Geofence plus schedule for a building controller
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Solution Overview
Problem
Existing building control systems lack additional control options when determining occupancy, particularly when transitioning between occupied and unoccupied states, leading to inefficiencies in energy usage.
Innovation Solution
A method combining geofencing and time-based scheduling to control building systems, where a mobile device's location is used to determine occupancy, switching between AWAY and HOME settings based on geofence presence and time-based schedules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If geofencing is used to determine occupancy, then energy efficiency is improved by avoiding conditioning of unoccupied spaces, but control flexibility is reduced when the building is determined to be occupied
Solution Approach 1:
The control system segments the occupied state into multiple time periods with different settings. When the building is determined to be occupied via geofencing, the system divides the day into distinct time periods (e.g., morning, afternoon, evening) and applies different HVAC settings to each period, thereby restoring control flexibility while maintaining energy efficiency benefits
Solution Approach 2:
The system dynamically switches between geofence-based control and time-based schedule control. When occupants are detected inside the geofence, the system dynamically adapts by applying time-based schedules with multiple settings throughout the day, rather than using a single static setting, thus providing both energy efficiency and control flexibility
2Device complexity
If a single occupied setpoint is used when the building is occupied, then system simplicity is maintained, but energy efficiency is reduced due to lack of optimization across different times of day
Solution Approach 1:
The system implements periodic action by dividing the occupied period into multiple time periods with different settings. Instead of applying a single continuous occupied setpoint, the system periodically changes settings according to predetermined time periods (e.g., higher cooling during daytime, lower cooling during evening), optimizing energy efficiency while maintaining system simplicity through automated schedule-based control
Data Source
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AI summary
A building control system that uses geofencing in conjunction with a timebased schedule when control one or more building systems. In one example, geofencing may be used to determine if the building is occupied or unoccupied. If the building is determined to be unoccupied via geofencing, the building controller may control to an unoccupied setpoint. If the building is determined to be occupied via geofencing, the HVAC controller may control in accordance with a time-based schedule.