Evaporator Defrost Control Based on Real-Time Icing State
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Solution Overview
Problem
Conventional cooling devices for refrigeration and freezer units in food markets rely on time-dependent defrosting processes, which can lead to unnecessary energy consumption and increased CO2 emissions due to inefficient de-icing of the evaporator.
Innovation Solution
A method and system for controlling the defrosting process in cooling devices based on the actual degree of icing of the evaporator, using existing sensors to monitor temperature, pressure, and compressor parameters, and activating the defrosting system only when the icing exceeds a predetermined threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time-dependent defrosting process is used, then the evaporator is de-iced regularly, but energy consumption increases due to unnecessary defrosting operations
Solution Approach 1:
The system uses feedback from multiple sensors (cold air temperature sensor, refrigerant temperature sensor, refrigerant pressure sensor, compressor power sensor) to continuously monitor the actual icing state of the evaporator and adjusts the defrosting operation accordingly, eliminating unnecessary defrosting cycles and reducing energy consumption
Solution Approach 2:
The defrosting control system transitions from a static time-dependent approach to a dynamic state-dependent approach, where defrosting is activated or deactivated based on real-time assessment of icing conditions through sensor data evaluation
2Reliability
If defrosting system is activated frequently, then evaporator is kept free of ice, but energy costs and CO2 emissions increase
Solution Approach 1:
The system applies partial action by activating the defrosting system only to the extent necessary - only when the evaluated icing degree exceeds the threshold - rather than applying continuous or excessive defrosting, thereby minimizing energy waste while maintaining adequate evaporator performance
3Device complexity
If no additional sensors are installed in the evaporator, then device complexity is reduced, but measurement precision of icing degree is improved through alternative sensor combination
Solution Approach 1:
The system makes existing sensors serve multiple functions - the cold air temperature sensor, refrigerant temperature sensor, refrigerant pressure sensor, and compressor power sensor are used not only for their primary cooling control functions but also collectively for determining the icing degree of the evaporator, eliminating the need for additional dedicated sensors
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 reduces energy consumption, energy costs, and CO2 emissions by ensuring that the defrosting process is initiated only when necessary, thereby maintaining the effectiveness of the cooling device while minimizing wasteful energy use.
Implementation Method 1
a cold air flow for the object exchanging heat with the refrigerant in the evaporator
Implementation Method 2
This causes the water contained in the air to condense in the evaporator, as a result of which the evaporator can ice up
Implementation Method 3
a defrosting system for de-icing the evaporator
Data Source
AI summary
A cooling device for, for example, a cooling object has a refrigerant circuit with an evaporator, in which a cold air flow for the cooling object exchanges heat with the refrigerant, and a defrosting system for de-icing the evaporator. The defrosting system is controlled according to the degree of icing of the evaporator. The degree of icing of the evaporator is determined by the control unit of the defrosting system on the basis of the temperature of the cold air flow from the cooling object to the evaporator, the temperature and/or the operating pressure of the refrigerant upstream of the evaporator and at least one operating parameter of the compressor.