Cooling Device Defrost Scheduling to Reduce Compressor Energy Waste
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Solution Overview
Problem
Cooling devices face inefficiencies due to frost accumulation in the fresh food compartment evaporator, leading to increased energy consumption as the compressor operates unnecessarily to maintain cooling capacity, and existing defrost schedules are either too frequent or too infrequent, causing energy wastage.
Innovation Solution
A control unit dynamically determines the defrost time based on the cooling capacity in the fresh food compartment, using temperature sensors to detect frost accumulation and adjust the compressor operation, ensuring efficient cooling in both compartments while minimizing energy consumption by only initiating the defrost process when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the defrost process interval is set to a fixed time (e.g., 8 hours), then the freezing compartment evaporator remains frost-free, but the fresh food compartment evaporator accumulates frost and loses cooling capacity before the defrost time, causing unnecessary compressor operation and increased energy consumption
Solution Approach 1:
The patent implements dynamic defrost scheduling by continuously monitoring the cooling capacity of the fresh food compartment evaporator and adjusting the defrost timing accordingly. Instead of a fixed defrost interval, the system dynamically determines when defrost is needed based on real-time cooling performance data, allowing the defrost schedule to adapt to varying operational conditions and frost accumulation rates.
Solution Approach 2:
The system employs feedback mechanisms by monitoring the cooling capacity of the fresh food compartment evaporator and using this information to trigger defrost operations. The control unit receives feedback on cooling performance and adjusts the defrost timing based on this feedback, creating a closed-loop control system that optimizes defrost scheduling according to actual evaporator conditions.
2Reliability
If the defrost process interval is reduced to less than 5 hours to prevent frost accumulation in the fresh food compartment, then cooling capacity is maintained, but unnecessary defrost processes occur when the fresh food compartment door is not opened frequently, increasing energy consumption
Solution Approach 1:
The system dynamically adjusts the defrost interval based on actual cooling capacity measurements rather than using a fixed reduced interval. When the evaporator is performing well (cooling capacity above threshold), defrost is delayed or skipped. When cooling capacity drops below the threshold, defrost is triggered immediately, creating a dynamic schedule that adapts to real-time conditions rather than following a predetermined reduced interval.
Solution Approach 2:
The patent changes the parameter of defrost timing from a fixed value to a variable determined by cooling capacity threshold comparisons. The system monitors cooling capacity as a parameter and uses threshold-based decision logic to determine when defrost should occur, allowing the defrost parameter to change based on operational conditions rather than remaining constant.
3Reliability
If the compressor continues to operate to maintain cooling capacity in the fresh food compartment, then cooling performance is maintained, but energy consumption increases due to unnecessary operation when frost accumulation blocks the evaporator
Solution Approach 1:
The system performs preliminary detection of cooling capacity degradation and triggers defrost operations before complete frost blockage occurs. By monitoring cooling capacity and comparing it to threshold values, the system takes preliminary action to remove frost when signs of accumulation are detected, preventing the need for extended compressor operation to compensate for blocked evaporators.
Solution Approach 2:
The control system uses feedback from cooling capacity monitoring to determine when defrost is needed, creating a responsive control mechanism. When feedback indicates cooling capacity has dropped below the threshold, the system triggers defrost to restore capacity, preventing unnecessary compressor operation while maintaining adequate cooling performance.
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 optimizes energy use by preventing unnecessary compressor operation and reducing frost-related inefficiencies, ensuring effective cooling in both compartments while minimizing energy wastage through adaptive defrost scheduling.
Implementation Method 1
at least one first temperature sensor (7) which detects the temperature of the interior of the fresh food compartment (2)
Implementation Method 2
at least one second temperature sensor (8) which detects the temperature of the interior of the freezing compartment (3)
Implementation Method 3
at least one fresh food compartment evaporator (5) which cools down the interior of the fresh food compartment (2) during the cooling cycle
Implementation Method 4
at least one defrost unit (not shown in figures) which carries out the defrost process by removing the defrost accumulated on the fresh food compartment evaporator (5)
Data Source
Figure 1
AI summary
The present invention relates to a cooling device (1) comprising at least one fresh food compartment (2) where foodstuffs and beverages are stored; at least one freezing compartment (3) wherein foodstuffs are stored by freezing; at least one compressor (4) which carries out the cooling cycle; at least one fresh food compartment evaporator (5) which cools down the interior of the fresh food compartment (2) during the cooling cycle; at least one freezing compartment evaporator (6) which cools down the interior of the freezing compartment (3) during the cooling cycle; at least one first temperature sensor (7) which detects the temperature of the interior of the fresh food compartment (2); at least one second temperature sensor (8) which detects the temperature of the interior of the freezing compartment (3); and at least one defrost unit which is connected both to the fresh food compartment evaporator (5) and the freezing compartment evaporator (6) and which carries out the defrost process by removing the defrost accumulated on the fresh food compartment evaporator (5) and the freezing compartment evaporator (6); and at least one control unit which controls the cooling cycle and the defrost cycle. The present invention relates to a cooling device (1) comprising at least one fresh food compartment (2) where foodstuffs and beverages are stored; at least one freezing compartment (3) wherein foodstuffs are stored by freezing; at least one compressor (4) which carries out the cooling cycle; at least one fresh food compartment evaporator (5) which cools down the interior of the fresh food compartment (2) during the cooling cycle; at least one freezing compartment evaporator (6) which cools down the interior of the freezing compartment (3) during the cooling cycle; at least one first temperature sensor (7) which detects the temperature of the interior of the fresh food compartment (2); at least one second temperature sensor (8) which detects the temperature of the interior of the freezing compartment (3); and at least one defrost unit which is connected both to the fresh food compartment evaporator (5) and the freezing compartment evaporator (6) and which carries out the defrost process by removing the defrost accumulated on the fresh food compartment evaporator (5) and the freezing compartment evaporator (6); and at least one control unit which controls the cooling cycle and the defrost cycle.