Multi-Zone HVAC Terminal with Rotating Dampers to Reduce Reheat Energy
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Solution Overview
Problem
Existing HVAC systems face inefficiencies in energy consumption and complexity due to separate zones requiring individual control, leading to unnecessary ventilation and increased costs, especially when occupancy varies and different zones have distinct temperature and ventilation needs.
Innovation Solution
A variable air flow/multiple zone HVAC air terminal system with a dual path control damper arrangement and bypass feature, allowing for precise control of air flow and ventilation in each zone, using rotating air dampeners and a controller to adjust air flow based on sensed conditions, reducing energy consumption and simplifying operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate HVAC control equipment is installed for each zone, then precise zone-level temperature and ventilation control is achieved, but device complexity and capital costs increase
Solution Approach 1:
The patent combines multiple zone control functions into a single HVAC terminal unit. The device integrates multiple dampers (conditioned air damper, bypass damper, outside air damper) and multiple heat exchangers (first and second heat exchangers) into one unified terminal, allowing precise control of multiple zones without requiring separate equipment for each zone. This merging approach maintains zone-level control precision while reducing overall system complexity and capital costs.
Solution Approach 2:
The HVAC terminal unit is designed as a multi-functional device that can simultaneously serve multiple zones with different heating and cooling requirements. The unit can independently control conditioned air flow, bypass air flow, and outside air flow to different zones, making a single device perform the work of multiple separate units while reducing device complexity.
2Adaptability or versatility
If outside air ratio is increased to meet ventilation requirements for high occupancy zones, then ventilation needs are satisfied, but energy consumption for conditioning ventilation air increases
Solution Approach 1:
The patent implements local quality control by allowing different outside air ratios for different zones based on their specific occupancy and ventilation needs. The outside air damper can be independently controlled to supply appropriate amounts of outside air to zones requiring ventilation while limiting outside air to zones that do not need it, thereby satisfying ventilation requirements for high occupancy zones without unnecessarily increasing energy consumption for conditioning ventilation air in other zones.
Solution Approach 2:
The system dynamically adjusts the outside air ratio based on real-time zone conditions. The controller continuously monitors zone occupancy and ventilation requirements, then dynamically modulates the outside air damper to optimize the balance between satisfying ventilation needs and minimizing energy consumption for conditioning outside air.
3Productivity
If fan operates at full capacity to meet peak air flow demand, then all zones receive required airflow, but energy consumption increases when full airflow is not needed
Solution Approach 1:
The patent employs dynamic fan control where the fan operates at variable speeds based on actual system demand. The controller monitors the airflow requirements of connected zones and dynamically adjusts fan speed accordingly. When peak airflow is needed, the fan operates at full capacity; when zones require less airflow, the fan speed is reduced, thereby maintaining productivity capability while significantly reducing fan energy consumption during part-load conditions.
Solution Approach 2:
The system incorporates feedback control where the controller continuously monitors zone conditions and airflow demands, then uses this information to adjust fan operation. The feedback mechanism ensures the fan delivers the precise airflow needed for current conditions rather than operating continuously at full capacity, optimizing the balance between productivity and energy consumption.
4Temperature
If conditioned air is supplied to all zones, then temperature control is maintained, but reheat energy requirements increase when zones need less heating or cooling
Solution Approach 1:
The patent applies local quality control by providing different air temperatures to different zones based on their specific heating and cooling needs. The first heat exchanger can be configured to provide heated air to zones requiring heating while the second heat exchanger provides cooled air to zones requiring cooling. This eliminates the need to supply uniformly conditioned air to all zones and then reheat or recool it, thereby maintaining temperature control while significantly reducing reheat energy losses.
Solution Approach 2:
The system changes the temperature parameter of supplied air based on zone requirements. Rather than supplying air at a fixed temperature that requires reconditioning in each zone, the system dynamically adjusts the supply air temperature parameters to match zone needs, eliminating reheat energy losses while maintaining precise temperature control.
Data Source
AI summary
A variable air flow/multiple zone HVAC air terminal system has a plurality of air passageways for conditioned air, bypass air, and optionally outside air, for separate distribution to outlet passageways to the multiple zones. A corresponding plurality of rotating cylindrical air dampeners selectively controls air flow from the conditioned air, bypass air, and outside air passageways to respective ones of the plurality of outlet air passageways corresponding to respective zones. Damper drivers cause rotation of the rotating air dampeners in response to sensed air conditions in the respective zones to control ratios and volume flow rates of the conditioned, bypass, and outside air fed to the respective outlet air passageways, so rotation of respective ones of the rotating air dampers selectively varies air flow to the respective outlet air passageways.