Organic Rankine Cycle Working Fluid Composition for Low GWP Heat Recovery
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Solution Overview
Problem
Current organic rankine cycle technologies face challenges with high global warming potential, environmental impact, and inefficient heat transfer performance using existing working fluids, particularly at low temperatures, necessitating a more environmentally friendly and efficient solution for converting thermal energy into mechanical energy.
Innovation Solution
A method utilizing a working fluid composition predominantly composed of cis-1,3,3,3-tetrafluoropropene and 1,1,1,3,3-pentafluoropropane, with a mass ratio of 90.0-99.9% and 0.1-10.0% respectively, which is non-flammable or low flammable, has a low global warming potential, and enhances heat transfer and thermal energy conversion characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional working fluids (water, traditional organic compounds) are used in organic rankine cycle, then the system can convert thermal energy to mechanical energy, but the global warming potential is high and environmental impact is severe
Solution Approach 1:
The patent changes the chemical composition parameters of the working fluid by using cis-1,3,3,3-tetrafluoropropene (90.0-99.9% by mass) and 1,1,1,3,3-pentafluoropropene (0.1-10.0% by mass) instead of conventional working fluids. This parameter change achieves low global warming potential (GWP less than 150) while maintaining adequate thermal energy conversion efficiency through optimized compositional ratios
Solution Approach 2:
The patent employs a composite working fluid system combining two different fluorocarbon compounds (cis-1,3,3,3-tetrafluoropropene and 1,1,1,3,3-pentafluoropropene) in specific proportions. This composite approach leverages the complementary properties of each component to achieve both environmental compatibility and thermodynamic performance
2Temperature
If existing working fluids are used, then the organic rankine cycle can operate, but the heat transfer performance is insufficient particularly at low temperatures
Solution Approach 1:
The patent optimizes the thermal properties of the working fluid by selecting specific fluorocarbon compounds with appropriate boiling points and heat capacity characteristics. The chosen composition (cis-1,3,3,3-tetrafluoropropene and 1,1,1,3,3-pentafluoropropene) exhibits improved heat transfer coefficients at low temperatures while maintaining the temperature range suitability for waste heat recovery applications
Solution Approach 2:
The patent tailors the working fluid properties to match the specific thermal conditions of low-temperature heat sources. The selected fluorocarbon mixture provides optimized heat transfer characteristics in the low-temperature regime (typically 50-150°C), addressing the local thermal performance requirement rather than追求 universal performance across all temperature ranges
3Object-affected harmful factors
If working fluids with low global warming potential are selected, then environmental impact is reduced, but the thermal energy conversion efficiency decreases
Solution Approach 1:
The patent achieves a balance between environmental impact and energy efficiency by precisely controlling the compositional parameters of the working fluid. The specific mass ratio range (cis-1,3,3,3-tetrafluoropropene: 90.0-99.9%, 1,1,1,3,3-pentafluoropropene: 0.1-10.0%) is optimized to maintain adequate thermal energy conversion efficiency while ensuring low global warming potential (GWP less than 150)
Solution Approach 2:
The patent creates a composite working fluid that combines the environmental benefits of low-GWP fluorocarbons with improved thermodynamic performance. The synergistic interaction between cis-1,3,3,3-tetrafluoropropene and 1,1,1,3,3-pentafluoropropene in the specified composition range achieves both environmental compatibility and acceptable energy conversion efficiency
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 method achieves high heat transfer characteristics and thermal energy conversion efficiency while reducing environmental impact, making it suitable for converting middle-to-low-temperature thermal energy into mechanical energy, thereby improving the performance and sustainability of organic rankine cycle systems.
Implementation Method 1
The working medium performs heat exchange with an external heat source in the step of isobaric heating
Implementation Method 2
an evaporator that evaporates the working medium
Implementation Method 3
The working medium is subjected to adiabatic expansion to provide energy (work) to the outside
Implementation Method 4
a condenser... isobaric cooling (condensation)
Data Source
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AI summary
Provided is a method for converting thermal energy into mechanical energy by use of an organic rankine cycle system that accommodates a working fluid composition. The method includes sequentially performing: evaporating the working fluid composition; expanding the working fluid composition; condensing the working fluid composition; and transferring the working fluid composition, while raising a pressure thereof, by a pump. The working fluid composition contains cis-1,3,3,3-tetrafluoropropene at a ratio higher than or equal to 92.0% by mass and lower than or equal to 99.9% by mass and trans-1,3,3,3-tetrafluoropropene or 2,3,3,3-tetrafluoropropene at a ratio higher than or equal to 0.1% by mass and lower than or equal to 8.0% by mass; and has an evaporation temperature higher than or equal to 60°C and lower than or equal to 150°C.