Heat Exchanger Valve Control Using Dual Temperature Sensing
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Solution Overview
Problem
Existing valve control systems for heating or cooling fluid in heat exchangers face inefficiencies due to energy wastage and imprecise detection of valve position, particularly when using electric actuators, as they require significant energy to determine the closing point and often result in oscillating movements.
Innovation Solution
A valve arrangement utilizing two temperature sensors with different thermal resistances to detect the closing condition of the valve by comparing ambient and valve temperatures, allowing for precise control and reducing energy consumption by only actuating the valve when the heat source is active, and using a stepping motor to open the valve step-wise with pauses to determine the opening point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force-based detection method is used to determine valve closing position, then valve position information can be obtained, but electrical energy consumption increases significantly
Solution Approach 1:
The patent replaces the mechanical/force-based detection method with a thermal detection method. Instead of measuring force to detect valve closing position, the system uses temperature sensors to detect thermal changes in the valve body that occur when the valve transitions between open and closed states. This substitution of measurement principle dramatically reduces energy consumption while maintaining detection accuracy.
Solution Approach 2:
The patent changes the detection parameter from mechanical force to thermal properties. By monitoring temperature changes in the valve body rather than measuring mechanical force, the system achieves valve position detection with minimal energy consumption. The thermal parameter provides a passive, low-energy alternative to active force measurement.
2Measurement precision
If electric actuator continuously adjusts valve position to maintain room temperature, then temperature control precision improves, but energy waste increases due to oscillating movements
Solution Approach 1:
The patent enables the valve system to self-determine its position state through thermal detection without requiring continuous active control adjustments. By detecting temperature changes that naturally occur during valve operation, the system can identify opening and closing points without needing to continuously oscillate or actively adjust, thereby reducing energy waste while maintaining control precision.
Solution Approach 2:
The system uses thermal feedback from the valve body temperature to determine valve position and trigger control actions only when necessary. This feedback mechanism allows the controller to understand valve state without continuous adjustment, reducing oscillating movements and associated energy waste while maintaining accurate temperature control.
3Device complexity
If single temperature sensor is used to detect ambient temperature, then device complexity is reduced, but temperature measurement accuracy deteriorates due to lack of compensation for valve proximity effects
Solution Approach 1:
The patent uses the valve body itself as a thermal intermediary or mediator. The valve body's temperature, detected by the temperature sensor, serves as an intermediate indicator that provides information about both the valve position and the thermal environment. This intermediary approach allows accurate temperature measurement and valve state detection without requiring multiple sensors placed at different locations.
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 approach enables accurate detection of the valve's opening and closing positions with reduced energy consumption, optimizing the control of heating or cooling fluid flow and signaling the heat source to conserve energy when all valves are closed.
Implementation Method 1
a thermal resistance between the first temperature sensor and the valve being greater than a thermal resistance between the second temperature sensor and the valve
Data Source
AI summary
A valve arrangement is provided, (1) comprising: a valve (2) for controlling a flow of heating or cooling fluid through a heat exchanger, an actuator (12) for actuating said valve (2), control means (15) for controlling said actuator (12), a first temperature sensor (18) connected to said control means (15), a thermal resistance between the first temperature sensor (18) and the valve (2) being greater than a thermal resistance between the second temperature sensor (19) and the valve (2). It is intended to improve control of the valve. To this end the first temperature sensor (18) and the second temperature sensor (19) are part of detector means detecting a closing condition of the valve (2).