Control unit with automatic setback capability
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Solution Overview
Problem
Existing HVAC systems face challenges in accurately detecting periods of non-occupancy, leading to inefficient energy usage as programmable thermostats often fail to reflect users' actual behavior, resulting in unnecessary heating or cooling when the space is unoccupied.
Innovation Solution
A method for automatically adjusting the setpoint temperature based on occupancy detection, using a thermostat that classifies the conditioned space into states like 'Home', 'Away-Normal', 'Away-Vacation', and 'Sleep', and adjusts the temperature accordingly, with adjustable confidence windows and user input overrides to optimize energy savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If programmable thermostats use standard default programs or user-programmed schedules, then energy management capability is improved, but accuracy in reflecting actual occupancy behavior deteriorates
Solution Approach 1:
The system continuously monitors occupancy using motion sensors and automatically adjusts thermostat setpoints based on detected presence or absence. This closed-loop feedback mechanism replaces static schedules with dynamic, behavior-responsive control, accurately reflecting actual occupancy patterns without requiring user programming
Solution Approach 2:
The thermostat system autonomously detects occupancy changes and self-adjusts temperature setpoints without user intervention. The system serves itself by automatically learning and adapting to occupancy patterns through continuous sensor monitoring, eliminating the need for manual schedule programming while optimizing energy management
2Loss of energy
If manual setback operation is required, then energy saving opportunity is improved, but user convenience deteriorates
Solution Approach 1:
The system automatically performs setback operations by monitoring occupancy sensors and autonomously adjusting thermostat setpoints when occupancy changes are detected. This eliminates the need for manual user action while capturing energy savings, making the system both energy-efficient and convenient by removing the operational burden from users
3Loss of energy
If occupancy detection sensitivity is increased, then energy saving during non-occupancy is improved, but false detection of non-occupancy increases
Solution Approach 1:
The system implements a confidence window period that requires occupancy absence to be confirmed for a predetermined duration before triggering setback. This preliminary verification step filters out transient false positives while maintaining sensitivity to genuine occupancy changes, balancing energy savings with detection reliability
Solution Approach 2:
The system dynamically adjusts the confidence window duration based on the specific occupancy sensor and environmental conditions. By making the detection threshold adaptive rather than fixed, the system optimizes the balance between sensitivity for energy savings and specificity to avoid false detections, tailoring the response to actual operational needs
Data Source
AI summary
A device includes a memory configured to store a preexisting schedule and one or more processors configured to perform operations including controlling a temperature within an enclosure according to a first setpoint, wherein the first setpoint is from the preexisting schedule and represents a temperature for when the enclosure is occupied. The operations also include accessing occupancy data indicating occupancy within the enclosure and automatically changing the first setpoint to a second setpoint upon expiration of a predetermined time interval during which no occupancy has been detected. The second setpoint requires less energy to maintain than the first setpoint, and the predetermined time interval is modified based at least in part on received manual settings that indicate occupancy following the changing to the second setpoint.