Multi-Stage Airflow Controller for Low-Flow HVAC Measurement
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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, leading to inefficient HVAC systems that consume excess energy and fail to provide comfort in buildings.
Innovation Solution
A fluid flow measurement and control system with a multi-stage damper and orifice plate design that uses new correlations and equations to address contradictions in fluid flow phenomena, enabling precise measurement and control of fluid flows with a high turndown ratio, reducing energy consumption, and improving HVAC system efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flow measurement devices are used, then measurement capability is provided, but cost is prohibitively expensive and turndown ratio is limited
Solution Approach 1:
The flow controller is divided into multiple functional segments: a flow sensor for detection, a control valve for regulation, and a control algorithm for processing. This segmentation allows each component to be optimized independently, reducing overall system cost while maintaining measurement precision through specialized low-cost sensors and electronic control rather than mechanical measurement mechanisms
Solution Approach 2:
The patent replaces traditional mechanical flow measurement devices with an electronic control system comprising a flow sensor, control valve, and control algorithm. This substitution eliminates complex mechanical measurement mechanisms, significantly reducing device cost while maintaining or improving measurement accuracy through electronic sensing and digital processing
2Measurement precision
If conventional flow measurement devices are used, then measurement capability is provided, but turndown ratio is limited to less than 10:1
Solution Approach 1:
The control valve is designed with dynamic adjustment capability allowing continuous modulation of the flow passage area.配合the control algorithm, this enables the system to adapt to a wide range of flow conditions, achieving a high turndown ratio by dynamically adjusting valve opening from fully closed to fully open positions based on real-time flow sensor feedback
Solution Approach 2:
The system implements a closed-loop feedback control mechanism where the flow sensor continuously monitors actual flow, the control algorithm compares it with the setpoint, and the control valve adjusts accordingly. This feedback mechanism enables precise control across a wide turndown ratio by automatically adapting to varying flow conditions and maintaining measurement accuracy throughout the entire operating range
3Reliability
If HVAC systems run at higher flows to maintain measurement accuracy, then measurement reliability is improved, but energy consumption increases
Solution Approach 1:
The closed-loop feedback control allows the HVAC system to operate at the minimum necessary flow rate while maintaining measurement reliability. The flow sensor continuously monitors actual flow, and the control algorithm adjusts the control valve to maintain optimal flow conditions for accurate measurement, preventing both over-flow (wasting energy) and under-flow (compromising measurement reliability)
Solution Approach 2:
The system dynamically changes operating parameters (flow rate, valve opening position) based on real-time conditions to maintain measurement reliability. By adjusting these parameters optimally, the system ensures accurate measurement at the lowest possible energy consumption level, rather than operating at fixed high flow rates
4Measurement precision
If large Total Pressure is used in current technology, then flow measurement capability is maintained, but energy consumption is significantly drained
Solution Approach 1:
The patent replaces traditional pressure-based mechanical measurement systems with an electronic flow sensor and control valve system. This substitution eliminates the need to generate and maintain large total pressure differentials for measurement, significantly reducing energy consumption while maintaining or improving measurement precision through electronic sensing technologies
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
The system allows for accurate measurement and regulation of fluid flows with a high turndown ratio, reducing energy consumption and enhancing HVAC system efficiency, enabling precise control and comfort in buildings while minimizing the need for multiple device sizes and sound-attenuating components.
Implementation Method 1
determine a pressure differential based on a first pressure obtained between the first and second sensors
Implementation Method 2
A multi-stage damper can be used to address limitations of a standard butterfly damper... the projection of the inner annulus opening A0 normal to the faces of the annulus and opening disk itself
Data Source
AI summary
An air distribution apparatus that serves as a single sensing device for both lighting, LiFi, and HVAC functions that are operable on a single platform by building automation systems. The building automation system may be controllable by a single software system or network accessible locally on site or remotely off site. The air distribution apparatus can operate in a single zone or coupled with multiple like apparatuses for multi-zone operation. It is a high turndown, self-balancing system which allows for continuous commissioning with built-in fault diagnostic systems and that may be used as a supply, return, or exhaust system, or a combination thereof. The air distribution apparatus includes multi-stage airflow control systems that operate progressively based on unique actuation mechanisms and/or algorithms that allow for precise flow control and feedback to self-balance and commission the system.