HVAC controller with a temperature sensor mounted on a flextail conductor
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Solution Overview
Problem
HVAC controllers face challenges in controlling large currents and thermal energy while being sensitive to the thermal environment, requiring a solution to accurately measure ambient temperature without interference from heat-generating components.
Innovation Solution
The use of a thermistor mounted on a flextail, which is a flexible ribbon connector, provides dimensional stability and positions the temperature sensor away from heat-generating components, allowing for accurate ambient temperature readings by isolating it from the printed circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the temperature sensor is mounted on the printed circuit board, then the sensor is dimensionally stable, but the sensor is in close proximity to heat-generating components and cannot provide reliable ambient temperature readings
Solution Approach 1:
The temperature sensor is extracted from the printed circuit board and mounted on a flextail connector instead. This physical separation removes the sensor from the thermal environment of the circuit board, allowing it to measure ambient temperature without interference from heat-generating electronic components while maintaining dimensional stability through the flextail's structural properties
Solution Approach 2:
The flextail connector serves as an intermediary between the printed circuit board and the temperature sensor. It provides the necessary electrical connection while physically isolating the sensor from the thermal environment of the circuit board, enabling accurate temperature measurement without direct thermal coupling
2Measurement precision
If the temperature sensor is placed away from the circuit board to avoid thermal interference, then accurate temperature readings are achieved, but the sensor may move about and lack dimensional stability
Solution Approach 1:
The flextail connector is a flexible ribbon cable that provides both mechanical support and electrical connection. Its flexible yet structurally stable nature allows the temperature sensor to be positioned away from the circuit board for accurate measurement while preventing excessive movement through the connector's inherent dimensional stability
3Power
If the HVAC controller is designed to control large currents and thermal energy, then the controller can manage HVAC components effectively, but the controller itself generates heat that interferes with temperature sensing
Solution Approach 1:
The temperature sensor is extracted from the heat-generating environment of the controller's electronic components and mounted on the flextail connector. This separation allows the controller to handle large currents and thermal energy without the sensor being subjected to the same thermal conditions, ensuring accurate ambient temperature measurement independent of controller-generated heat
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
This configuration enhances the reliability of temperature sensing within the HVAC controller, reducing thermal interference and providing consistent readings, thus improving the controller's performance in managing thermal energy and environmental conditions.
Implementation Method 1
ambient air may be drawn in through the lower side of the housing through a vent or the like by thermal convection caused by the heat generating components of the printed circuit board
Implementation Method 2
The flextail extends from the display to a connector on the printed wiring board forming a wiring connector between the display and the printed wiring board... The temperature sensor is mounted on the flextail and connected to the printed wiring board via electrical conductors of the flex tail
Data Source
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AI summary
A Heating, Ventilation, and Air Conditioning (HVAC) controller may include a housing, a display, a printed wiring board, a flextail, and a temperature sensor. The housing may be configured to house the display, the printed wiring board, the flextail, and the temperature sensor. The flextail may extend from, for example, the display or other component of the HVAC controller, along the interior surface of the housing, and connect to a connector on the printed wiring board. The temperature sensor may be mounted on the flextail, and connected to the printed circuit board via the flex tail or other connection. In some cases, the temperature sensor may be positioned on the flextail such that when the flextail is connected to the printed wiring board, the temperature sensor is electrically connected to the printed wiring board and is facing and/or is adjacent the interior surface of the housing.