Air Conditioner Dual-Path Defrost Control to Prevent Compressor Damage
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Solution Overview
Problem
Existing air-conditioning apparatuses face issues with prolonged defrosting operations that lead to reduced heating capacity, liquid refrigerant suction, and compressor damage due to extended defrosting in low temperatures, especially in cryogenic environments.
Innovation Solution
The apparatus includes a refrigeration cycle with a distributor that branches refrigerant flow into upper and lower paths in the outdoor heat exchanger, equipped with dual temperature detecting units to control defrosting based on the refrigerant temperatures in both paths, ensuring the operation is terminated when both units reach their respective target temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the defrosting operation is extended to ensure complete ice melting, then the ice melting capability is improved, but the heating capacity is reduced and the risk of liquid refrigerant suction increases
Solution Approach 1:
The patent employs multiple temperature detection units positioned at different locations (outdoor heat exchanger inlet, outlet, and compressor suction) to continuously monitor refrigerant temperatures. The control unit receives this feedback and dynamically adjusts the defrosting operation duration and intensity, terminating defrosting when temperature criteria are met rather than using fixed extended timing. This feedback mechanism ensures complete ice melting while preventing unnecessary prolonged defrosting that would reduce heating capacity.
Solution Approach 2:
The defrosting control system transitions from static fixed-duration defrosting to dynamic adaptive defrosting. The control unit adjusts defrosting parameters in real-time based on detected refrigerant temperatures and environmental conditions, optimizing the balance between ice melting effectiveness and heating capacity maintenance.
2Device complexity
If the defrosting operation is performed based on single temperature detection, then the device complexity is reduced, but the measurement precision is insufficient to detect ice melting completion accurately
Solution Approach 1:
The outdoor heat exchanger is divided into multiple monitoring zones with temperature detection units positioned at different locations (inlet, outlet, and specific heat transfer fin areas). This segmentation allows independent temperature monitoring of different regions, enabling accurate detection of ice melting completion in each zone and providing comprehensive coverage of the heat exchanger surface.
Solution Approach 2:
Multiple temperature detection results from different locations are merged and evaluated collectively by the control unit. The control logic integrates signals from all temperature detection units to make a comprehensive determination of ice melting completion, achieving high measurement precision through combined data from multiple sensors rather than relying on a single detection point.
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 allows for efficient defrosting that minimizes unnecessary operations, effectively melting ice when present while preventing damage to components by ensuring the defrosting duration is optimized.
Implementation Method 1
a distributor (32) configured to branch, at an intermediate portion of the heat transfer fin, a refrigerant flow path into an upper path and a lower path of the heat transfer tube
Implementation Method 2
a heat transfer tube connected with and penetrating through the plurality of heat transfer fins
Implementation Method 3
heat transfer amounts between the refrigerant and air
Implementation Method 4
a plurality of heat transfer fins arranged in parallel at intervals
Implementation Method 5
an expansion valve, and an indoor heat exchanger in this order by refrigerant pipes
Implementation Method 6
a compressor, a four-way valve, an outdoor heat exchanger
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The air-conditioning apparatus has a refrigeration cycle for circulating refrigerant by connecting a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger in this order with refrigerant pipes. The outdoor heat exchanger includes a plurality of heat transfer fins, a heat transfer tube having a plurality of paths, a distributor configured to branch, at an intermediate portion of the heat transfer fin, a refrigerant flow path into an upper path and a lower path of the heat transfer tube, a first temperature detecting unit configured to detect a refrigerant temperature merged through the distributor, a second temperature detecting unit configured to detect a refrigerant temperature of a refrigerant passing through the lower path, and a controller for performing control for terminating the defrosting operation when the refrigerant temperature detected by the first temperature detecting unit reaches the first target temperature and the refrigerant temperature detected by the second temperature detecting unit reaches the second target temperature during the defrosting operation.