HVAC Airflow Priority Allocation for Multi-Zone Efficiency
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Solution Overview
Problem
Conventional multiple zone HVAC systems face inefficiencies in delivering and returning required heating or cooling capacity to rooms, especially in tight spaces that require low airflows, and existing control schemes do not effectively allocate airflow to maximize system efficiency without modifying the system's hardware.
Innovation Solution
A control method and system that allocates the maximum HVAC airflow to one zone at a time, with a predetermined minimum airflow to all other zones, utilizing enlarged duct and diffuser designs to accommodate increased airflow, and adjusts based on thermostat calls and priority, while maintaining minimum ventilation to ensure efficient energy distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If airflow is distributed to multiple zones simultaneously based on thermostat calls, then each zone can maintain its temperature independently, but system efficiency decreases and blower operating costs increase
Solution Approach 1:
The patent segments the airflow distribution by prioritizing zones in a specific sequence rather than distributing airflow simultaneously to all calling zones. The controller divides the total airflow output among zones based on priority levels, ensuring that high-priority zones receive sufficient airflow first before allocating to lower-priority zones, thereby reducing overall system energy consumption while maintaining temperature control reliability.
Solution Approach 2:
The patent changes the parameter of airflow allocation from equal or proportional distribution to priority-based sequential distribution. By adjusting the airflow parameter dynamically based on zone priority and temperature deviations, the system optimizes blower operation efficiency while ensuring critical zones maintain their setpoint temperatures.
2Productivity
If ducts and diffusers are sized to receive total HVAC output, then maximum airflow can be delivered to priority zones, but system complexity and installation difficulty increase
Solution Approach 1:
The patent introduces dynamic airflow allocation through a controller that sequentially directs total HVAC output to different zones based on priority and temperature conditions. Instead of requiring all zones to be simultaneously capable of receiving full airflow, the system dynamically switches airflow distribution, allowing ducts and diffusers to be sized for standard capacity while achieving maximum airflow delivery to priority zones through intelligent control.
3Reliability
If excess chilled or warmed air is vented out, then occupied zones receive sufficient airflow, but energy is wasted
Solution Approach 1:
The patent implements a self-regulating airflow distribution system that automatically allocates HVAC output to zones based on their current temperature deviations and priority levels. The controller continuously monitors zone conditions and directs airflow where it is most needed, eliminating the need to vent excess air and ensuring that occupied zones receive adequate airflow without energy waste.
Data Source
AI summary
Individual zone temperature control sensors in a multiple zone system are monitored by a controller, and when one zone calls, the calling zone is allocated all of the airflow from the HVAC system except for a predetermined minimum that is allocated to the other zones. If all zones have equal priority, then the airflow continues to be supplied to the first calling zone until a temperature condition is satisfied, at which time the full airflow is allocated to a second calling zone and only the predetermined minimum is supplied to the first and all other calling zones. When two or more zones having different priorities, or set point deviations, are calling at the same time, the zone with the highest priority or whose temperature is furthest from a set point will become the single zone that is open and receives all of the air except for the predetermined minimum. Air continues to be supplied to that zone until it has achieved a desired temperature, until a higher priority zone calls, or until another zone is furthest from the set point. In order to provide maximum airflow to single zones according to the method of the invention, duct and outlet sizes must be larger than is necessary for conventional systems in which more than the minimum airflow is simultaneously allocated to multiple zones. Instead of utilizing conventional duct size calculations that assume simultaneous allocation of airflow to multiple zones, the design sizes the ducts in each zone to carry 100% of the system's airflow less the predetermined minimum.