Heat Cycle Refrigerant Composition for Low-GWP HFO Lubricity
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Solution Overview
Problem
Current heat cycle systems using hydrofluorolefins (HFOs) face instability and reduced lubricity under compression and heating, leading to inferior performance compared to saturated hydrofluorocarbons, while also having high global warming potential (GWP).
Innovation Solution
A composition for a heat cycle system incorporating an unsaturated fluorinated hydrocarbon compound with a refrigerant oil, specifically a polyol ester or polyvinyl ether refrigerant oil, to enhance lubricity and maintain low GWP and excellent cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hydrofluoroolefin (HFO) is used as a working fluid, then global warming potential is reduced and ozone layer influence is minimized, but stability under compression and heating deteriorates and lubricating properties decrease
Solution Approach 1:
The patent combines HFO (unsaturated fluorinated hydrocarbon) with specific refrigerant oils (polyol ester or polyvinyl ether) to create a composite working fluid system. This composite approach allows the HFO to provide low GWP while the refrigerant oil compensates for the reduced lubricating properties and enhances stability under compression and heating conditions.
Solution Approach 2:
The patent specifies precise parameter ranges for the refrigerant oil components, including viscosity at 40°C (5-200 mm²/s), viscosity at 100°C (1-100 mm²/s), and breakdown voltage (≥25 kV). By controlling these parameters, the system maintains optimal performance and stability while using HFO as the base working fluid.
2Object-affected harmful factors
If hydrofluoroolefin (HFO) is used as a working fluid, then global warming potential is reduced, but lubricating properties deteriorate
Solution Approach 1:
The patent introduces refrigerant oil (polyol ester or polyvinyl ether) as an intermediary substance that mediates between the HFO working fluid and the system components. The refrigerant oil provides the necessary lubricating properties that HFO lacks, while being compatible with the low-GWP HFO base fluid.
Solution Approach 2:
The working fluid system is formulated as a composite mixture of HFO and specific refrigerant oils, where the refrigerant oil component (5-50 mass%) provides lubricating properties that compensate for the inherent deficiencies of HFO, enabling the system to maintain both environmental benefits and operational reliability.
3Ease of operation
If conventional refrigerant oil is used with HFO, then lubricating properties may be maintained, but cycle performance deteriorates
Solution Approach 1:
The patent specifies optimized parameter ranges for the refrigerant oil to simultaneously achieve good lubricating properties and excellent cycle performance. The viscosity at 40°C is controlled at 5-200 mm²/s and at 100°C at 1-100 mm²/s, with breakdown voltage ≥25 kV. These parameter optimizations ensure both lubrication and thermodynamic efficiency.
Solution Approach 2:
The patent differentiates between different functional requirements of the refrigerant oil: viscosity control for lubrication, breakdown voltage for electrical insulation, and chemical compatibility for cycle performance. By optimizing each local property independently within specified ranges, the system achieves overall superior performance.
Data Source
AI summary
A composition for a heat cycle system and a heat cycle system employing the composition are provided. The composition has favorable lubricating properties and contains a working fluid for heat cycle and a refrigerant oil. The working fluid has a low global warming potential and can replace R410A. The working fluid contains an unsaturated fluorinated hydrocarbon compound having a specific structure. The refrigerant oil has a breakdown voltage of at least 25 kV, a hydroxyl value of at most 0.1 mgKOH/g, and a kinematic viscosity at 40° C. of from 5 to 200 mm2/s and a kinematic viscosity at 100° C. of from 2 to 30 mm2/s.