Method for controlling freezing of indoor unit, outdoor unit and/or unit connection pipe of air conditioner
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Solution Overview
Problem
Air conditioners often experience freezing issues in the indoor unit, outdoor unit, and connection pipes due to low ambient temperatures, long piping, and Freon deficiencies, leading to poor cooling effects, water leakage, and pipe cracks, which existing temperature and pressure-based control methods fail to adequately address.
Innovation Solution
A control method that adjusts the compressor frequency based on the suction temperature of the outdoor unit, using preset temperature thresholds to prevent freezing by decreasing, maintaining, or increasing compressor frequency, and incorporating ambient temperature adjustments to optimize anti-freezing protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indoor unit coil temperature sensor or pressure switch is used for anti-freezing control, then freezing protection is provided, but the control system is prone to sensor failure and inaccurate detection
Solution Approach 1:
The patent uses suction temperature as an intermediary parameter to indirectly monitor the thermal state of the indoor unit and piping system. Instead of directly measuring coil temperature or pressure, the system measures suction temperature at the compressor inlet, which reflects the overall system thermal condition and enables anti-freezing control without relying on fragile local sensors
Solution Approach 2:
The patent replaces the mechanical/physical sensor-based detection system (temperature sensors and pressure switches) with a computational control system that calculates system state based on suction temperature measurements and operational parameters, reducing dependence on physical sensors that are prone to failure
2Adaptability or versatility
If long piping connection is used, then installation flexibility is improved, but pressure loss increases causing freezing of suction pipe and outdoor unit
Solution Approach 1:
The patent implements a feedback control mechanism where suction temperature is continuously monitored and used to adjust compressor operation. The controller compares suction temperature against preset thresholds and adjusts compressor frequency accordingly, creating a closed-loop system that adapts to varying piping conditions and prevents freezing regardless of pipe length
Solution Approach 2:
The patent transitions from static pressure-based control to dynamic temperature-based control. The system continuously adjusts compressor operating frequency based on real-time suction temperature measurements, enabling adaptive response to changing system conditions caused by various piping configurations
3Reliability
If indoor unit coil temperature sensor fails or is incorrectly connected, then temperature detection becomes inaccurate, but anti-freezing protection must still function
Solution Approach 1:
The patent eliminates dependence on the indoor unit coil temperature sensor by using suction temperature as an alternative intermediary measurement. Suction temperature serves as a proxy indicator of system thermal state, allowing the control system to infer indoor unit conditions without directly measuring coil temperature
Solution Approach 2:
The system uses readily available suction temperature data from the compressor inlet to perform anti-freezing control, making the system self-sufficient and not dependent on additional sensors or complex measurement systems that could fail
Data Source
AI summary
A control method for an air conditioner comprising a compressor and an outdoor unit, wherein the control method includes: obtaining a suction temperature of the outdoor unit; and selectively adjusting the frequency of the compressor according to the suction temperature of the outdoor unit.