Compressor Heating Control Using Refrigerant Temperature Change Rate
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Solution Overview
Problem
Existing air-conditioning apparatuses face issues with excessive heating and wasteful power consumption due to inefficient methods for preventing refrigerant stagnation in compressors, leading to lubricant degradation and potential compressor burnout, even when refrigerant does not stagnate.
Innovation Solution
An air-conditioning apparatus with a refrigerant circuit, temperature detection means, and control means that calculates the refrigerant temperature change rate and adjusts heating accordingly to prevent excessive heating and reduce power consumption by matching the heating amount to the compressor with the refrigerant temperature change rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compressor is heated to prevent refrigerant stagnation, then refrigerant condensation is prevented, but power consumption increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the heating amount based on the refrigerant temperature change rate. Instead of using fixed heating, the system modifies the heating parameter (amount of heating) according to the actual temperature变化 conditions, thereby preventing refrigerant stagnation only when necessary and reducing unnecessary power consumption.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the refrigerant temperature change rate and using this information to adjust the heating amount. The control unit receives temperature data, calculates the change rate, and accordingly regulates the heating element, creating a closed-loop system that optimizes power consumption while preventing refrigerant accumulation.
2Reliability
If the compressor is heated with constant heating amount, then refrigerant stagnation is prevented, but excessive heating occurs when refrigerant temperature is stable
Solution Approach 1:
The patent applies dynamics by transitioning from static constant heating to dynamic variable heating. The heating amount is continuously adjusted based on the refrigerant temperature change rate, making the heating system adaptive to changing conditions. When temperature is stable (change rate approaches zero), heating is reduced or stopped, preventing excessive temperature rise.
Solution Approach 2:
The system changes the heating parameter dynamically based on the refrigerant temperature change rate. When the temperature change rate is high, heating is increased to prevent stagnation; when the temperature is stable, heating is reduced, thereby avoiding excessive compressor temperature while maintaining reliability.
3Device complexity
If heating is applied based on outside air temperature only, then control is simplified, but heating occurs even when refrigerant does not condense
Solution Approach 1:
The patent uses feedback from the actual refrigerant temperature (or temperature proxy) to control heating, rather than relying solely on outside air temperature. The control unit continuously monitors the temperature change rate of the refrigerant and adjusts heating accordingly, ensuring energy is consumed only when refrigerant condensation is actually occurring or likely to occur.
Solution Approach 2:
The patent replaces the simple outside air temperature-based control mechanism with a more sophisticated control system that uses actual refrigerant temperature feedback. This substitution eliminates wasteful heating by base d on real refrigerant conditions rather than environmental assumptions, reducing energy loss while accepting increased control complexity.
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 condensation and stagnation in the compressor, maintaining lubricant concentration and reducing power consumption by ensuring the heating amount is proportional to the refrigerant temperature change rate, thus avoiding unnecessary heating.
Implementation Method 1
Another method is to apply a high-frequency, low-voltage current to a coil of the motor in the compressor. With this method, without rotating the motor, the compressor is heated with Joule heat generated in the coil.
Data Source
AI summary
While a compressor is stopped, a change rate of a refrigerant temperature per predetermined time is calculated on the basis of a value detected by a refrigerant temperature sensor, and a heating amount from a compressor heating unit to the compressor is made proportional to the change rate of the refrigerant temperature.