Working fluid composition and refrigerator
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Solution Overview
Problem
Existing refrigerating machine working fluid compositions using unsaturated hydrofluorocarbon refrigerants like HFO-1234yf lack stability and refrigerant dissolution viscosity, necessitating improved formulations.
Innovation Solution
A novel working fluid composition comprising a refrigerating machine oil with specific base oils (polyol ester and polyvinyl ether) and additives (epoxy-based acid scavenger, phenol-based antioxidant, and phosphorus-containing antiwear agent) is developed, with a defined refrigerant fraction and P/E ratio, enhancing refrigerant dissolution viscosity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HFO-1234yf alone is used as refrigerant, then the working fluid composition has lower refrigerant dissolution viscosity, but the stability is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the refrigerating machine oil by specifying particular base oils (polyol ester with specific hydroxyl value range, polyvinyl ether with specific molecular weight range) and additive combinations (epoxy-based acid scavenger, phenol-based antioxidant, phosphorus-containing antiwear agent) to achieve both improved stability and adequate refrigerant dissolution viscosity
Solution Approach 2:
The patent creates a composite refrigerating machine oil by combining multiple components: base oil (polyol ester or polyvinyl ether), epoxy-based acid scavenger, phenol-based antioxidant, and phosphorus-containing antiwear agent. This composite formulation achieves synergistic effects that simultaneously improve stability and maintain refrigerant dissolution viscosity
2Productivity
If the refrigerant fraction is increased, then the cooling performance is improved, but the refrigerant dissolution viscosity decreases
Solution Approach 1:
The patent optimizes the refrigerant fraction parameter within the range of 60-80% by mass and adjusts the base oil properties (hydroxyl value 0.5-10 mg KOH/g for polyol ester, molecular weight 500-2000 for polyvinyl ether) to maintain adequate refrigerant dissolution viscosity while achieving desired cooling performance
3Device complexity
If conventional refrigerating machine oil is used, then the formulation is simple, but the stability with HFO-based refrigerants is insufficient
Solution Approach 1:
The patent develops a composite refrigerating machine oil containing base oil (polyol ester or polyvinyl ether), epoxy-based acid scavenger, phenol-based antioxidant, and phosphorus-containing antiwear agent. This multi-component formulation provides excellent stability with HFO-based refrigerants while maintaining practical formulation complexity
Solution Approach 2:
The epoxy-based acid scavenger acts as an intermediary that neutralizes acidic degradation products formed during refrigerant-oil interaction, thereby preventing oil degradation and maintaining system stability. The phenol-based antioxidant similarly mediates by preventing oxidative degradation
Data Source
AI summary
A working fluid composition containing a refrigerating machine oil and a refrigerant containing HFO-1132(E) and HFO-1234yf, wherein a refrigerant fraction at 80° C. and 2.5 MPa is 80% by mass or less, and the refrigerating machine oil contains a base oil, an epoxy-based acid scavenger, a phenol-based antioxidant, and a phosphorus-containing antiwear agent, and wherein a P/E ratio is 0.2 or more and 1.1 or less:P/E ratio=(WP×NP/MP)/(WE×NE/ME)wherein WP represents a content of the phosphorus-containing antiwear agent, NP represents a number of a phosphorus atom, MP represents a molecular weight of the phosphorus-containing antiwear agent, WE represents a content of the epoxy-based acid scavenger, NE represents a number of an epoxy group, and ME represents a molecular weight of the epoxy-based acid scavenger.