Carbon dioxide refrigerant system
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Solution Overview
Problem
Carbon dioxide refrigerant systems using co-fluids face inefficiencies due to faster absorption rates than desorption rates, leading to potential system inoperability and pressure issues, necessitating a co-fluid that balances absorption and desorption rates for stable operation.
Innovation Solution
The use of tertiary amines as co-fluids, which absorb and desorb carbon dioxide at similar rates, mitigating the formation of carbamic acid compounds and ensuring efficient operation by maintaining balanced absorption and desorption processes, thereby stabilizing the system's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If carbon dioxide is used as refrigerant with co-fluid, then environmental friendliness is improved, but pressure becomes too high for conventional systems
Solution Approach 1:
The patent changes the chemical composition parameter of the refrigerant system by introducing tertiary amine co-fluids with specific molecular structures. This alters the thermodynamic properties of the system, enabling CO2 to be used at lower pressures while maintaining refrigeration effectiveness. The tertiary amine's chemical properties facilitate CO2 absorption and desorption at manageable pressure levels.
2Stress or pressure
If carbon dioxide is absorbed into co-fluid, then pressure is lowered during compression, but desorption rate becomes slower than absorption rate
Solution Approach 1:
The patent modifies the chemical parameters of the co-fluid by selecting tertiary amines with specific structural characteristics (at least two alkyl groups on the nitrogen atom). This chemical parameter change fundamentally alters the absorption-desorption kinetics, achieving near-equal rates for both processes. The specific molecular structure enables faster desorption compared to primary or secondary amines.
Solution Approach 2:
The patent creates a composite refrigerant system combining carbon dioxide with tertiary amine co-fluids. This composite material approach leverages the complementary properties of CO2 (environmental friendliness, high heat transfer coefficient) and tertiary amines (moderate desorption rate, chemical stability) to achieve balanced absorption-desorption performance.
3Quantity of substance
If carbon dioxide accumulates in co-fluid due to rate difference, then system efficiency decreases, but system becomes inoperable
Solution Approach 1:
The patent establishes a feedback mechanism through the reversible absorption-desorption equilibrium. The tertiary amine co-fluid automatically adjusts CO2 uptake and release based on system conditions (temperature, pressure), preventing accumulation when desorption is slow and ensuring adequate CO2 availability when needed. This self-regulating behavior maintains system reliability.
Solution Approach 2:
The patent changes the kinetic parameters of the CO2-co-fluid interaction by using tertiary amines. This parameter change ensures that the desorption rate matches the absorption rate, preventing CO2 accumulation and maintaining continuous, reliable system operation. The specific chemical parameters of tertiary amines create optimal mass transfer kinetics.
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
Tertiary amines facilitate equal absorption and desorption rates, enhancing the operational efficiency and continuous cooling or refrigeration capabilities of HVAC&R systems, reducing the risk of system failure and pressure issues.
Implementation Method 1
carbon dioxide refrigerant is absorbed into and desorbed out of the co-fluid
Implementation Method 2
mitigating the formation of carbamic acid compounds
Implementation Method 3
carbon dioxide refrigerant is absorbed into and desorbed out of the co-fluid
Implementation Method 4
Subsequent flow through an expansion device and evaporator requires a desirable release (desorption) of a portion of the carbon dioxide refrigerant
Data Source
AI summary
A compressor including a refrigerant and a lubricant, wherein the lubricant comprises at least one compound selected from the group consisting of a mono-tertiary amine, a di-tertiary amine, a tri-tertiary amine, and a tetra-tertiary amine.