Geofenced HVAC Control for Occupancy-Based Temperature Setbacks
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Solution Overview
Problem
Building automation systems face challenges in optimizing energy savings while maintaining desired comfort levels, as they lack precise information on when a building is occupied or unoccupied, leading to inefficient temperature control.
Innovation Solution
Implementing geofencing capabilities in building automation systems, where a geofence is defined for the building, and a user's mobile device location is used to control HVAC systems, allowing the building temperature to deviate from a comfort setting based on the user's proximity and duration outside the geofence, thereby optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the building automation system maintains comfort temperature settings continuously, then occupant comfort is ensured, but energy consumption increases
Solution Approach 1:
The system performs preliminary actions by pre-cooling or pre-heating the building before the expected arrival of occupants, and by gradually adjusting temperature settings as occupants approach the building based on their location data. This allows the building to reach comfortable temperatures just in time for occupancy while minimizing energy consumption during unoccupied periods.
Solution Approach 2:
The system dynamically adjusts temperature settings based on real-time occupancy status and predicted arrival times. Instead of static comfort settings, the HVAC system continuously adapts its operation - maintaining comfort when occupied, transitioning to energy-saving modes when unoccupied, and implementing progressive temperature adjustments during transition periods based on occupant proximity.
2Loss of information
If the building automation system uses traditional occupancy sensors, then occupancy detection is achieved, but information accuracy and timeliness deteriorate due to delayed detection
Solution Approach 1:
The system performs preliminary detection by tracking occupant location and movement patterns before they actually enter the building. Using mobile device location data and historical behavior patterns, the system predicts arrival times and prepares accordingly, eliminating the delay inherent in traditional sensors that only detect occupancy after occupants have already entered.
Solution Approach 2:
The system introduces an intermediary approach by using mobile device location data as a mediator between actual occupancy and building system response. Instead of relying solely on physical sensors inside the building, the system uses external location information from smartphones to detect and predict occupancy status, providing earlier and more accurate information.
3Use of energy by stationary object
If the building automation system implements aggressive energy-saving temperature adjustments, then energy consumption is reduced, but comfort levels deteriorate when occupants return
Solution Approach 1:
The system performs preliminary temperature adjustments based on predicted arrival times rather than waiting until occupants return. By using location data to estimate when occupants will arrive, the system begins adjusting temperatures in advance, ensuring comfort is restored before occupants enter while minimizing the duration of energy-saving operation.
Solution Approach 2:
The system implements dynamic, progressive temperature adjustments rather than abrupt changes. As occupants approach the building, the HVAC system gradually transitions from energy-saving settings toward comfort settings, allowing efficient use of time while ensuring comfortable conditions are established before occupancy resumes.
Data Source
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AI summary
An HVAC control system, wherein a building temperature is controlled to a comfort temperature set point when users are inside the geofence and is allowed to deviate from the comfort temperature set point when all users are outside of the geofence. The amount that the building temperature is allowed to deviate from the comfort temperature set point may be in accordance with how long the users have remained outside of the geofence.