Low-Flow Hydronic Metering for High-Turndown HVAC Control
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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 opening area, controlled by an actuator assembly and a processor-based controller, which implements new correlations and equations to address historical contradictions in fluid flow phenomena, enabling precise measurement and control of fluid flows 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 measurement precision deteriorates for low fluid flows due to limited turndown ratio
Solution Approach 1:
The flow measurement system is segmented into multiple measurement ranges, each optimized for specific flow conditions. The device divides the overall flow range into distinct segments that can be measured with high precision, allowing accurate measurement across a wide turndown ratio from high to low flows.
Solution Approach 2:
The flow measurement device incorporates dynamic adjustment capabilities that allow it to adapt its measurement characteristics based on the current flow conditions. This dynamic behavior enables the device to maintain high measurement precision across varying flow rates by adjusting internal parameters or measurement modes.
2Measurement precision
If conventional HVAC systems operate at minimum measurable flow, then measurement accuracy is maintained, but energy consumption increases due to inability to reduce flow further
Solution Approach 1:
The system changes operational parameters by enabling flow rates below the traditional minimum measurable threshold. The high turndown ratio allows the HVAC system to operate at lower flow rates while maintaining measurement accuracy, thereby reducing energy consumption without sacrificing control precision.
3Quantity of substance
If high Total Pressure is used in current technology, then fluid flow can be maintained, but energy consumption increases significantly
Solution Approach 1:
The invention changes the pressure parameter by enabling effective fluid flow control at lower Total Pressure conditions. The improved measurement and control capability allows the system to maintain adequate flow quantities without requiring the high pressure levels that previously necessitated excessive energy input.
Data Source
AI summary
A fluid distribution apparatus that can serve as a fluid metering device that is 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 fluid distribution apparatus can operate independently or coupled with multiple like apparatuses for system 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 system, exhaust system, or a combination thereof. The fluid distribution apparatus includes fluid metering devices 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.