Intermediate Heat Exchanger Layout for Sub-Cooled Fluoroolefin Cycles
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Solution Overview
Problem
Current vapor compression heat transfer systems, particularly those using fluoroolefins, face limitations in improving cooling capacity and energy efficiency, as existing methods do not effectively utilize the potential of sub-cooling to enhance refrigeration performance.
Innovation Solution
Incorporating an internal heat exchanger and utilizing fluoroolefins like 2,3,3,3-tetrafluoropropene (HFC-1234yf) within a vapor compression heat transfer system, which involves sub-cooling the working fluid by transferring heat between the liquid and gaseous phases through an intermediate heat exchanger, thereby increasing refrigeration capacity and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional vapor compression heat transfer systems use conventional working fluids and heat exchange methods, then the system structure is simple, but the cooling capacity and energy efficiency are limited
Solution Approach 1:
The heat exchanger is divided into multiple sections with different flow patterns (counter-current, cross-current, parallel-current) to optimize heat transfer in each section. This segmentation allows the system to achieve superior cooling capacity by utilizing sub-cooling effects while maintaining manageable structural complexity through modular design
Solution Approach 2:
An intermediate heat exchanger is introduced as a mediator between the condenser and evaporator to transfer heat from the high-pressure liquid refrigerant to the low-pressure suction gas. This intermediary component enables sub-cooling of the liquid refrigerant below its saturation temperature, thereby increasing cooling capacity without requiring complete system redesign
2Loss of energy
If sub-cooling is applied to the working fluid in vapor compression heat transfer systems, then energy efficiency improves by up to 7.67%, but the heat exchanger structure becomes more complex
Solution Approach 1:
The intermediate heat exchanger merges multiple heat transfer functions into a single integrated component: it sub-cools the high-pressure liquid refrigerant, pre-heats the low-pressure suction gas, and recovers heat from the refrigerant stream. This consolidation achieves energy efficiency improvements of up to 7.67% while avoiding the need for multiple separate heat exchange devices
Solution Approach 2:
The system changes the thermal parameters of the working fluid by sub-cooling the liquid refrigerant below its saturation temperature and superheating the suction gas above its saturation temperature. These parameter changes optimize the thermodynamic cycle efficiency, achieving up to 7.67% energy efficiency improvement through controlled temperature modifications in the intermediate heat exchanger
3Productivity
If fluoroolefins are used as working fluids with sub-cooling, then cooling capacity increases by up to 7.5%, but the system requires specialized heat exchange components
Solution Approach 1:
The heat exchanger design incorporates dynamic flow patterns that adapt to the thermodynamic properties of fluoroolefin working fluids. The counter-current, cross-current, and parallel-current sections create varying flow dynamics that optimize heat transfer coefficients for fluoroolefins, achieving up to 7.5% cooling capacity increase while using standard manufacturing techniques for each modular section
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 method significantly enhances cooling capacity and energy efficiency by up to 7.5% and 7.67% respectively, compared to traditional systems, demonstrating improved performance with fluoroolefins like HFC-1234yf when sub-cooling is applied.
Implementation Method 1
transferring heat between the liquid and gaseous phases through an intermediate heat exchanger
Implementation Method 2
sub-cooling the working fluid by transferring heat between the liquid and gaseous phases
Implementation Method 3
through the evaporator to evaporate the working fluid into a gas
Implementation Method 4
through the condenser to condense the compressed working fluid gas into a liquid
Data Source
AI summary
A multi-step method is disclosed for exchanging heat in a vapor compression heat transfer system having a working fluid circulating therethrough. The method includes the step of circulating a working fluid comprising a fluoroolefin to an inlet of a first tube of an internal heat exchanger, through the internal heat exchanger and to an outlet thereof. Also disclosed are vapor compression heat transfer systems for exchanging heat. The systems include an evaporator, a compressor, a dual-row condenser and an intermediate heat exchanger having a first tube and a second tube. A disclosed system involves a dual-row condenser connected to the first and second intermediate heat exchanger tubes. Another disclosed system involves a dual-row evaporator connected to the first and second intermediate heat exchanger tubes.