Variable Orifice Plate Flow Control for High Turndown HVAC
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Solution Overview
Problem
Current fluid flow measurement devices in HVAC systems are expensive and have limited turndown ratios, making them ineffective for accurately measuring low fluid flows, leading to energy inefficiencies and reduced comfort in buildings.
Innovation Solution
A flow device with a multi-stage damper and orifice plate system that uses advanced formulas and actuator assemblies to provide a high turndown ratio, enabling precise measurement and control of fluid flows through a heating, ventilation, and air conditioning (HVAC) system, incorporating a controller to regulate the flow based on pressure differentials and actuator positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flow measurement devices are used in HVAC systems, then measurement capability is provided, but the devices are expensive and have limited turndown ratios, making them ineffective for accurately measuring low fluid flows
Solution Approach 1:
The flow control device is divided into multiple independent stages, each with its own damper and control mechanism. This segmentation allows each stage to operate independently within its optimal range, enabling the overall system to achieve a high turndown ratio by combining the output of multiple stages, thereby resolving the contradiction between measurement precision and adaptability across different flow rates
Solution Approach 2:
The invention employs dynamically adjustable dampers that can change their opening positions continuously to adapt to varying flow requirements. This dynamic adjustment capability allows the system to maintain accurate flow measurement and control across a wide turndown ratio, transforming a static measurement device into an adaptive system that responds to changing operational conditions
2Productivity
If conventional flow measurement devices are used, then basic flow control is achieved, but energy consumption increases due to inability to accurately measure and regulate low fluid flows
Solution Approach 1:
The system incorporates feedback mechanisms where flow sensors continuously monitor actual flow rates and send signals to the control system. The controller adjusts damper positions based on this feedback to maintain the desired flow rate, preventing energy waste from over-flow conditions and ensuring optimal system efficiency across all operating points, thereby resolving the contradiction between productivity and energy consumption
3Measurement precision
If multi-stage damper system is implemented, then high turndown ratio and accurate measurement is achieved, but device complexity increases
Solution Approach 1:
The invention merges multiple functional elements into an integrated multi-stage damper assembly where several dampers are positioned in series within a single housing. This consolidation approach achieves high measurement precision and turndown ratio while minimizing the space and components required, effectively managing device complexity through thoughtful integration rather than simple addition of parts
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 solution allows for accurate measurement and control of fluid flows with a high turndown ratio, reducing energy consumption and enhancing comfort in buildings by providing precise air and fluid volume control, while also simplifying HVAC system designs and reducing manufacturing costs.
Implementation Method 1
determine a pressure differential based on a first pressure measurement obtained by a first sensor
Implementation Method 2
regulate the variable opening based on the pressure differential and the position of the outer and inner assemblies
Data Source
Figure 1~2A
Figure 2B~2D
Figure 2E~2F
AI summary
Systems and methods for measuring and controlling fluid flow include an orifice plate defining a variable opening. The orifice plate includes an outer assembly comprising a central opening and an inner assembly extending through the central opening. The flow device regulates high and very low volumes of fluid with precision, inexpensively, with superior acoustics, reduced energy, and simpler design. The high turndown device permits use at lower velocities, thereby reducing noise generation and eliminating need for sound-attenuating liners. The high rangeability device combines several part numbers into fewer parts, thereby streamlining product portfolios. In some cases, cost benefits associated with the flow device allow equipment to be scaled back 100:1 rather than 10:1, providing energy savings, fewer product variations, simple and more robust applications. The device meets new and old building fresh air, comfort and energy codes. The flow device can be engineered, selected, and sized without sophisticated software programs.