Refrigeration cycle device
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Solution Overview
Problem
Sulfur-based odorants dissolve in polar refrigeration oils, reducing their circulation in refrigerant circuits and making refrigerant leakage undetectable by smell, due to high polarity and electronegativity of polyalkylene glycol oils.
Innovation Solution
A refrigeration cycle device with a hydrocarbon refrigerant and sulfur-based odorant, using polyalkylene glycol oil with a specific oxygen-to-carbon atom ratio of 0.50 or less in its molecular structure to minimize odorant dissolution and enhance detectability of refrigerant leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyalkylene glycol refrigeration oil is used to reduce refrigerant dissolution, then refrigeration cycle performance is improved, but sulfur-based odorant dissolution increases making refrigerant leakage undetectable
Solution Approach 1:
The patent changes the molecular structure parameters of polyalkylene glycol by controlling the ratio of oxygen atoms to carbon atoms (O/C ratio) to be 0.50 or less. This parameter modification reduces the polarity of the refrigeration oil, thereby decreasing its affinity for sulfur-based odorants and preventing their dissolution, while maintaining adequate refrigerant solubility for cycle performance
Solution Approach 2:
The patent uses composite refrigeration oil formulated from polyalkylene glycol with specific molecular structure characteristics (O/C ratio ≤ 0.50) combined with appropriate additives. This composite material achieves a balance between refrigerant solubility for performance and reduced odorant dissolution for detectability
2Difficulty of detecting and measuring
If sulfur-based odorant is added to hydrocarbon refrigerant to enable smell detection, then refrigerant leakage detectability is improved, but odorant dissolution in refrigeration oil reduces circulation amount
Solution Approach 1:
By modifying the molecular structure of polyalkylene glycol (reducing O/C ratio to 0.50 or less), the patent changes the solubility parameters of the refrigeration oil. This reduces the dissolution of sulfur-based odorants into the oil, ensuring sufficient odorant remains in the refrigerant circuit for effective smell detection
Solution Approach 2:
The patent uses polyalkylene glycol with specific molecular characteristics as an intermediary medium that mediates between refrigerant solubility requirements and odorant dissolution prevention. The controlled O/C ratio creates optimal interaction properties that allow refrigerant circulation while minimizing odorant absorption
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
The solution effectively suppresses the dissolution of sulfur-based odorants in polyalkylene glycol oils, making refrigerant leakage recognizable by smell, while maintaining low Global Warming Potential and flammability.
Implementation Method 1
sulfur-based odorants such as THT have polarity due to the bias of charge in the molecule; thus, when a refrigeration oil having high polarity is used, the sulfur-based odorant is dissolved in the refrigeration oil in a compressor
Implementation Method 2
polyalkylene glycol contain a large amount of oxygen (O), which is an element having a large electronegativity in the molecular structure, they are refrigeration oils having high polarity and dissolve a large amount of sulfur-based odorants
Data Source
AI summary
A refrigeration cycle device including a refrigerant circuit including a compressor, wherein a refrigerant is enclosed in refrigerant circuit, the refrigerant contains a hydrocarbon having 1 to 4 carbon atoms and a sulfur-based odorant, compressor is filled with a refrigeration oil, the refrigeration oil contains polyalkylene glycol, and a ratio of a number of oxygen atoms to a number of carbon atoms in a molecular structure of polyalkylene glycol is 0.50 or less.