Cloud HVAC Damper Control for VAV Pressure Limits
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Solution Overview
Problem
HVAC systems with variable air volume face challenges in maintaining pressure independence and reducing noise levels, particularly when all dampers but one are closed, and existing solutions like fan with variable speed or modulating bypass damper are not always feasible, especially for retrofitting existing installations.
Innovation Solution
A cloud-based HVAC control system that uses actuator-driven valves and sensors to transmit operational parameters over a telecommunications network, calculating and adjusting damper positions and fan speeds to maintain system pressure within defined thresholds without requiring a fan with variable speed or a bypass damper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a fan with variable speed is used to control system pressure, then system pressure can be maintained within reasonable limits, but the device complexity and cost increase
Solution Approach 1:
The patent introduces a modulating bypass damper as an intermediary component that provides an alternative flow path for air to bypass the closed zones. This bypass damper acts as a mediator to maintain system pressure by allowing excess air to circulate back to the air handling unit, eliminating the need for variable speed fans while still achieving pressure control
Solution Approach 2:
The patent extracts the pressure control function from the fan and transfers it to the bypass damper. By separating the flow control function (handled by zone dampers) from the pressure control function (handled by bypass damper), the system can use simple on/off dampers in zones while maintaining pressure through the bypass mechanism
2Stress or pressure
If a modulating bypass damper is installed to maintain system pressure, then pressure control is improved, but the ease of manufacture and retrofitting capability deteriorate
Solution Approach 1:
The bypass damper is designed to perform multiple functions: it maintains system pressure, provides a recirculation path for air, and can be integrated with existing HVAC systems without requiring fundamental redesign. This multi-functionality makes it a universal solution applicable to various HVAC configurations
Solution Approach 2:
The bypass damper is pre-configured with a specific opening percentage (e.g., 20-40%) to provide immediate pressure relief when zone dampers close. This preliminary configuration allows the system to handle pressure buildup proactively rather than reactively, simplifying both installation and operation
3Manufacturing precision
If all dampers but one are closed, then zone temperature control precision is improved, but the system pressure increases excessively causing noise and mechanical damage
Solution Approach 1:
The patent converts the harmful effect of closed dampers (pressure buildup) into a beneficial circulation pattern by routing the excess air through the bypass damper back to the air handling unit. This transforms what would be a problematic pressure condition into a useful recirculation flow that maintains pressure while enabling precise zone control
Data Source
AI summary
For controlling the flow of air into the zones (Z1, Z2, Z3, Zi) of a variable air volume HVAC system (1) having actuator driven dampers (D1, D2, D3, Di), which operate in a range from a minimum damper position to a maximum damper position for adjusting the flow of air into a zone (Z1, Z2, Z3, Zi), flow measurement values and current damper positions are transmitted via a telecommunications network (2) to a cloud-based HVAC control center (3). Using the flow measurement values and calibration values, which indicate HVAC system parameters at a defined calibration pressure in the HVAC system (1) and at different damper positions, the cloud-based HVAC control center (3) calculates the minimum damper position for the actuators (A1, A2, A3, Ai), such that the pressure in the HVAC system (1) does not exceed a defined maximum pressure threshold, and transmits the minimum damper position to the actuators.