Return Air Intake De-Icing Using Periodic Heater Activation
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Solution Overview
Problem
Ice buildup in the return air intake of transport refrigeration systems can lead to blockages, inhibiting the performance of the refrigeration unit and transport refrigeration system, particularly due to increased humidity from perishable cargo expelling water vapor.
Innovation Solution
A method and apparatus that utilize a controller to deactivate certain components of the refrigeration system, activate an electric resistance heater to a selected temperature, and allow the heat to rise to the return air intake for a specified time period to de-ice the area, thereby preventing ice buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigeration system operates continuously to cool perishable goods, then the cooling performance is maintained, but ice builds up on the return air intake due to water vapor from the cargo
Solution Approach 1:
The system performs de-icing action before the ice buildup completely blocks the return air intake. The controller monitors system operation and initiates heater activation at predetermined intervals or when ice accumulation is detected, preventing complete blockage while maintaining continuous cooling operation.
Solution Approach 2:
The de-icing process operates periodically rather than continuously. The controller activates the heater for predetermined time intervals to melt ice buildup, then deactivates it to allow normal cooling operation, creating a cyclical pattern that balances ice removal with energy consumption and cooling performance.
2Object-affected harmful factors
If a heater is activated to de-ice the return air intake, then ice buildup is removed, but energy consumption increases
Solution Approach 1:
The heater operates periodically rather than continuously, activating only when ice buildup is detected or at predetermined intervals. This reduces overall energy consumption compared to continuous operation while still effectively removing ice when needed.
Solution Approach 2:
The controller monitors system conditions and activates the heater based on detected ice buildup or predetermined criteria. This feedback-based control ensures the heater operates only when necessary, optimizing energy usage while maintaining effective de-icing.
3Speed
If the heater temperature is increased to accelerate ice melting, then de-icing speed improves, but risk of damaging surrounding components increases
Solution Approach 1:
The controller adjusts the heater temperature to optimal levels for safe and effective de-icing. By controlling the temperature parameter within a specific range, the system achieves adequate ice melting speed while preventing excessive heat that could damage surrounding refrigeration components.
Solution Approach 2:
The heater is positioned to apply heat locally to the return air intake area where ice buildup occurs, rather than heating the entire refrigeration space. This concentrated local heating achieves faster de-icing speed at the target location while minimizing thermal exposure to other components.
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
Effectively de-ices the return air intake by controlling the refrigeration system components and using a heater to prevent ice formation, ensuring the continued operation and efficiency of the transport refrigeration system.
Implementation Method 1
activating, using the controller, the heater when the de-icing mode is required; adjusting, using the controller, the temperature of the heater to a selected temperature
Implementation Method 2
allowing the heat to rise to the return air intake for a specified time period to de-ice the area
Implementation Method 3
allowing the heat to rise to the return air intake
Implementation Method 4
passed through the airside of the evaporator in heat exchange relationship with refrigerant whereby the refrigerant absorbs heat from the air, thereby cooling the air
Implementation Method 5
The water vapor may freeze into ice on a return air intake as it flows into the refrigeration unit
Data Source
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AI summary
A method (300) of de-icing a return air intake of a transport refrigeration system is provided. The method comprises using a controller for controlling the refrigeration system; determining (306) when de-icing mode is required; deactivating (308) an evaporator and an evaporator fan of the refrigeration system when de-icing mode is required; activating (310) a heater when de-icing mode is required; adjusting (312) the temperature of the heater to a selected temperature; deactivating (314) the heater when the heater has reached the selected temperature; and permitting (316) the refrigeration system to remain deactivated for a selected time period.