Human-Sensing Ventilator Flow Control for Bathroom Draft Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional ventilators often waste energy due to wide flow rate adjustment intervals and struggle to maintain effective ventilation in bathrooms, where low flow rates are necessary to avoid cold drafts, and high flow rates are needed for quick moisture removal, while also being inefficient with alternating-current motors and prone to power interruptions.

Innovation Solution

A ventilator with a direct-current motor, a human sensor, and a control unit that adjusts flow rates steplessly or in small intervals, allowing for fixed high flow rates when occupied and reduced flow rates when unoccupied, with a rotatable suction louver and detection defining unit to optimize ventilation based on user presence and activity, ensuring efficient moisture removal and power savings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the ventilator operates at high flow rate to quickly remove moisture, then moisture removal efficiency is improved, but cold drafts are generated causing user discomfort

Engineering Contradiction:

Improvemoisture removal efficiencyVSAvoidcold draft

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The ventilator dynamically adjusts the fan motor's rotation speed based on real-time detection of user presence and activity state. When a user is present and bathing, the system maintains low flow rate to prevent cold drafts. When the user leaves or is in high-moisture activities, the system increases flow rate to accelerate moisture removal, thus resolving the contradiction between moisture removal efficiency and user comfort through dynamic adaptation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses a human sensor to detect user presence and a control unit to continuously monitor and adjust the ventilation flow rate based on detected conditions. This feedback mechanism allows the ventilator to respond to changing environmental conditions and user needs, switching between low flow rate (when user is present) and high flow rate (when user is absent or moisture is high), thereby balancing moisture removal efficiency with user comfort.

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If the ventilator operates at low flow rate to avoid cold drafts, then user comfort is improved, but moisture removal efficiency deteriorates

Engineering Contradiction:

Improvecold draftVSAvoidmoisture removal efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system implements periodic switching between low flow rate operation (when user is present) and high flow rate operation (when user is absent or moisture accumulation is detected). This periodic action allows the ventilator to alternate between comfort-oriented and efficiency-oriented modes, ensuring both user comfort during occupancy and effective moisture removal during unoccupied periods.

Inventive Principle:

Principle #19Periodic action

3Device complexity

If two-step flow rate adjustment is used, then device complexity is reduced, but manufacturing precision deteriorates due to wide adjusting intervals

Engineering Contradiction:

Improveflow rate adjustment mechanismVSAvoidflow rate adjustment precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts the fan motor's rotation speed based on real-time detection of user presence and activity state. When a user is present and bathing, the system maintains low flow rate to prevent cold drafts. When the user leaves or is in high-moisture activities, the system increases flow rate to accelerate moisture removal, thus resolving the contradiction between moisture removal efficiency and user comfort through dynamic adaptation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the control parameter from discrete two-step flow rate adjustment to continuous rotation speed control of the fan motor. By using a control unit that can adjust the motor speed continuously based on sensor input, the system achieves precise flow rate control without the limitations of fixed adjustment steps, thereby improving manufacturing precision while maintaining acceptable device complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS7455583B2Ventilator including a control unit and human sensor

Publication Date: 2008.11.25 PANASONIC HOLDINGS CORP

AI summary

The invention presents a ventilator capable of obtaining an optimum flow rate required in ordinary ventilation. The ventilator comprises an exhaust fan motor for exhausting room air by force, and a human sensor for detecting the presence of human body. It further comprises a control unit for controlling the fan motor by receiving a signal from the human sensor, and a flow rate adjusting unit for adjusting the ventilation flow rate by the exhaust fan motor. The control unit, when detecting a signal from the human sensor, operates the exhaust fan motor for a specified time at fixed flow rate, and while not detecting, it operates the exhaust fan motor all the time at ventilated flow rate adjusted by the flow rate adjusting unit. During this ordinary operation, the flow rate may be adjusted by the flow rate adjusting unit either steplessly or in multiple steps at small intervals, and thereby a ventilator capable of obtaining an optimum flow rate required in ordinary ventilation can be presented.