Smart Thermostat Away-State Control Using Occupancy Qualification
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Solution Overview
Problem
Existing energy-saving technologies for HVAC systems face challenges in user adoption due to complexity and difficulty in programming, leading to inefficient energy usage, as users often fail to manually adjust settings according to their occupancy patterns, resulting in missed opportunities for energy and cost savings.
Innovation Solution
A thermostat with an integrated processing system and occupancy sensors that automatically determines an away-state mode by analyzing sensor readings during a trial period, enabling an automated setpoint temperature setback only if sufficient occupancy indications are detected, thus simplifying user interaction and enhancing energy-saving capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a programmable thermostat with default schedules is used, then energy-saving capability is improved, but device complexity increases making it difficult for users to program
Solution Approach 1:
The thermostat automatically performs occupancy detection and schedule adjustment without requiring user programming. The system qualifies occupancy sensors during a trial period and then autonomously implements away-state setback schedules based on detected occupancy patterns, eliminating the need for manual user configuration while maintaining energy-saving functionality
Solution Approach 2:
The system implements a trial period during which occupancy sensors are qualified before being used for automatic control. This preliminary action ensures sensor reliability is established before the system begins autonomous energy-saving operations, resolving the contradiction by preparing the system in advance rather than requiring complex user programming
2Loss of energy
If manual setback operation is required, then energy-saving opportunity is improved, but ease of operation deteriorates as users seldom perform the task
Solution Approach 1:
The thermostat system performs automatic occupancy-based setback operations without requiring manual user intervention. The occupancy sensors continuously monitor the space and the processing system automatically adjusts HVAC setpoints based on detected occupancy states, capturing energy-saving opportunities that would otherwise be missed due to user inaction
Solution Approach 2:
The system continuously monitors occupancy sensor signals and uses this feedback to dynamically adjust thermostat setpoints. When sensors indicate an away state, the system automatically implements energy-saving setback schedules, and when occupancy is detected, it resumes normal scheduling, creating a closed-loop automatic control system that captures energy savings without user effort
3Extent of automation
If occupancy sensors are immediately activated, then automation capability is improved, but reliability deteriorates due to insufficient sensor qualification
Solution Approach 1:
The system implements a trial period before activating automatic occupancy-based control. During this period, occupancy sensors are monitored and qualified to ensure they provide reliable signals. Only after successful qualification during the trial period does the system enable automatic away-state functionality, ensuring both automation capability and sensor reliability
4Reliability
If a trial period for sensor qualification is implemented, then sensor reliability is improved, but time to activate energy-saving features increases
Solution Approach 1:
The system implements a trial period of sufficient duration to qualify sensors with adequate reliability, accepting the time delay as necessary to ensure proper operation. The trial period is calibrated to be the minimum time required for reliable sensor qualification while enabling energy-saving functionality as soon as possible once qualification is complete
Data Source
AI summary
A control unit for controlling the operation of at least one smart-home system may include at least one occupancy sensor and a processing system. The processing system may be configured to receive readings from the at least one occupancy sensor during a trial period; compare information derived from the readings to at least one threshold criterion to establish whether the one or more occupancy sensors reliably determined occupancy of an enclosure in which the control unit is installed during the trial period; and enable an away-state feature of the control unit if it is determined that the one or more occupancy sensors reliably determined occupancy of an enclosure during the trial period.