Multi-Room Ventilation CO2 Estimation Using Occupancy Detection
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Solution Overview
Problem
Existing ventilation control systems cannot effectively monitor and manage CO2 concentration in multiple rooms using a single ventilation device, leading to potential increases in CO2 levels due to insufficient ventilation.
Innovation Solution
A ventilation control system that includes a ventilation device connected to multiple rooms via air supply and discharge ducts, equipped with CO2 sensors and human detecting sensors, which estimate CO2 concentrations in each room based on presence-absence information and adjust ventilation blower operations accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single CO2 sensor is installed in one room or at the ventilation device inlet, then the device complexity is reduced, but the measurement precision of CO2 concentration in each room deteriorates
Solution Approach 1:
The patent uses human detection sensors to create a proxy measurement system. Instead of installing CO2 sensors in each room, the system detects the presence and number of people in each room, then estimates CO2 concentration based on occupancy data and ventilation performance. This copying approach allows monitoring multiple rooms with minimal sensing infrastructure.
Solution Approach 2:
The patent introduces human detection sensors as an intermediary between the ventilation device and CO2 concentration measurement. These sensors detect occupancy in each room, which serves as intermediate data to infer CO2 levels without directly measuring them. The control device uses this intermediary information to estimate CO2 concentration and adjust ventilation accordingly.
2Measurement precision
If CO2 sensors are installed in each room to monitor CO2 concentration accurately, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent merges the functions of CO2 detection and human detection into a single system. By combining occupancy detection data with ventilation performance data, the system achieves CO2 concentration monitoring capability without requiring separate CO2 sensors in each room. This merging reduces the total number of sensors while maintaining monitoring effectiveness.
Solution Approach 2:
The human detection sensors serve multiple functions: they detect occupancy presence, estimate the number of people, and enable CO2 concentration estimation. This multi-functionality allows a single sensor type to replace what would traditionally require multiple specialized sensors, reducing overall system complexity while maintaining measurement capability.
3Reliability
If ventilation amount is increased to prevent CO2 concentration increase, then the reliability of CO2 concentration control is improved, but the use of energy increases
Solution Approach 1:
The patent implements dynamic ventilation control where the blower operation is continuously adjusted based on real-time occupancy detection and estimated CO2 concentration. The ventilation amount varies dynamically according to actual needs rather than operating at constant high levels, maintaining reliable CO2 control while optimizing energy consumption through adaptive adjustment.
Solution Approach 2:
The system establishes a feedback loop where human detection sensors continuously monitor occupancy, the control device estimates CO2 concentration based on this data, and the blower operation is adjusted accordingly. This feedback mechanism ensures reliable CO2 concentration control by responding to actual conditions while avoiding unnecessary energy consumption when ventilation demand is low.
Data Source
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AI summary
A ventilation control system (50) includes a ventilation device (1) that ventilates multiple rooms (4a, 4b, 4c). The ventilation control system includes a CO2 sensor that measures the CO2 concentration in exhaust air discharged from the multiple rooms (4a, 4b, 4c). The ventilation control system also includes an air conditioner (5), a remote controller (6), and a lighting equipment (7) each of which is installed in a corresponding one of the multiple respective rooms (4a, 4b, 4c) and serves as human detection means for detecting presence of a room occupant. The ventilation device (1) includes a control device that estimates a CO2 concentration of each of the multiple rooms (4a, 4b, 4c) on the basis of the CO2 concentration measured by the CO2 sensor and detection results provided by the multiple human detection means.