Flooded Evaporator Phase Separation for Uniform Refrigerant Flow
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Solution Overview
Problem
Flooded evaporators face inefficiencies due to the challenge of uniformly distributing two-phase refrigerant and the vapor phase blocking the liquid refrigerant from contacting heat exchanger tubes, leading to reduced cooling efficiency.
Innovation Solution
The introduction of a partitioning wall within the evaporator shell to separate refrigerant into vapor and liquid phases, with specific outlets for each phase to ensure efficient distribution, where vapor refrigerant is supplied above the heat exchanger tubes and liquid refrigerant is supplied below, utilizing elongated apertures for efficient flow and minimizing pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two-phase refrigerant is supplied to the bottom of the shell in conventional flooded evaporators, then the refrigerant can be supplied to the evaporator, but the vapor phase blocks the liquid refrigerant from contacting the heat exchanger tubes, reducing cooling efficiency
Solution Approach 1:
The evaporator shell is divided into two separate chambers by a partitioning wall: a refrigerant receiving chamber for receiving two-phase refrigerant and an evaporator chamber for heat exchange. This segmentation allows the refrigerant to be separated into liquid and vapor phases in the receiving chamber before entering the evaporator chamber, preventing vapor from blocking liquid refrigerant contact with heat exchanger tubes.
Solution Approach 2:
The partitioning wall acts as an intermediary structure between the refrigerant receiving chamber and the evaporator chamber. It includes apertures that allow controlled passage of separated liquid refrigerant into the evaporator chamber while blocking vapor phase, thus mediating the refrigerant flow to eliminate the blocking effect.
2Ease of operation
If two-phase refrigerant is supplied to the evaporator, then refrigerant supply is simplified, but uniform distribution of liquid refrigerant to heat exchanger tubes becomes difficult
Solution Approach 1:
By segmenting the evaporator into a refrigerant receiving chamber and an evaporator chamber with a partitioning wall, the system simplifies refrigerant supply (two-phase refrigerant can be directly supplied to the receiving chamber) while simultaneously achieving uniform distribution through the separated liquid phase that passes through controlled apertures in the partitioning wall.
Solution Approach 2:
The partitioning wall incorporates apertures with specific dimensions and configurations that control the flow parameters of liquid refrigerant. By carefully designing the aperture size, shape, and distribution, the system transforms the two-phase refrigerant supply into uniform liquid distribution across the heat exchanger tubes.
3Productivity
If a partitioning wall with apertures is introduced to separate refrigerant phases, then refrigerant distribution efficiency is improved, but device complexity increases
Solution Approach 1:
The partitioning wall with apertures combines multiple functions into a single structure: it separates the refrigerant receiving chamber from the evaporator chamber, acts as a phase separator, and serves as a distribution manifold. This merging of functions improves refrigerant distribution efficiency while minimizing the increase in device complexity compared to using separate components for each function.
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
This configuration enhances the efficiency of the evaporator by ensuring homogeneous liquid refrigerant flow and preventing vapor obstruction, resulting in improved heat exchange and reduced complexity and cost compared to external separators.
Implementation Method 1
a refrigerant separator comprising said refrigerant receiving chamber and configured to separate the two-phase refrigerant into refrigerant vapour and liquid refrigerant
Implementation Method 2
one or more heat exchanger tubes passing therethrough for transmitting a fluid to be cooled through the evaporator chamber
Implementation Method 3
The heat from the heat exchanger tubes vaporises the refrigerant, which removes heat from the tubes and hence cools the fluid passing therethrough
Implementation Method 4
The heat from the heat exchanger tubes vaporises the refrigerant, which removes heat from the tubes and hence cools the fluid passing therethrough
Implementation Method 5
The heat from the heat exchanger tubes vaporises the refrigerant, which removes heat from the tubes
Data Source
AI summary
An evaporator system includes an evaporator chamber 28 having one or more heat exchanger tubes 4 passing therethrough for transmitting a fluid to be cooled through the evaporator chamber 28; and a refrigerant separator configured to separate a two-phase refrigerant into refrigerant vapour and liquid refrigerant, and having a first outlet 32 for the separated vapour refrigerant and a second outlet 30 for the separated liquid refrigerant; the first outlet 32 is arranged for supplying the vapour refrigerant into the evaporator chamber 28 at a location above at least some of the heat exchanger tubes 4, and the second outlet 30 is arranged for supplying the liquid refrigerant into the evaporator chamber 28 at a location below at least some of the heat exchanger tubes 4.