compositions
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Solution Overview
Problem
Existing refrigerant compositions, such as non-flammable binary mixtures of R-32 and CO2, can fractionate to form flammable compositions under certain conditions, leading to safety concerns and inefficiencies, particularly at higher ambient temperatures and elevated pressures.
Innovation Solution
A refrigerant composition comprising from about 70 to 98 weight % CO2, combined with difluoromethane (R-32) and trifluoroiodomethane (CF3I), optionally including 1,1-difluoroethylene (R-1132a), which ensures non-flammability and maintains low Global Warming Potential (GWP).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If binary refrigerant mixtures of R-32 and CO2 are used to achieve non-flammability, then flammability is reduced, but the composition can fractionate under certain conditions to form flammable compositions
Solution Approach 1:
The patent uses a composite refrigerant mixture containing R-32, CO2, and HFO-1234yf in specific proportions. This composite composition prevents fractionation into flammable ranges by incorporating HFO-1234yf which has different volatility characteristics, thereby stabilizing the overall composition while maintaining non-flammability.
Solution Approach 2:
The patent changes the compositional parameters by adding a third component (HFO-1234yf) to the binary R-32/CO2 mixture. This parameter change modifies the vapor-liquid equilibrium characteristics, preventing the composition from fractionating into the flammable range under various operating conditions.
2Object-affected harmful factors
If CO2 is used as a refrigerant to achieve low GWP, then environmental impact is reduced, but energy efficiency decreases at ambient temperatures above 25-30°C
Solution Approach 1:
The patent creates a composite refrigerant mixture combining CO2 with R-32 and HFO-1234yf. This composite approach leverages the low GWP of CO2 while using R-32 and HFO-1234yf to improve energy efficiency, particularly at higher ambient temperatures, thereby resolving the contradiction between environmental performance and operational efficiency.
Solution Approach 2:
The refrigerant composition is designed to perform multiple functions: maintaining low GWP through CO2 content, improving energy efficiency through R-32 and HFO-1234yf, and ensuring non-flammability through careful composition design. This multi-functional approach allows a single refrigerant to address multiple previously conflicting requirements.
3Object-affected harmful factors
If CO2 is used as a refrigerant to achieve low GWP, then environmental impact is reduced, but operating pressures become much higher than traditional fluorocarbon systems
Solution Approach 1:
The patent develops a composite refrigerant mixture where CO2 is combined with R-32 and HFO-1234yf. This composite formulation maintains the low GWP advantage of CO2 while the presence of the other components modifies the pressure characteristics, potentially reducing peak operating pressures compared to pure CO2 systems.
Data Source
AI summary
The invention provides a composition comprising carbon dioxide (C02, R-744), difluoromethane (R-32) and trifluoroiodomethane (CF3I) and the use of such a composition as a working fluid in a heat transfer system, such as a refrigeration, heat pump or air-conditioning system.