Occupancy Detection Using Motion and People Count Sensing
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Solution Overview
Problem
Existing occupancy detection systems, such as PIR sensors, often inaccurately report occupancy status in spaces like hotel guestrooms, leading to dissatisfaction due to incorrect control of comfort conditions and excessive energy usage, as they fail to detect motion in areas like bathrooms and may not account for people who are asleep.
Innovation Solution
A system combining a motion sensor and a person sensor to determine occupancy by tracking people count, using a controller to differentiate between occupied and unoccupied states based on motion detection and people count, without relying on cameras, allowing for accurate control of building components like HVAC systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a PIR motion sensor is used to detect occupancy, then the system can control building components based on motion detection, but the occupancy detection accuracy deteriorates because the sensor fails to detect motion in areas like bathrooms and when people are asleep
Solution Approach 1:
The system divides the space into multiple zones with separate motion sensors positioned to cover different areas (e.g., living area, bathroom, bedroom). Each sensor monitors its specific zone, and the controller integrates data from all zones to determine overall occupancy status, ensuring comprehensive coverage without blind spots.
Solution Approach 2:
The system transitions from relying solely on motion detection (spatial dimension) to incorporating people count information (quantitative dimension). By combining motion sensor data with people sensor data at doorways, the system creates a multi-dimensional occupancy assessment that resolves ambiguities in motion-only detection.
2Reliability
If a motion sensor is used to detect occupancy, then the system can determine occupancy status, but energy savings deteriorate because the system cannot reliably distinguish between occupied and unoccupied states
Solution Approach 1:
The system implements feedback loops where the controller continuously monitors motion sensor outputs and adjusts building component operation accordingly. When motion is detected in any zone, the system maintains comfortable conditions; when no motion is detected across all zones for a predetermined period, the system transitions to energy-saving mode, creating responsive feedback-based energy management.
Solution Approach 2:
The system uses people sensors at doorways to detect entry/exit events before the occupants fully enter or leave the space. This preliminary detection allows the controller to anticipate occupancy changes and adjust building components proactively, ensuring comfortable conditions are maintained just in time while avoiding unnecessary energy consumption.
3Measurement precision
If traditional sensors are used for occupancy detection, then the system can monitor space usage, but privacy protection deteriorates because cameras would be required for accurate detection
Solution Approach 1:
The system replaces camera-based optical detection with non-optical sensing methods including PIR motion sensors that detect thermal radiation and people sensors that detect presence through doorways. These sensors provide sufficient occupancy information without capturing visual images, thereby maintaining privacy while achieving reliable detection precision.
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
This approach enhances the accuracy of occupancy detection, ensuring comfort when occupied and energy savings when unoccupied, while respecting privacy, by effectively managing building systems based on precise occupancy status without the limitations of traditional sensors.
Implementation Method 1
a passive infrared (PIR) motion sensor for detecting motion in at least part of the space
Data Source
AI summary
A system for controlling one or more components servicing a space of a building based on an occupancy status of the space. The system may comprise a motion sensor, a person sensor for detecting each person passing through an access to the space, and a controller operatively coupled to the motion sensor and the person sensor. The controller may be configured to monitor the motion sensor for detected motion in the space, monitor the person sensor and maintain a people count of people currently in the space. The controller may use the detection of motion and/or the people count to determine if the space is occupied or unoccupied. The controller may then control one or more of the components servicing the space in a first control mode when the space is determined to be occupied and in a second control mode when the space is determined to be unoccupied.