Method and device for controlling freezing prevention during refrigeration of air conditioning system, and medium
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Solution Overview
Problem
Existing air conditioning systems face inaccuracies in freezing prevention due to uneven refrigerant flow distribution and the lack of communication between indoor and outdoor units, leading to potential evaporator damage and inefficient operation.
Innovation Solution
A method that compensates real-time return air parameters on the low-pressure side of the outdoor unit based on ambient temperature, allowing for accurate determination of freezing risk without requiring communication between units, and controls the system to enter a freezing prevention mode to prevent evaporator freezing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If evaporator temperature is used for freezing prevention control, then freezing prevention can be achieved, but measurement accuracy deteriorates due to uneven refrigerant flow distribution causing the detected temperature to not reflect the actual lowest temperature
Solution Approach 1:
The patent uses return air temperature as an intermediary parameter to indirectly assess evaporator freezing risk. Instead of directly measuring evaporator temperature (which is inaccurate due to uneven refrigerant flow), the system measures return air temperature and compares it against threshold values to determine freezing risk, thereby solving the measurement precision problem while maintaining control reliability
Solution Approach 2:
The patent replaces direct evaporator temperature measurement (mechanical/physical sensing at the evaporator location) with return air temperature measurement (environmental sensing). This substitution avoids the measurement accuracy issues caused by uneven refrigerant flow in the evaporator while still enabling effective freezing prevention control
2Ease of operation
If indoor unit mainboard controls the air conditioner operation, then system control can be achieved, but device complexity increases due to required communication between indoor and outdoor units
Solution Approach 1:
The patent extracts the freezing prevention control function from the indoor unit mainboard and relocates it to the outdoor unit. By moving the control logic to where the temperature sensor is located (outdoor unit), the system eliminates the need for complex communication between indoor and outdoor units, simplifying the overall device complexity while maintaining full control capability
Solution Approach 2:
The outdoor unit performs freezing prevention control autonomously using its own temperature sensor and control logic. The outdoor unit monitors return air temperature and independently determines when to activate freezing prevention measures, without requiring instructions or data exchange with the indoor unit, thereby reducing communication system complexity
3Reliability
If evaporator temperature monitoring is used, then freezing detection can be performed, but loss of information occurs because the detected temperature does not reflect the actual lowest temperature of the evaporator
Solution Approach 1:
The patent introduces return air temperature as an intermediary measurement that better correlates with actual evaporator freezing conditions. Since return air temperature reflects the thermal state of air that has passed through the evaporator, it provides more accurate information about the lowest temperature conditions in the evaporator compared to direct evaporator temperature sensing
Solution Approach 2:
The patent changes the measured parameter from evaporator temperature (which suffers from measurement inaccuracies) to return air temperature (which provides more reliable information). By monitoring return air temperature and comparing it to threshold values, the system accurately detects freezing conditions without losing critical temperature information
Data Source
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AI summary
The present invention provides a method and device for controlling freezing prevention during refrigeration of an air conditioning system, and a medium. The method includes the following steps: a preset step: presetting a return air parameter compensation quantity according to an outdoor ambient temperature; a detection step: detecting a real-time return air parameter on a low-pressure side of the air conditioning system in a refrigeration mode; a comparison step: calculating a corrected return air parameter according to the sum of the real-time return air parameter and the corresponding return air parameter compensation quantity, and comparing whether the corrected return air parameter is less than a first return air parameter threshold; and a control step: controlling the air conditioning system to enter a freezing prevention protection mode if the corrected return air parameter is less than the first return air parameter threshold. According to the present invention, the accuracy of freezing prevention determination is improved, and the interference by bias flow and the like is avoided; and the start and stop of a compressor (11) can be controlled to realize the freezing prevention protection without the need for the communication between an indoor unit and an outdoor unit.