Refrigerant Accumulator Atomization for Cooler Vapor Compression
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Solution Overview
Problem
Vapor compression systems face challenges with new low global warming potential refrigerants, including higher discharge temperatures, increased glide, lower density, and reduced evaporator performance, which affect efficiency and environmental impact, and the compression process is adiabatic, limiting efficiency compared to isothermal compression.
Innovation Solution
Incorporating an accumulator that atomizes the liquid phase of the working fluid into droplets and introduces them into the vapor phase, allowing for improved heat transfer and isothermal compression, reducing temperature superheat and increasing efficiency, while also reducing the complexity and footprint of the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If new low GWP refrigerants are used, then environmental impact is reduced, but discharge temperature increases and evaporator performance decreases
Solution Approach 1:
The accumulator performs preliminary action by atomizing liquid refrigerant into fine droplets and introducing them into the vapor phase before compression. This pre-cools the vapor and prepares it for more efficient compression, addressing the high discharge temperature issue of low GWP refrigerants before they enter the compressor
Solution Approach 2:
The invention utilizes phase transition by introducing liquid phase refrigerant droplets into the vapor phase stream. The liquid droplets evaporate during compression, absorbing heat and enabling more efficient heat transfer. This phase change mechanism directly addresses the thermal management challenges of low GWP refrigerants
2Speed
If adiabatic compression is used, then compression speed is maintained, but compression efficiency is limited compared to isothermal compression
Solution Approach 1:
The accumulator introduces liquid refrigerant that evaporates during compression, utilizing the phase transition from liquid to vapor. This evaporation process absorbs compression heat, enabling more efficient heat transfer during the compression process and improving overall compression efficiency while maintaining compression speed
Solution Approach 2:
The system changes the thermal parameters during compression by introducing liquid droplets that evaporate and absorb heat. This dynamic parameter change allows the compression process to approach isothermal conditions more closely, improving efficiency without sacrificing compression speed
3Object-affected harmful factors
If low density refrigerants are used, then environmental impact is reduced, but evaporator performance and system capacity decrease
Solution Approach 1:
The accumulator performs preliminary action by atomizing liquid refrigerant into fine droplets and introducing them into the vapor phase before the evaporator. This increases the surface area of liquid refrigerant available for heat transfer, compensating for the lower density of low GWP refrigerants and maintaining evaporator performance
Solution Approach 2:
The invention changes the physical parameters of the refrigerant by creating a two-phase mixture with fine liquid droplets dispersed in vapor. This increases the effective heat transfer surface area and improves heat transfer coefficients, compensating for the lower density of low GWP refrigerants
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 solution enhances compression efficiency, reduces the risk of liquid slugging, and allows for the use of high glide refrigerant blends, improving overall system performance and environmental impact while maintaining cost-effectiveness.
Implementation Method 1
The accumulator is operable to atomize the liquid phase of the working fluid into droplets and introduce the droplets into the vapor phase of the working fluid exiting the accumulator
Implementation Method 2
allowing for improved heat transfer and isothermal compression, reducing temperature superheat and increasing efficiency
Data Source
AI summary
A vapor compression system includes a compressor including a compression stage for compressing a working fluid, a first heat exchanger downstream from the compressor that receives and cools the working fluid, a second heat exchanger downstream from the first heat exchanger and upstream from the compressor that receives and heats the working fluid, and an accumulator positioned between the second heat exchanger and the compression stage. The accumulator defines an interior volume for containing a vapor phase and a liquid phase of the working fluid, and the accumulator includes an inlet to receive the working fluid from the second heat exchanger and an outlet to allow the vapor phase of the working fluid to exit the accumulator and flow towards the compression stage. The accumulator atomizes the liquid phase of the working fluid into droplets and introduces the droplets into the vapor phase of the working fluid exiting the accumulator.