Flooded Evaporator Layout for Uniform Liquid Refrigerant Contact
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Solution Overview
Problem
Flooded evaporators face challenges in uniformly distributing liquid refrigerant and efficiency due to vapor refrigerant blocking liquid contact with heat exchanger tubes, leading to reduced performance.
Innovation Solution
An evaporator system with a partitioning wall dividing the shell into an evaporator chamber and a refrigerant receiving chamber, featuring a refrigerant separator that separates two-phase refrigerant into vapor and liquid phases, with specific outlets for each phase to ensure efficient distribution and contact with heat exchanger tubes, utilizing elongated apertures for low pressure drop and efficient liquid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two-phase refrigerant is supplied to the bottom of the shell in conventional flooded evaporators, then the evaporator structure is simple, but the vapor phase blocks liquid refrigerant from contacting heat exchanger tubes, reducing efficiency
Solution Approach 1:
The evaporator is segmented into two distinct chambers: a refrigerant receiving chamber for receiving two-phase refrigerant and an evaporator chamber for heat exchange. A partitioning wall separates these chambers, allowing independent optimization of each zone's function while maintaining overall system efficiency.
Solution Approach 2:
A refrigerant separator acts as an intermediary device between the refrigerant receiving chamber and the evaporator chamber. It separates the two-phase refrigerant into liquid and vapor phases, directing liquid refrigerant to the evaporator chamber while allowing vapor to be discharged, thereby preventing vapor from blocking liquid refrigerant contact with heat exchanger tubes.
2Productivity
If liquid refrigerant is sprayed uniformly down over heat exchanger tubes in falling film evaporators, then heat exchange efficiency is improved, but the system requires complex refrigerant distribution mechanisms
Solution Approach 1:
Instead of spraying liquid refrigerant downward over the tubes as in falling film evaporators, this invention allows liquid refrigerant to rise upward from below the heat exchanger tubes through elongated apertures in the partitioning wall. This inverted approach achieves uniform distribution without requiring complex spray mechanisms at the top.
Solution Approach 2:
The elongated apertures in the partitioning wall enable liquid refrigerant to automatically rise and distribute itself uniformly across the heat exchanger tubes through capillary action and pressure differential, without requiring external pumps or complex distribution nozzles. The system uses its own operating conditions to achieve uniform refrigerant distribution.
3Adaptability or versatility
If refrigerant vapor is present in the refrigerant supplied to the shell, then the evaporator can operate with two-phase refrigerant, but the vapor blocks liquid refrigerant contact with tubes, lowering efficiency
Solution Approach 1:
The refrigerant separator extracts the vapor phase from the two-phase refrigerant supply and directs it to a vapor discharge line, removing the harmful blocking effect. Only the liquid phase is allowed to pass into the evaporator chamber, ensuring efficient heat exchange while maintaining the ability to operate with two-phase refrigerant supply.
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
Enhances the efficiency of the evaporator by ensuring homogeneous liquid refrigerant flow and minimizing pressure drop, preventing vapor refrigerant from obstructing liquid contact, thus improving heat exchange and reducing system complexity and cost.
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
Data Source
Figure 1A~2
Figure 3A~3D
AI summary
An evaporator system is disclose comprising: 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; wherein 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 tubes4.