Zoned HVAC Priority Control Based on Occupancy Detection
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Solution Overview
Problem
Conventional zoned HVAC systems condition zones without regard to occupancy, leading to inefficient heating or cooling, as they distribute conditioned air at the same flow rate to both occupied and unoccupied zones, thereby increasing the time to reach desired temperatures in occupied zones.
Innovation Solution
A control system that detects occupants and their priority levels within zones, adjusting the HVAC operation to prioritize conditioned air supply to high-priority zones based on their preferred climate settings, while reducing air flow to unoccupied or low-priority zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional zoned HVAC systems distribute conditioned air at the same flow rate to all zones, then system operation is simple, but the time to reach desired temperatures in occupied zones increases and energy efficiency deteriorates
Solution Approach 1:
The system dynamically adjusts air flow rates to different zones based on real-time occupancy detection and priority levels. The controller continuously monitors occupancy status and modifies damper positions and fan speeds to prioritize occupied zones, transforming the static equal-flow distribution into a dynamic adaptive distribution that responds to changing building conditions.
Solution Approach 2:
The system applies different air flow rates and temperature settings to different zones based on their specific occupancy status and priority levels. Instead of uniform treatment, each zone receives customized conditioned air supply - high-priority occupied zones receive higher flow rates and preferred temperature settings, while unoccupied or low-priority zones receive reduced flow, creating local quality variations that optimize overall system performance.
2Loss of time
If the HVAC system prioritizes conditioned air supply to occupied zones with higher flow rates, then the time to achieve desired temperatures decreases, but the system complexity and control mechanisms increase
Solution Approach 1:
The system employs automatic occupancy detection using sensors (motion sensors, CO2 sensors, or building access system integration) that self-report occupancy status to the controller. The controller automatically translates occupancy data into appropriate air flow adjustments without requiring manual intervention or complex user input, allowing the system to self-regulate based on detected conditions while maintaining relatively simple control logic.
Solution Approach 2:
The controller serves as an intermediary that bridges occupancy detection and HVAC equipment control. It receives occupancy information from sensors, determines priority levels based on predefined criteria or user profiles, and translates these into appropriate damper positions and fan speed commands. This intermediary layer simplifies the overall system architecture by centralizing the decision-making logic and isolating the complexity within the control software rather than requiring complex hardware modifications throughout the HVAC system.
3Loss of energy
If the HVAC system conditions all zones regardless of occupancy, then uniform temperature distribution is maintained, but energy is wasted in unoccupied zones and operational costs increase
Solution Approach 1:
The system applies partial action by providing conditioned air only to the extent necessary for occupied zones. Instead of maintaining full air flow to all zones, it delivers sufficient conditioned air to occupied zones to meet their temperature requirements while significantly reducing or eliminating air flow to unoccupied zones. This partial action approach eliminates energy waste in unoccupied areas while maintaining adequate comfort in occupied areas.
Data Source
AI summary
The present disclosure relates to a heating, ventilation, and/or air conditioning (HVAC) system including a controller configured to detect a presence of an occupant in a zone of a plurality of zones. The controller is also configured to determine a priority level of the occupant and control operation of the HVAC system to prioritize supply of conditioned air to the zone of the plurality of zones over remaining zones of the plurality of zones based on the priority level of the occupant.