Compressor Preheating Control for High-Drop Air Conditioners
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Solution Overview
Problem
In air conditioners with high-drop installations, the lubricating oil in the compressor is difficult to return due to evaporation of refrigerant, leading to increased losses in internal winding coils and motors, and issues with low-pressure protection and defrosting signal feedback, especially under low-temperature conditions.
Innovation Solution
A control method that preheats the compressor by setting specific conditions for the crankshaft heating belt, including detecting ambient and compressor temperatures to determine when to turn on or off the heating belt, ensuring the compressor is preheated before starting, and managing electrical heating to maintain proper lubrication and prevent refrigerant evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compressor is started directly under low-temperature conditions in high-drop mode, then the starting process is simple and quick, but the refrigerant in the cavity evaporates quickly, taking the lubricating oil away from the compressor, leading to insufficient lubrication and increased losses
Solution Approach 1:
The system performs preliminary detection of installation conditions (high-drop mode identification) and preheats the compressor cavity before starting the compressor. This preliminary action prevents refrigerant evaporation from carrying away lubricating oil during the starting process, ensuring proper lubrication from the beginning of compressor operation.
Solution Approach 2:
The system continuously detects outdoor ambient temperature, compressor exhaust temperature, and operating duration, and uses this feedback information to dynamically control the crankshaft heating belt and compressor startup. The feedback mechanism ensures the compressor is preheated to the appropriate temperature before starting, preventing oil carry-away while avoiding excessive preheating.
2Reliability
If the crankshaft heating belt is turned on continuously to ensure proper lubrication, then the lubricating oil is protected from being carried away, but the energy consumption increases and the compressor may overheat
Solution Approach 1:
The crankshaft heating belt operates periodically rather than continuously. It is activated only when specific conditions are met (high-drop mode detected, low ambient temperature, before compressor startup), and turned off after a predetermined operating duration or when temperature thresholds are reached. This periodic operation reduces energy consumption while maintaining adequate lubrication protection.
Solution Approach 2:
The system changes the operating parameters of the crankshaft heating belt based on detected conditions, including activation timing, operating duration, and temperature thresholds. By dynamically adjusting these parameters rather than operating at fixed settings, the system minimizes energy consumption while ensuring adequate preheating for reliable lubrication.
3Reliability
If the compressor is prohibited from starting in non-cooling mode when powered on for the first time, then the lubricating oil is protected from being carried away, but the heating function cannot be provided to the user
Solution Approach 1:
The system introduces an intermediary electrical heating device that can operate independently of the compressor. When the compressor is prohibited from starting (first-power-on in non-cooling mode at low temperature), the electrical heating device provides heating functionality to users. This intermediary solution maintains user serviceability while protecting the compressor from damaging startup conditions.
Solution Approach 2:
The system performs preliminary detection of the first-power-on condition and appropriately restricts compressor startup while activating alternative heating methods. This preliminary control action prevents compressor damage while ensuring users still receive heating service through the electrical heating device during the initial warm-up period.
4Device complexity
If the outdoor unit only provides defrosting signal feedback without temperature controller control, then the system structure is simple, but when the outdoor unit is not started, there is no signal feedback to the indoor unit, resulting in electrical heating being unable to operate normally
Solution Approach 1:
The outdoor unit's control signal system is enhanced to provide multiple functions: it not only provides defrosting signal feedback but also provides operational status signals to the indoor unit regardless of whether the outdoor unit is running. This multi-functional signal system ensures the indoor unit can make informed decisions about electrical heating operation based on comprehensive status information.
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 effectively prevents refrigerant evaporation from taking away lubricating oil, ensuring stable compressor operation, reducing energy consumption, and maintaining user experience by ensuring proper heating and cooling functions even in low-temperature environments.
Implementation Method 1
a crankshaft heating belt is provided at the bottom of the compressor... turning on the crankshaft heating belt... preheating the compressor
Implementation Method 2
the refrigerant in the cavity will evaporate quickly, taking the lubricating oil away from the compressor
Data Source
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AI summary
The present invention provides a control method and device suitable for an air conditioner in a high-drop mode. The method includes: detecting an outdoor ambient temperature and a compressor exhaust temperature in real time; determining whether the air conditioner meets a preheating condition; if the air conditioner does not meet the preheating condition, not turning on a crankshaft heating belt (11); if the air conditioner meets the preheating condition, turning on the crankshaft heating belt (11); and determining whether the air conditioner is in a high-drop mode, and if the air conditioner is in the high-drop mode, determining whether the air conditioner is in a cooling mode; controlling whether to turn off the crankshaft heating belt (11) based on different determining conditions corresponding to whether the air conditioner is in the cooling mode; during turning on of the crankshaft heating belt (11), determining whether the air conditioner meets a compressor turning-on condition, where the compressor turning-on condition includes: in the high-drop mode, the air conditioner is in the cooling mode; or in the high-drop mode, the air conditioner is in a non-cooling mode, and the outdoor ambient temperature is higher than a first preset ambient temperature. The present invention enables a compressor (1) to be fully preheated by setting turning-off conditions of the crankshaft heating belt (11) in different modes, to solve a problem of difficulty in oil return.