HVAC self-balancing components and controls
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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 using a multi-stage damper with a variable orifice plate and actuator assembly, which includes a processor-controlled controller to determine flow rates based on pressure differentials and flow coefficients, enabling precise measurement and control of fluid flows across a wide range.
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 patent replaces conventional mechanical flow measurement devices with a differential pressure-based measurement system using a simple orifice plate and pressure sensors. This substitution eliminates complex mechanical moving parts while achieving accurate flow measurement through pressure differential detection, thereby reducing device complexity and cost while maintaining measurement precision.
Solution Approach 2:
The patent uses a simplified model of flow measurement based on differential pressure principles that replicates the functionality of complex flow meters. By measuring pressure drop across an orifice and calculating flow rate using established fluid dynamics equations, the system creates a functional copy of sophisticated flow measurement capabilities using inexpensive components.
2Measurement precision
If conventional flow measurement devices with limited turndown ratio are used, then measurement is possible at certain flow rates, but accurate measurement of low fluid flows cannot be achieved
Solution Approach 1:
The patent implements a dynamic measurement system where the differential pressure measurement approach remains valid across a wide range of flow conditions. The system adapts to varying flow rates by maintaining sensitivity to pressure differentials, enabling accurate measurement from very low flows to high flows through a single device configuration, achieving high turndown ratio capability.
Solution Approach 2:
The patent changes the measurement parameter from direct flow measurement to differential pressure measurement. This parameter transformation allows the system to detect very small pressure differences corresponding to low flow rates while also handling large pressure differences at high flow rates, thereby extending the measurable flow range and achieving high turndown ratio.
3Measurement precision
If HVAC systems run at higher flows to ensure measurable performance, then measurement and control accuracy is maintained, but energy consumption increases
Solution Approach 1:
The patent implements a feedback control system using differential pressure sensors to continuously monitor actual flow rates and provide real-time feedback to the control system. This enables precise flow control at any operating point, allowing the HVAC system to operate at lower, more energy-efficient flows while maintaining measurement and control accuracy through active feedback adjustment.
Solution Approach 2:
The patent replaces energy-intensive mechanical flow control methods with a differential pressure-based control system that uses electronic sensors and control algorithms. This substitution enables precise flow control without the energy penalties of mechanical throttling devices, allowing optimal energy efficiency while maintaining control accuracy.
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 achieves high turndown ratios, reducing energy consumption, improving HVAC system efficiency, and enabling precise control of fluid flows, thereby enhancing comfort and compliance with energy standards.
Implementation Method 1
determine a pressure differential across the orifice plate based on a first pressure sensed upstream of, and a second pressure sensed downstream of, the orifice plate
Data Source
AI summary
An intelligent self-balancing downstream device (e.g., air fixture or diffuser) that can obtain accurate flow measurements that can be used to perform the self-balancing in situ and during operation to satisfy a set point. The downstream device may be controllable by a single software system or network accessible locally on site or remotely off site. The downstream device can operate in a single zone or be coupled with multiple like apparatuses for multi-zone operation. It is a high turndown ratio and self-balances, which can allow 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 downstream device can include 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.