Thermostat with occupancy detection via proxy measurements of a proxy sensor
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Solution Overview
Problem
Traditional thermostats have limitations in accurately determining occupancy in building spaces, especially in multi-room environments, leading to inefficient HVAC system control and potential energy wastage due to false occupancy indications.
Innovation Solution
The implementation of a controller with a proxy sensor system that measures human-generated gases, such as CO2, and an occupancy sensor to determine presence, allowing for more accurate occupancy detection and adaptive temperature control by comparing concentration levels to baseline values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional occupancy sensors are used to detect presence, then the thermostat can control HVAC systems, but false occupancy indications occur in multi-room environments leading to inaccurate temperature control
Solution Approach 1:
The patent introduces CO2 concentration as an intermediary parameter to indirectly detect occupancy. Instead of directly detecting occupancy, the system measures CO2 levels which correlate with human presence. This intermediary measurement resolves the issue of false occupancy indications by providing a more reliable proxy for actual occupancy status in multi-room environments.
Solution Approach 2:
The patent replaces traditional mechanical/optical occupancy sensors with a gas concentration sensor system. By substituting the detection mechanism from direct occupancy sensing to CO2 concentration measurement, the system achieves more reliable occupancy detection that works effectively across multi-room environments without line-of-sight requirements.
2Loss of energy
If the thermostat continuously monitors occupancy to improve control accuracy, then energy efficiency improves, but system complexity and energy consumption increase
Solution Approach 1:
The patent changes the monitoring parameter from binary occupancy detection to continuous CO2 concentration measurement with baseline comparison. By establishing a baseline CO2 level and detecting deviations from this baseline, the system achieves continuous occupancy monitoring with improved energy efficiency control while managing complexity through a straightforward baseline comparison approach.
Solution Approach 2:
The patent implements feedback by continuously comparing current CO2 concentration levels against established baselines and adjusting HVAC control accordingly. This feedback mechanism enables automatic adaptation to occupancy changes, reducing energy waste while maintaining a relatively simple controller architecture through rule-based decision making.
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 solution enables more precise occupancy detection, even when occupants are not in the same room as the thermostat, leading to improved energy efficiency and optimized HVAC system operation by adjusting temperature settings based on actual occupancy.
Implementation Method 1
a gas sensor configured to measure a concentration level of an occupant generated gas in the building space
Implementation Method 2
the proxy sensor is a vibration sensor configured to measure vibration signals of the building space
Implementation Method 3
the proxy sensor is a light sensor configured to measure a light level of the building space
Implementation Method 4
the proxy sensor is a microphone configured to measure audio signals of the building space
Data Source
AI summary
A controller for controlling an environmental condition of a building space includes a proxy sensor configured to measure a proxy value indicating whether an occupant is within the building space and an occupancy sensor configured to measure an occupancy value. The controller includes a processing circuit configured to determine whether the occupant is within the building space based on the occupancy value of the occupancy sensor, generate a proxy parameter based on a first proxy value measured via the proxy sensor in response to a determination that the occupant is not within the building space based on the occupancy value of the occupancy sensor, determine whether the occupant is within the building based on a second proxy value measured via the proxy sensor and the generated proxy parameter, and control one or more pieces of building equipment to control the environmental condition of the building space.