Window Fan Control With Indoor-Outdoor Sensing and Rain Protection
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Solution Overview
Problem
Existing window fan systems face issues such as poor air circulation due to lack of exhaust functionality, water infiltration during rain, and limited control over fan operation, which hinders cooling efficiency and increases energy consumption.
Innovation Solution
A window fan control system with an electronic controller, sensors for indoor and outdoor air characteristics, and a damper system to prevent water entry, allowing for automatic operation based on temperature and humidity differences to optimize air exchange and reduce energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a window fan only pulls air into a room without exhaust functionality, then the fan structure is simple, but air circulation is poor and cooling efficiency is hindered
Solution Approach 1:
The fan system is segmented into separate intake and exhaust functions with independent control. The exhaust fan and intake fan operate as separate units that can be independently activated based on environmental conditions, allowing each to optimize its specific function rather than relying on a single fan to perform both tasks
2Device complexity
If a window fan pulls air into a room and exhausts air in the same vertical plane, then the fan structure is simple, but temperature stratification is not eliminated and cooling effectiveness is reduced
Solution Approach 1:
The system transitions from a two-dimensional same-plane air movement to a three-dimensional vertical air exchange system. The exhaust fan is positioned to expel air at a higher elevation while the intake fan draws air in at a lower elevation, creating vertical airflow that effectively eliminates temperature stratification by exchanging air across different height levels
3Device complexity
If a window fan is manually operated, then the control system is simple, but the fan cannot utilize outside air when conditions are favorable, increasing energy consumption
Solution Approach 1:
The control system incorporates sensors that continuously monitor outdoor temperature, humidity, and rainfall conditions, providing feedback to the controller. The controller processes this feedback and automatically activates the exhaust and/or intake fans when conditions are favorable for natural cooling, eliminating the need for manual operation and reducing energy consumption by utilizing free cooling when available
Solution Approach 2:
The system performs self-monitoring and self-control based on environmental conditions. The sensors and controller work together to automatically determine when outside air conditions are favorable and activate the appropriate fan without requiring user intervention, allowing the system to serve itself in optimizing its operation
4Productivity
If a window fan operates during rain events, then cooling function is provided, but water passes through the housing and enters the room
Solution Approach 1:
A rain sensor acts as an intermediary between the environmental conditions and the fan operation. The sensor detects rainfall and provides a signal to the controller, which then prevents fan activation during rain events. This intermediary component allows the system to intelligently distinguish between favorable cooling conditions and unfavorable rainy conditions, enabling cooling function when appropriate while preventing water infiltration
Data Source
AI summary
In the specification and drawings a window fan control system and a method of controlling a fan unit are described and shown. The window fan control system may comprise an electronic controller, an indoor sensor responsive to at least one characteristic of interior air, and an outdoor sensor responsive to at least one characteristic of exterior air. The electronic controller may cause at least one fan of a window fan to be activated when the interior air meets certain criteria relative to a set point and the exterior air meets certain preselected criteria relative to the interior air. The method of controlling a fan unit may comprise the steps of measuring at least one characteristic of exterior air, measuring at least one characteristic of interior air, and activating an intake fan of the fan unit when the interior air meets certain criteria relative to a set point and the exterior air meets certain preselected criteria relative to the interior air.