Preheater for compressor
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Solution Overview
Problem
Existing preheating methods for compressors in refrigerating cycles, such as using external heaters or motor energization, are inefficient and costly, leading to significant power consumption and prolonged heating times for lubricant oil, which can result in refrigerant stagnation and oil loss.
Innovation Solution
A preheater system utilizing a capacitive oil surface sensor and an oscillator circuit to apply high-frequency voltage directly to the lubricant oil, enabling dielectric heating without the need for additional heating elements, thus reducing power consumption and heating time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external heater is mounted on the compressor casing to heat the lubricant oil, then the lubricant oil can be heated during compressor halt, but the heating efficiency is poor and enormous power and time are required
Solution Approach 1:
The patent introduces a capacitive sensor as an intermediary element that serves dual purposes: detecting oil level and enabling dielectric heating of the lubricant oil. This mediator allows direct energy transfer to the oil without requiring external heaters mounted on the compressor casing, thereby improving heating efficiency and reducing power consumption while maintaining the reliability of preventing refrigerant stagnation.
2Temperature
If the motor is open-phase energized to heat the lubricant oil, then the coil generates heat, but power is consumed by both the coil and power module resulting in great power loss
Solution Approach 1:
The capacitive sensor, originally designed for oil level detection, is utilized to perform dielectric heating of the lubricant oil during compressor halt. This self-service approach eliminates the need for separate heating systems or open-phase motor energization, as the sensor itself generates the necessary heat through dielectric loss when subjected to high-frequency voltage, thereby reducing power loss while maintaining effective oil temperature control.
3Temperature
If the motor coil heat is transferred to the lubricant oil by air propagation, then the lubricant oil is heated, but it takes time to raise the temperature resulting in poor efficiency
Solution Approach 1:
The patent replaces the mechanical/thermal convection system (air propagation from motor coil to oil) with a direct dielectric heating mechanism. By applying high-frequency voltage to the capacitive sensor immersed in the lubricant oil, heat is generated directly within the oil through dielectric loss, eliminating the time-consuming air propagation step and achieving rapid temperature rise with high 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 solution efficiently heats the lubricant oil with lower power consumption and faster heating times, 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
AI summary
A preheater for a compressor that is capable of heating a lubricant oil efficiently with smaller power is provided. A preheater for a compressor includes: a capacitive oil surface sensor that is provided at a compressor used in a refrigerating cycle, and detects an oil surface of a lubricant oil A in the compressor; and a power supply unit that applies high-frequency voltage to the oil surface sensor.