Refrigerator Mullion Moisture Sensing for Peak-Demand Heater Control
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Solution Overview
Problem
Refrigerators face challenges in managing anti-sweat heaters during peak energy demand periods, as disabling them risks moisture accumulation and potential drips, while reactivating them during peak pricing may not be efficient due to the small power consumption of existing heaters.
Innovation Solution
A controller-activated anti-sweat heater system that includes a moisture detecting sensor, specifically an impedance sensing device, to cyclically or temporarily reactivate the heater when moisture is detected, ensuring effective moisture management without continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anti-sweat heater is continuously operated to prevent moisture accumulation, then moisture protection is improved, but energy consumption increases during peak demand periods
Solution Approach 1:
The anti-sweat heater operates periodically rather than continuously. The controller monitors moisture conditions and activates the heater only when moisture detection thresholds are exceeded, allowing energy savings during dry periods while maintaining reliable moisture protection when needed.
Solution Approach 2:
The system incorporates moisture sensors that provide feedback to the controller about humidity levels in the refrigerator compartment. This feedback loop enables the controller to make informed decisions about heater operation, activating only when moisture conditions warrant intervention, thus balancing reliability and energy consumption.
2Use of energy by moving object
If the anti-sweat heater is disabled during peak demand periods to save energy, then energy consumption is reduced, but moisture accumulation and water drippage risk increase
Solution Approach 1:
The heater is activated periodically based on moisture detection rather than operating continuously. During peak demand periods, the system monitors moisture levels and only activates the heater when necessary, reducing energy consumption while preventing harmful moisture accumulation through targeted intervention.
Solution Approach 2:
The moisture sensors and controller enable the system to self-monitor and self-regulate heater operation. The system automatically detects moisture conditions and activates the heater only when needed, eliminating the need for continuous operation while maintaining protection against moisture accumulation.
3Use of energy by moving object
If a moisture detection sensor is added to enable conditional heater operation, then energy savings are improved, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical moisture management mechanisms with electronic sensors and a simple controller. The moisture detection sensors and electronic control system provide precise, automated decision-making about heater operation, achieving energy savings without requiring complex mechanical structures or manual intervention.
Solution Approach 2:
The moisture sensors provide feedback to the controller, which automatically adjusts heater operation. This feedback mechanism enables sophisticated energy management with relatively simple components, as the sensor-controller-heater loop handles complexity through intelligent control rather than mechanical complexity.
4Reliability
If the anti-sweat heater is reactivated during peak pricing periods, then moisture protection is maintained, but energy cost savings are reduced
Solution Approach 1:
The heater operates periodically based on actual moisture conditions rather than continuously or solely based on pricing signals. The controller monitors moisture levels and activates the heater only when thresholds are exceeded, maintaining reliable moisture protection while minimizing energy consumption and maximizing cost savings during peak pricing periods.
Solution Approach 2:
Moisture sensors provide real-time feedback to the controller, enabling data-driven decisions about heater operation. This feedback system ensures the heater is activated only when moisture protection is actually needed, balancing reliability with energy cost efficiency by avoiding unnecessary operation during peak pricing periods.
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 solution allows for low-cost energy savings during peak demand periods without moisture issues, automatically overriding energy-saving mode to prevent sweat and fog from reaching the floor, with no moving parts and reduced thermal insulation to enhance detection accuracy.
Implementation Method 1
A controller-activated anti-sweat heater system that includes a moisture detecting sensor, specifically an impedance sensing device
Implementation Method 2
a heater such as a low wattage electric resistance heater is typically employed
Implementation Method 3
the metal housing surface is exposed to 0° air from the freezer compartment... and exposed to ambient air associated with the room along another edge of the gasket. Since the metal housing is thermally conductive, a portion of this metal... conducts the heat in and conducts the cold out. As a result, a gap region of the housing between the gaskets or adjacent the gaskets is exposed to ambient air and can be at a temperature below the dew point temperature
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An appliance such as a refrigerator (100) receives a demand response signal indicating a peak demand period and operates the refrigerator in an energy savings mode by disabling an anti-sweat heater. A sensor (180) on an external surface of the refrigerator enables the anti-sweat heater during the peak demand period if moisture is detected by the sensor. A preselected location (170) can be defined where incipient moisture would form such as reducing the amount of insulation in this location. By forming a depression in the location and using an impedance-type sensor, moisture can be easily detected. The sensor signal is sent to the controller which then activates the anti-sweat heater to remove the moisture.