Method of maintaining a position of an airflow-direction control element of a HVAC system
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Solution Overview
Problem
HVAC systems require a constant holding current to maintain vent flap positions, reducing efficiency due to mechanical play and vibrations, and mechanically irreversible actuators consume excessive power.
Innovation Solution
A method and HVAC system utilizing an airflow-direction-controller actuator with a position sensor and controller to determine and adjust the position of movable members, eliminating the need for a constant holding current by providing current only when necessary to correct deviations from target positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant holding current is passed through the electric motor to maintain vent flap position, then the vent flap position is maintained against mechanical play and vibrations, but the energy consumption increases
Solution Approach 1:
The control system uses periodic sensing and corrective actuation instead of continuous holding. The position sensor periodically checks the vent flap position, and the motor is activated only when deviations are detected, converting continuous energy consumption into periodic action.
Solution Approach 2:
A position sensor provides feedback about the actual vent flap position to the controller. The controller compares the actual position with the target position and activates the motor only when correction is needed, creating a closed-loop feedback system that eliminates the need for constant holding current.
2Loss of energy
If a mechanically irreversible actuator such as a worm gear is used to prevent position drift without holding current, then the holding current is eliminated, but the actuator efficiency decreases and power consumption increases
Solution Approach 1:
The patent replaces the mechanically irreversible actuator (worm gear) with a reversible electric motor combined with electronic feedback control. This substitution eliminates the inherent mechanical inefficiency of irreversible mechanisms while achieving the same position-maintenance function through electronic control.
Solution Approach 2:
The system changes the operational parameters of the motor by controlling it to operate only when necessary (when position deviation exceeds threshold), rather than maintaining constant mechanical engagement. This dynamic parameter adjustment optimizes energy consumption while maintaining position stability.
3Loss of energy
If a high efficiency gear train is used in the actuator, then the likelihood of position change due to vibrations increases, but the energy efficiency improves
Solution Approach 1:
The position sensor continuously monitors the vent flap position and provides feedback to the controller. When vibrations or mechanical play cause position deviations, the feedback mechanism detects these changes and activates the motor to correct the position, maintaining stability despite using high-efficiency (more vulnerable to vibrations) gear trains.
Data Source
AI summary
A method of maintaining a position of an airflow-direction control element 16 of a HVAC system, comprising the steps of, a] determining a position of at least one movable member of an airflow-direction control mechanism of the HVAC system; and b] calculating whether the movable member is at a target position associated with a required position of the airflow-direction control element, and if not, activating an airflow-direction-controller actuator of the HVAC system to effect a change in the position of the movable member thereby bringing the airflow-direction control element to or towards the said required position. A HVAC system suitable for implementing such a method is also provided and capable of improving the overall efficiency of operation.