Presence detection
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Solution Overview
Problem
Existing presence detection systems for indoor occupancy estimation are inefficient and lack the ability to provide detailed occupancy data, such as the number of people in a room, which is crucial for optimizing space usage and controlling services like ventilation.
Innovation Solution
Estimating occupancy by combining measurements of air quality aspects like CO2 concentration, VOCs, and humidity with knowledge of room ventilation rate, using model functions like exponential curves to predict steady-state values, and utilizing stored ventilation rate parameters from memory or histograms for improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional presence detection systems (infrared sensors, radar sensors, motion sensors, acoustic sensors, ultrasound sensors, vibration sensors, cameras) are used to detect occupancy, then presence detection capability is provided, but the systems are inefficient and lack the ability to provide detailed occupancy data such as the number of people in a room
Solution Approach 1:
The patent replaces traditional mechanical/optical presence detection systems (infrared sensors, radar sensors, motion sensors, cameras) with a chemical sensing approach using CO2 sensors to detect occupancy. This substitution enables precise measurement of the number of people in a room by measuring CO2 concentration, which directly correlates with occupancy levels, thereby providing both high measurement precision and system efficiency.
2Ease of operation
If simple binary detection (present or not present) is used, then detection simplicity is maintained, but detailed occupancy information (number of people) cannot be obtained
Solution Approach 1:
The patent changes the detection parameter from simple binary presence/absence to continuous CO2 concentration measurement. By measuring the concentration of CO2 in the air, the system can determine the exact number of people in a room, transforming the detection output from a simple binary state to a detailed quantitative measurement that preserves all occupancy information.
3Measurement precision
If air quality measurements (CO2 concentration, VOC concentration, humidity level) are combined with ventilation rate data, then accurate occupancy estimation is achieved, but system complexity increases
Solution Approach 1:
The patent makes the air quality monitoring system multi-functional by using the same CO2, VOC, and humidity sensors for both air quality assessment and occupancy detection. The ventilation rate data, already collected for air quality control purposes, is repurposed for occupancy estimation. This universal use of existing sensors and data eliminates the need for additional dedicated occupancy sensors, thereby achieving accurate occupancy estimation without increasing system complexity.
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
Enables precise estimation of room occupancy, allowing for detailed analysis of space usage and effective control of services, enhancing efficiency and comfort by accurately determining the number of people present.
Implementation Method 1
CO2 is emitted by people when they breathe
Implementation Method 2
Worn clothing and perfumes emit VOCs (Volatile Organic Compounds)
Implementation Method 3
Humidity is influenced by breathing as well as by other factors such as sweating or wet clothing
Data Source
AI summary
A method of estimating occupancy of a room, comprising: acquiring a plurality of measurements of an aspect of air quality in the room; and estimating the occupancy of the room based on the plurality of measurements and a room ventilation rate parameter. By estimating the occupancy of the room based on aspects of air quality, it is possible to detect occupancy based on data from sensors which may already be present for other purposes (e.g. for measuring air quality). Combining measurements of air quality with knowledge related to ventilation rate results in information indicative of the occupancy. Estimating the number of people in the room allows detailed analysis and control to be undertaken. Such occupancy data can also be used to control other services, e.g. to control the ventilation or to provide information about the number of people present.