Compressor Oil Preheating via Capacitive Sensor Dielectric Heating
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Solution Overview
Problem
Existing preheating methods for compressors in refrigerating cycles are inefficient, as they either require costly external heaters or consume excessive power through motor energization, leading to poor lubricant oil heating efficiency.
Innovation Solution
A capacitive oil surface sensor and an oscillator circuit apply high-frequency voltage directly to the lubricant oil, utilizing dielectric heating to efficiently warm the oil without additional heating components, reducing power consumption and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an external heater is mounted on the compressor casing to heat the lubricant oil, then the lubricant oil can be heated, but the heating efficiency is poor and enormous power and time are required
Solution Approach 1:
The patent introduces a capacitor as an intermediary component between the power supply and the lubricant oil. The capacitor is filled with lubricant oil and subjected to high-frequency voltage, which generates heat through dielectric loss. This intermediary approach allows direct heating of the lubricant oil without requiring external heaters, significantly improving heating efficiency and reducing power consumption.
2Temperature
If the motor is open-phase energized to heat the lubricant oil, then the lubricant oil can be heated, but power is consumed by both the coil and power module resulting in great power loss
Solution Approach 1:
The patent extracts the heating function from the motor system and power module, creating a separate dedicated heating system using a capacitor and high-frequency voltage source. This separation eliminates the power losses associated with using the motor for heating purposes, as the new system only consumes power for capacitive heating without the additional losses from motor control circuits and power modules.
3Temperature
If the motor coil heat is transferred to lubricant oil by air propagation, then the lubricant oil can be heated, but it takes time to raise the temperature resulting in poor efficiency
Solution Approach 1:
The patent replaces the mechanical/thermal conduction method (motor coil heating through air propagation) with an electromagnetic field-based heating method. By applying high-frequency voltage to the capacitor filled with lubricant oil, heat is generated directly within the oil through dielectric loss, eliminating the need for heat transfer through air and significantly reducing heating time while improving efficiency.
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 method efficiently heats the lubricant oil with lower power consumption, preventing refrigerant stagnation and oil loss during compressor halts, while simplifying the system and reducing costs.
Implementation Method 1
by applying the high-frequency voltage to the capacitive oil surface sensor, the lubricant oil, which is a dielectric, can be heated by dielectric heating
Data Source
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AI summary
A preheater for a compressor that is capable of heating a lubricant oil efficiently with smaller power is provided. A preheater (50) for a compressor (15) includes: a capacitive oil surface sensor (46) that is provided at a compressor (15) used in a refrigerating cycle, and detects an oil surface of a lubricant oil A in the compressor (15); and a power supply unit (45) that applies high-frequency voltage to the oil surface sensor (46).