ORC Refrigerant Composition for Higher Condenser Pressure
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Solution Overview
Problem
Existing fluids used in organic Rankine cycle systems, such as polyfluorinated ethers and ketones, suffer from low pressure at the condenser, leading to air infiltration, corrosion, and mechanical damage due to moisture and oxygen presence, which is not effectively addressed by current alternatives like HFC-245fa.
Innovation Solution
The use of hydrofluoroolefins with specific alkyl groups substituted with fluorine and optionally chlorine atoms, which have negligible ozone depletion potential and global warming potential, as refrigerants in organic Rankine cycle systems, operating at low temperatures between 60 and 150°C, with critical temperatures above 150°C, and optionally combined with other compounds like hydrofluorocarbons, hydrocarbons, and ethers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyfluorinated ethers or ketones are used as refrigerants in organic Rankine cycle systems, then energy conversion is achieved, but low pressure at the condenser promotes air infiltration leading to corrosion and mechanical part destruction
Solution Approach 1:
The patent changes the chemical composition parameters of the refrigerant by using hydrofluoroolefins with specific molecular structures (at least 4 carbon atoms, specific fluorine substitution patterns) instead of polyfluorinated ethers or ketones. This parameter change results in higher condenser pressure while maintaining energy conversion efficiency, thereby preventing air infiltration and corrosion issues.
2Power
If existing refrigerants are used in organic Rankine cycle systems, then energy conversion operates, but greenhouse gas impact and ozone depletion potential are significant
Solution Approach 1:
The patent modifies the chemical composition parameters by selecting hydrofluoroolefins with specific molecular characteristics (formula R1CH=CHR2 with R1 and R2 being alkyl groups with 1-6 carbon atoms, substituted with fluorine and optionally chlorine atoms). These compositional changes achieve negligible ozone depletion potential and reduced global warming potential while maintaining effective energy conversion operation.
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
Hydrofluoroolefins provide a suitable fluid for energy conversion in organic Rankine cycle systems, reducing corrosion and air infiltration, while maintaining high efficiency and compatibility, with the ability to operate at higher temperatures and lower environmental impact compared to existing fluids.
Implementation Method 1
a step of evaporation of a refrigerant
Implementation Method 2
an expansion step in a turbine... turbines produce electricity by utilizing the phenomenon of expansion to drive a wheel
Implementation Method 3
a step of condensation of said fluid
Implementation Method 4
a step of desuperheating in an internal exchanger
Data Source
AI summary
The present invention relates to the use of a refrigerant in organic Rankine cycle systems comprising at least one hydrofluoroolefin, having at least four carbon atoms represented by the formula (I) R1CH═CHR2 in which R1 and R2 independently represent alkyl groups having from 1 to 6 carbon atoms, substituted with at least one fluorine atom, optionally with at least one chlorine atom.