Passive Airflow Damper Control for Stable Zone Ventilation
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Solution Overview
Problem
Existing central ventilation systems face challenges in efficiently controlling airflow to specific zones, leading to excessive energy consumption and poor indoor air quality due to fluctuations in duct air pressure and inadequate ventilation, as previous methods were ineffective and costly in managing airflow rates.
Innovation Solution
A ventilation terminal system with an integral primary zone-controlled damper and pressure-independent flow control device that regulates airflow using system duct pressure, eliminating the need for direct power sources and allowing for constant airflow regulation, even in the absence of primary power, and can be easily maintained and mounted in various structural configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If terminal devices are opened and closed to limit ventilation to occupied areas, then energy consumption is reduced, but duct air pressure fluctuates causing uneven air distribution across zones
Solution Approach 1:
The system changes the parameter of airflow resistance dynamically by adjusting damper positions in response to pressure changes. When pressure increases in a zone, the damper automatically closes partially to reduce airflow; when pressure decreases, the damper opens to increase airflow. This maintains stable air distribution while allowing terminal devices to be closed for energy savings.
Solution Approach 2:
The system uses pressure-sensitive dampers that automatically sense duct air pressure changes and adjust their position accordingly. This feedback mechanism ensures that when terminals are closed to save energy, the pressure changes are compensated by damper adjustment, maintaining stable air distribution to occupied zones without requiring active control systems.
2Ease of operation
If VAV terminals with electrically powered control devices are used to control airflow at each zone, then airflow regulation capability is improved, but device complexity and power source requirements increase
Solution Approach 1:
The system employs passive pressure-sensitive dampers that automatically regulate airflow based on duct pressure without requiring external power sources, control electronics, or complex actuation mechanisms. The dampers self-adjust their position in response to pressure changes, eliminating the need for motors, sensors, and control circuits while maintaining effective airflow regulation at each zone.
Solution Approach 2:
The invention replaces complex electrical-mechanical VAV terminal systems with a purely mechanical pressure-sensitive damper system. Instead of using electric motors, electronic sensors, and control algorithms to regulate airflow, the system uses the natural mechanical response of pressure-sensitive dampers to duct pressure changes, significantly simplifying the device while maintaining regulation capability.
3Productivity
If central fan speed is controlled to prevent over or under-ventilation, then overall ventilation balance is improved, but airflow amounts at each zone branched duct remain inconsistent
Solution Approach 1:
The system divides the central ventilation control into two levels: (1) central fan speed control to maintain overall ventilation balance and efficiency, and (2) individual zone damper control to maintain consistent airflow at each branched duct. The pressure-sensitive dampers at each zone independently adjust to compensate for pressure changes, ensuring consistent airflow distribution while the central fan operates at optimized speed for overall system productivity.
4Device complexity
If fixed inlet terminals are used in fan assisted central exhaust systems, then system simplicity is maintained, but excessive energy is consumed by removing air from areas that do not require ventilation
Solution Approach 1:
The system transitions from static fixed inlet terminals to a dynamic configuration where pressure-sensitive dampers automatically adjust their opening based on duct pressure and terminal position. When terminals in unoccupied areas are closed, the dampers in occupied zones dynamically adjust to maintain proper airflow, allowing the system to maintain simplicity while reducing energy consumption by preventing air removal from areas that do not require ventilation.
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 effectively regulates airflow to predetermined levels, reducing energy consumption by optimizing fan requirements and maintaining consistent indoor air quality across zones, while minimizing maintenance needs and allowing for flexible installation.
Implementation Method 1
a pressure independent flow control device that is integral to the primary flow control, which in one embodiment may be a damper
Data Source
AI summary
A system and method for providing a substantially constant volume exhaust or ventilation air terminal system is shown for controlling exhaust and/or return airflow rates in a system having a central fan or ventilator. The system and method permits zone-by-zone or area-by-area airflow regulation or control in non-demand areas in response to a demand or call for ventilation in demand areas. In one embodiment, the system employs at least one constant airflow controller or regulator situated in a damper. Another embodiment shows a combination of a first constant airflow controller or regulator situated or mounted on a damper with a second constant airflow controller or regulator situated in a duct associated with the damper. In still another embodiment, a constant airflow controller or regulator is provided in a duct, and used in combination with a solid damper.