Refrigerant Reservoir Sensor Shielding for Accurate Liquid Level Detection
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Solution Overview
Problem
In refrigeration cycle apparatuses, the increased flow velocity of gas refrigerant can cause heat generating elements to reach temperatures similar to those immersed in liquid refrigerant, leading to inaccurate liquid level detection due to the inability to differentiate between the two states effectively.
Innovation Solution
The implementation of a liquid level detection sensor system with multiple heat generating elements and a controller that calculates temperatures based on resistance values, ensuring accurate detection by positioning the sensor outside the core region of high refrigerant velocity and using shielding or fins to mitigate refrigerant impact, thereby maintaining detection accuracy even with increased refrigerant circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the refrigerant circulating amount is increased to improve cooling performance, then the cooling efficiency is improved, but the flow velocity of gas refrigerant increases causing the heat generating element temperature to decrease and become similar to the temperature when immersed in liquid refrigerant, leading to decreased liquid level detection accuracy
Solution Approach 1:
The patent introduces a new spatial dimension by positioning the liquid level detection sensor at a specific location outside the core region where high-velocity gas refrigerant flows. Instead of trying to improve temperature differentiation along the existing thermal detection dimension, the solution moves the sensor to a different spatial position (radial distance from the refrigerant flow path) where the interfering thermal effects are minimized, thereby maintaining detection accuracy while allowing high refrigerant circulation for improved cooling efficiency.
Solution Approach 2:
The patent uses the spatial positioning of the sensor as an intermediary mechanism to mediate between the conflicting requirements of high refrigerant flow (for cooling efficiency) and accurate temperature detection (for liquid level detection). By placing the sensor in an intermediate zone outside the core high-velocity flow region, the sensor is exposed to a moderated thermal environment that preserves temperature differentiation capability while allowing the main refrigerant circulation to operate at high efficiency.
2Measurement precision
If multiple heat generating elements are used to improve detection accuracy, then the liquid level detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the detection function into multiple heat generating elements positioned at different locations. Each element independently detects thermal conditions at its specific position, and the controller integrates these multiple detection signals to determine the liquid level. This segmented approach improves detection accuracy by capturing spatial temperature variations while keeping each individual sensor element relatively simple in structure.
Solution Approach 2:
The heat generating elements serve multiple functions: they generate heat for thermal detection, and their temperature changes serve as the detection signal for liquid level measurement. By making the same component perform both heating and sensing functions, the patent avoids adding separate heating elements and sensors, thereby improving detection capability without proportionally increasing device 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 configuration suppresses the decrease in detection accuracy caused by increased refrigerant flow velocity, ensuring precise liquid level detection and preventing refrigerant overflow or leakage, enhancing the reliability of the refrigeration cycle apparatus.
Implementation Method 1
a heat generating element 201a to 201d and a temperature detecting element 204a to 204d. The liquid level detection sensor 20 employs only the heat generating element 201a to 201d as both the heat generating unit and the sensor unit
Implementation Method 2
The controller 50 calculates temperatures of the heat generating elements 201a to 201d of the liquid level detection sensor 20 from resistance values
Implementation Method 3
When the flow velocity of the gas refrigerant increases, the gas refrigerant acts so as to remove an increased amount of heat of the heat generating element. Specifically, the gas refrigerant acts so as to increase the amount of heat rejected from the heat generating element.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Provided is a refrigeration cycle apparatus including: a refrigerant circuit formed by connecting, by a refrigerant pipe, a compressor, a condenser, an expansion device, an evaporator and a liquid reservoir; a liquid level detection sensor including a plurality of heat generating units and a plurality of temperature detection units, the heat generating units being paired with the temperature detection units, and provided in the liquid reservoir, the liquid level detection sensor being configured to detect a liquid level of a refrigerant accumulated in the liquid reservoir, based on a temperature of each of the heat generating units, in which the liquid reservoir includes a container for accumulating the refrigerant, an inlet pipe connected to the refrigerant circuit and configured to allow a portion of the refrigerant flowing out of the container to flow into the container, and in which in the container, a shielding portion is provided between an discharge outlet for the refrigerant of the inlet pipe and the liquid level detection sensor, to prevent the portion of the refrigerant flowing out of the discharge outlet from directly coming into contact with the liquid level detection sensor.