Working fluid for heat cycle
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Solution Overview
Problem
The existing working fluids for heat cycles, such as hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs), have environmental concerns including ozone depletion and global warming potential, and the use of hydrofluoroolefins (HFOs) like HCFO-1224yd, which are less stable due to impurities and isomer mixtures, poses challenges for stability and productivity.
Innovation Solution
A working fluid comprising (Z)-1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd(Z)) with trace components at less than 1.5 mass% impurities, specifically selected from a group including HCFC-225cb, HFC-254eb, and others, to enhance stability and cycle performance while minimizing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If HCFO-1224yd containing impurities and isomer mixtures is used as working fluid, then environmental performance is improved (low ODP and GWP), but stability is deteriorated
Solution Approach 1:
The patent extracts and removes the E-isomer of HCFO-1224yd from the mixture, retaining only the Z-isomer. This selective extraction eliminates the unstable component while preserving the environmentally beneficial properties of the working fluid, thereby resolving the contradiction between environmental performance and stability.
Solution Approach 2:
The patent changes the compositional parameter by specifying that the working fluid contains more than 98.5 mass% of the Z-isomer of HCFO-1224yd. This parameter change ensures high stability while maintaining the low ODP and GWP characteristics, thus resolving the contradiction between stability and environmental performance.
2Object-affected harmful factors
If HCFO-1224yd is used as working fluid, then environmental performance is improved, but productivity is deteriorated due to complex purification requirements
Solution Approach 1:
The patent employs a purification process that selectively removes the E-isomer impurity from the HCFO-1224yd mixture. By targeting only the specific unstable component rather than performing extensive purification of all impurities, the process maintains high productivity while achieving the necessary stability for commercial use.
Solution Approach 2:
The patent establishes a clear compositional threshold (>98.5 mass% Z-isomer) that balances purification effort with performance requirements. This parameter specification enables efficient production by defining a practical purity target that ensures stability without requiring excessively complex or time-consuming purification processes.
3Ease of manufacture
If mixture of Z-isomer and E-isomer of HCFO-1224yd is used, then production cost is reduced, but stability is deteriorated
Solution Approach 1:
The patent removes only the E-isomer component from the mixture while retaining the Z-isomer. This selective extraction approach is more cost-effective than complete purification methods, as it targets only the specific unstable component, thereby maintaining ease of manufacture while achieving the required stability.
Solution Approach 2:
The patent defines a practical purity specification (>98.5 mass% Z-isomer) that balances manufacturing cost with stability requirements. This parameter change establishes a cost-effective production target that eliminates the unstable E-isomer while avoiding the excessive costs associated with achieving absolute purity.
Data Source
AI summary
There is provided a working fluid for heat cycle that uses (Z)-1-chloro-2,3,3,3-tetrafluoropropane (HCFO-1224yd(Z)) which has a less impact on the ozone layer, has a less impact on global warming, and has excellent cycle performance, the working fluid for heat cycle having sufficiently ensured stability and having high productivity. The working fluid for heat cycle contains HCFO-1224yd(Z) and an impurity, wherein the impurity includes a specific trace component, and a total content ratio of the trace component to a total amount of the working fluid is less than 1.5 mass %.