Centrifugal Compressor Heat-Transfer Fluid Composition for Low-GWP Retrofit
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Solution Overview
Problem
Current vapor compression systems using HFC-134a as a heat transfer fluid face challenges in replacing it with alternatives that have a lower global warming potential (GWP) without degrading the performance of centrifugal compressors, particularly in maintaining or improving efficiency and avoiding the need for compressor modifications.
Innovation Solution
A process and installation using a heat transfer fluid comprising a mixture of 2,3,3,3-tetrafluoropropene, 1,3,3,3-tetrafluoropropene, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane, and 3,3,3-trifluoropropene, which maintains the Mach number and compression ratio similar to HFC-134a, ensuring equivalent compressor performance and potentially reducing rotational speed to decrease wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If HFC-134a is replaced with alternative heat transfer fluids having lower GWP, then environmental performance is improved, but compressor efficiency and performance may deteriorate
Solution Approach 1:
The invention changes the physical and chemical parameters of the heat transfer fluid by using a specific composition of HFO-1234yf and HFO-1234ze isomers with controlled ratios. This parameter change allows achieving lower GWP while maintaining the fluid's thermodynamic properties (density, viscosity, speed of sound) within ranges that preserve compressor efficiency and operating characteristics.
Solution Approach 2:
The invention uses a composite approach by combining HFO-1234yf and HFO-1234ze isomers in specific proportions rather than using a single compound. This composite fluid composition enables optimization of multiple properties simultaneously - achieving low GWP while maintaining compatibility with centrifugal compressor operating parameters and avoiding efficiency degradation.
2Object-affected harmful factors
If heat transfer fluid composition is modified to reduce GWP, then environmental constraints are satisfied, but system adaptability and operating conditions may be compromised
Solution Approach 1:
The invention carefully controls the compositional parameters of the heat transfer fluid (specifically the ratio of HFO-1234yf to HFO-1234ze isomers) to maintain key physical properties within acceptable ranges. This allows the system to adapt to the new fluid composition without requiring modifications to the centrifugal compressor or other system components, thereby preserving system versatility while meeting environmental requirements.
3Object-affected harmful factors
If alternative heat transfer fluids are used in centrifugal compressors, then environmental performance improves, but compressor wear and operational reliability may worsen
Solution Approach 1:
The invention selects and controls the physical parameters of the alternative heat transfer fluid (density, viscosity, speed of sound) to match the operating conditions for which the centrifugal compressor was originally designed. By maintaining these parameters within specific ranges, the fluid exerts appropriate mechanical stresses on the compressor components, avoiding excessive wear and ensuring reliable operation while achieving lower GWP.
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 proposed solution allows for the replacement of HFC-134a with a lower GWP fluid, maintaining or improving compressor performance without requiring compressor changes, and reducing energy consumption by adjusting the fluid composition to match the original operating conditions.
Implementation Method 1
the vaporization of the fluid at low pressure (in which the fluid absorbs heat)
Implementation Method 2
the compression of the vaporized fluid to a high pressure
Implementation Method 3
the condensation of the vaporized fluid to liquid at high pressure (in which the fluid releases heat)
Implementation Method 4
the expansion of the fluid in order to complete the cycle
Data Source
AI summary
A process for cooling or heating a fluid or a body by means of a vapor compression circuit including a centrifugal compressor and containing a heat-transfer fluid, the heat-transfer fluid including at least two compounds selected from 2,3,3,3-tetrafluoropropene, 1,3,3,3-tetrafluoropropene, 1,1,1,2-tetrafluoropropene, 1,1-difluoroethane and 3,3,3-trifluoropropene, in which: the ratio of the Mach number of the centrifugal compressor to the Mach number which the centrifugal compressor has under the same operating conditions if the heat-transfer fluid is replaced with 1,1,1,2-tetrafluoroethane in the vapor compression circuit is greater than or equal to 0.97 and less than or equal to 1.03; the compression ratio of the centrifugal compressor is less than or equal to the compression ratio which the centrifugal compressor has under the same operating conditions if the heat-transfer fluid is replaced with 1,1,12-tetrafluorethane in the vapor compression circuit.