Dehumidifier Heating Control via Temperature Gradient Analysis
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Solution Overview
Problem
Existing methods for drying air dehumidifiers in oil-insulated transformers and tap changers require costly and accurate air flow sensors to determine if air is entering or leaving the oil expansion tank, which is inefficient and expensive.
Innovation Solution
A method that uses temperature gradient analysis over time slots to determine air flow direction, allowing heating of the absorption agent only when air is not entering the tank, utilizing a single temperature sensor to calculate and store temperature gradients, and initiating heating based on consistent patterns of temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If air flow sensors are used to detect air flow direction, then accurate detection of air flow is achieved, but device cost and complexity increase significantly
Solution Approach 1:
The patent introduces temperature as an intermediary parameter to indirectly detect air flow direction. Instead of directly measuring air flow with complex sensors, the system measures temperature changes in the absorption agent over time. The temperature gradient serves as a mediator that reflects air flow conditions, allowing the system to determine whether air is entering or leaving the expansion tank without direct air flow measurement.
Solution Approach 2:
The patent replaces mechanical air flow sensors with a thermal-based detection system. By using temperature sensors to measure temperature changes in the absorption agent and calculating temperature gradients, the system substitutes direct mechanical air flow measurement with indirect thermal field analysis, thereby eliminating the need for complex air flow sensing mechanisms.
2Measurement precision
If highly accurate air flow sensors are used for low air throughput detection, then detection precision is improved, but sensor cost increases
Solution Approach 1:
The patent uses temperature change as an intermediary that amplifies the detection signal for low air flow conditions. The temperature gradient in the absorption agent provides a measurable parameter that reflects even minimal air flow, allowing standard temperature sensors to detect conditions that would require highly accurate and expensive air flow sensors for direct measurement.
Solution Approach 2:
The patent changes the measurement parameter from direct air flow rate to temperature gradient over time. By monitoring how temperature changes in the absorption agent rather than measuring air flow directly, the system transforms a difficult-to-measure parameter (low air flow) into an easier-to-measure parameter (temperature change), reducing sensor cost while maintaining detection precision.
3Productivity
If heating is performed when air is entering the expansion tank, then drying efficiency is improved, but harmful effects occur due to improper heating conditions
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors temperature changes in the absorption agent and uses this information to control heating operation. By calculating the temperature gradient over time and determining air flow direction based on temperature trends, the system provides feedback to the heating control, ensuring heating is only activated when air flow conditions are appropriate (i.e., when air is not entering the expansion tank).
Solution Approach 2:
The patent performs preliminary detection of air flow direction through temperature gradient analysis before initiating heating. By monitoring temperature changes and determining the thermal state of the absorption agent in advance, the system ensures that heating is only started when conditions are favorable, preventing harmful heating effects before they can occur.
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
Eliminates the need for expensive air flow sensors by accurately determining air flow direction through temperature gradient analysis, ensuring efficient and cost-effective drying of the absorption agent.
Implementation Method 1
determining at the beginning of a first time and at a second time of each time slot in each case the temperature (θ2−θ1) at the intake and calculating a temperature gradient (dθ/dt) therefrom
Implementation Method 2
an electric heater is provided to heat up and thereby dry the regenerable absorption agent
Data Source
AI summary
The invention relates to a method for controlling a heatable dehumidifier. The heating of the dehumidifier is to be actuated only when several congruent time windows within which a temperature gradient is greater than or equal to 0 could be determined during a certain period of time, i.e. the heating is to be actuated only when no air flows into the interior of the expansion vessel of the transformer.