
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Solution Overview
Problem
Current fluid flow measurement devices are expensive and have limited turndown ratios, making them ineffective for accurately measuring low fluid flows, particularly in HVAC systems, leading to energy inefficiency and discomfort due to high energy consumption.
Innovation Solution
A fluid flow measurement and control system with a multi-stage damper and orifice plate design that uses Flow and Discharge Coefficient Equations to address contradictions in fluid flow phenomena, enabling precise measurement and control of low fluid flows with a high turndown ratio, reducing energy consumption and improving comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional fluid flow measurement devices are used, then measurement capability is provided, but cost is high and turndown ratio is limited
Solution Approach 1:
The measurement system is segmented into multiple discrete calibration points rather than requiring continuous calibration across the entire measurement range. The device uses a lookup table storing flow coefficients at specific discrete flow rates, allowing accurate measurement through interpolation between these points. This segmentation reduces calibration complexity while maintaining measurement precision across a wide turndown ratio.
Solution Approach 2:
The system changes the parameter being measured from direct differential pressure to flow coefficient derived from discrete calibration points. By pre-calculating and storing flow coefficients at various discrete flow rates in a lookup table, the system transforms the measurement approach to achieve high precision without complex real-time calculations or continuous calibration procedures.
2Measurement precision
If traditional fluid flow measurement devices are used, then measurement capability is provided, but cost is prohibitive
Solution Approach 1:
Instead of using expensive specialized measurement hardware for each application, the system creates a computational model (lookup table) that copies the calibration data from a master reference. This digital copy allows multiple devices to share the same calibration information, significantly reducing manufacturing costs while maintaining measurement precision for low fluid flows.
Solution Approach 2:
The system replaces expensive, complex measurement devices with simpler, cheaper components including basic differential pressure sensors and computational algorithms. The lookup table approach uses inexpensive stored data rather than expensive real-time calibration hardware, making the system economically viable while achieving accurate low flow measurement.
3Measurement precision
If large Total Pressure is used in current technology, then measurement capability is maintained, but energy consumption increases
Solution Approach 1:
The system changes the measurement parameter from large total pressure differential to small differential pressure measurements combined with flow coefficient lookup. By using pre-calculated flow coefficients that account for the relationship between pressure differential and flow rate, the system can accurately measure low flows without requiring large pressure differentials, thereby reducing energy consumption in HVAC systems.
Data Source
AI summary
A method/structure for remotely calibrating a product fluid flow device having one or more apertures with aggregate area Ao, where fluid flows along a fluid flow path therethrough in response to pressure differentials ΔP across the apertures. Calibration can occur on a calibration device to determine a fluid flow profile for a product device. In response to a determination that the product device is installed according to a different arrangement than used during calibration, the flow profile can be updated according to the different arrangement and provided to the product device in situ.