U-Shaped Liquid Separator for Compact Plate Heat Exchangers
Solution Overview
Problem
Traditional plate heat exchanger evaporators and liquid separators are bulky, costly, and inefficient, with high refrigerant content posing safety risks and requiring extensive space and support, while existing separators are heavy and difficult to integrate with evaporators due to their size and weight.
Innovation Solution
A U-shaped pipe design for the liquid separator with two parallel pipes interconnected by a pipe portion, arranged horizontally to enhance compactness and separation efficiency, reducing weight and refrigerant charge, and allowing for the use of standard pipe components and higher-grade materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional liquid separator is used, then separation function is provided, but weight and space requirements increase significantly
Solution Approach 1:
The separator is segmented into multiple vertical channels formed by alternating sealing means between heat transfer plates, distributing the separation function across multiple parallel pathways rather than requiring a single large separator volume
Solution Approach 2:
The separator function is merged with the plate heat exchanger structure itself, where the plate pack and sealing means perform both heat exchange and liquid-vapor separation functions simultaneously, eliminating the need for a separate standalone separator
2Reliability
If a traditional liquid separator is used, then separation function is provided, but device complexity and integration difficulty increase
Solution Approach 1:
The separator is integrated into the plate heat exchanger assembly, where the same plate pack structure that performs heat exchange also provides the separation function through alternating sealing patterns, reducing the number of separate components and simplifying integration
Solution Approach 2:
The heat transfer plates and sealing means serve dual functions: heat exchange between refrigerant streams and liquid-vapor separation, making the system more versatile and reducing overall device complexity
3Reliability
If higher refrigerant content is used in separator, then separation efficiency is improved, but safety risks increase
Solution Approach 1:
The refrigerant volume is segmented across multiple small vertical channels rather than concentrated in a large separator, maintaining adequate separation efficiency while limiting the total refrigerant charge to a safer level
Solution Approach 2:
The separator transitions from a horizontal configuration to vertical channels, utilizing the vertical dimension for liquid settling while reducing the horizontal footprint and overall refrigerant volume required
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 compact design improves separation efficiency, reduces weight and space requirements, lowers costs, and enhances safety by minimizing refrigerant content, while allowing for efficient operation at part loads with reduced pressure drop and adapted driving liquid levels.
Implementation Method 1
The separation of the vapour and the liquid is obtained by gravitational forces, sometimes assisted by centrifugal forces, which allow the heavier liquid droplets to settle.
Implementation Method 2
The plates are in contact with one fluid through one of their side surfaces and with the other fluid through the other side surface, which allows a considerable heat exchange between the two fluids.
Implementation Method 3
Before the refrigerant enters the evaporator the pressure of the refrigerant has to be brought down to the evaporating pressure and temperature by expanding the refrigerant. In this process a part of the refrigerant vaporises. The energy released by the cooling/expansion is absorbed by the evaporating refrigerant.
Data Source
Figure 1~3
Figure 4~6
AI summary
Liquid separator (2), designed as a U-shaped pipe (5) and arranged essentially horizontally, for a plate heat exchanger evaporator (1) system for separation of liquid droplets from vapour transported from the evaporator to the separator.