Self-Balancing Air Fixture for Wide-Range HVAC Flow 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 control system with a multi-stage damper and orifice plate design that uses new correlations and equations to measure and control fluid flow, featuring a variable opening area controlled by nested elements and an actuator assembly, enabling precise measurement and regulation of fluid flow with a high turndown ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flow measurement devices are used, then measurement capability is provided, but cost is high and turndown ratio is limited
Solution Approach 1:
The flow control device is segmented into multiple independent components: an orifice plate for flow measurement and a multi-stage damper for flow regulation. This segmentation allows each component to be optimized independently, reducing overall system cost while maintaining measurement accuracy and extending turndown ratio capability.
Solution Approach 2:
The patent introduces an intermediary multi-stage damper between the orifice plate and the downstream system. This intermediary component enables precise flow control across a wide range without requiring complex measurement devices, thereby reducing cost while maintaining measurement and control accuracy.
2Measurement precision
If conventional flow measurement devices are used, then measurement is possible, but turndown ratio is less than 10:1
Solution Approach 1:
The damper is designed with multiple stages that can be dynamically adjusted to different positions. Each stage provides a different level of flow restriction, enabling the system to adapt to a wide range of flow conditions from high to low flow rates, thereby achieving a turndown ratio greater than 10:1 while maintaining measurement accuracy.
Solution Approach 2:
The multi-stage damper structure enables self-adjustment capabilities where the system can maintain accurate flow measurement and control across varying flow rates without requiring external intervention or complex control mechanisms, thus extending turndown ratio while preserving precision.
3Measurement precision
If HVAC systems run at minimum measurable flow, then measurement accuracy is maintained, but energy consumption increases
Solution Approach 1:
The system changes the operating parameters by enabling flow control at lower velocities and pressure differentials through the multi-stage damper. This allows the HVAC system to operate at lower flow rates while maintaining measurement accuracy, thereby reducing energy consumption without sacrificing measurement precision.
4Ease of operation
If large Total Pressure is used for flow control, then flow regulation is achieved, but energy is significantly drained
Solution Approach 1:
The flow control function is segmented into multiple stages, with each stage handling a specific portion of the flow regulation. This segmentation allows the system to achieve effective flow control at lower pressure differentials, reducing the large Total Pressure requirements and associated energy losses of conventional single-stage systems.
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 control of fluid flow with a turndown ratio greater than 10:1, reducing energy consumption, improving HVAC system efficiency, and providing better comfort in buildings by optimizing fluid flow management.
Implementation Method 1
a first sensor disposed upstream of, and a second sensor disposed downstream of, the orifice plate... determine a pressure differential based on a first pressure obtained between the first and second sensors
Implementation Method 2
The variable opening comprises a plurality of additional openings that are arranged in parallel... the inner assembly comprises a non-perforated plate or a perforated plate
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.