Plate Heat Exchanger With Integrated Suction Gas Sections
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Solution Overview
Problem
Current refrigeration systems face inefficiencies due to high refrigerant volume requirements, material costs, and the need for large, bulky heat exchangers, particularly in achieving zero superheat for compressors and minimizing flash boiling, while also dealing with co-current heat exchange inefficiencies and refrigerant droplet issues.
Innovation Solution
A brazed plate heat exchanger with alternating interplate flow channel volumes and chevron angles, integrated suction gas heat exchangers, and a balance valve system to control heat exchange, ensuring minimal superheat and efficient fluid distribution, thereby reducing pressure drop and enhancing heat transfer performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flooded evaporator configuration is used to achieve zero superheat, then heat exchange efficiency is improved, but refrigerant volume requirement increases significantly
Solution Approach 1:
The heat exchanger is divided into multiple plate packs with different interplate flow channel volumes. Some plate packs have larger volumes to facilitate flooding and zero superheat, while others have smaller volumes to reduce overall refrigerant charge. This segmentation allows different regions to serve different functional purposes within the same heat exchanger unit.
Solution Approach 2:
Different sections of the heat exchanger are designed with locally optimized properties. The suction gas heat exchanger section has larger interplate flow channel volumes to enable liquid refrigerant accumulation and flash gas generation, while other sections have smaller volumes. This local differentiation allows the system to achieve zero superheat without requiring the entire heat exchanger to have large volume.
2Productivity
If plate and shell or shell and tube heat exchangers are used for flooded evaporator applications, then heat exchange performance is improved, but device weight and material cost increase
Solution Approach 1:
The invention merges the functions of the flooded evaporator and the suction gas heat exchanger into a single integrated plate heat exchanger unit. The plate pack structure serves both purposes simultaneously, eliminating the need for separate shell and tube heat exchangers and reducing overall system weight and material cost.
Solution Approach 2:
The plate heat exchanger is designed as a multi-functional device that can operate as both a flooded evaporator and a suction gas heat exchanger. By configuring certain plate packs with larger interplate flow channel volumes, the same structure achieves multiple functions that traditionally required separate dedicated heat exchangers.
3Productivity
If alternating interplate flow channel volumes are used to enable liquid refrigerant distribution, then heat exchange efficiency is improved, but pressure drop increases
Solution Approach 1:
The system dynamically adapts refrigerant flow distribution based on local conditions. The alternating pattern of large and small interplate flow channel volumes creates dynamic flow behavior where liquid refrigerant is directed to large volume sections for flash gas generation, while small volume sections maintain higher velocity for efficient heat exchange. This dynamic adaptation optimizes both efficiency and pressure drop characteristics.
Solution Approach 2:
The interplate flow channel volume parameter is varied spatially throughout the heat exchanger. By changing this geometric parameter from section to section, the system optimizes local flow characteristics. Large volumes in suction gas heat exchanger sections facilitate liquid accumulation, while smaller volumes in evaporator sections enhance heat exchange efficiency, creating an overall optimized pressure drop profile.
4Device complexity
If co-current heat exchange is used in evaporator, then system simplicity is maintained, but heat exchange efficiency decreases
Solution Approach 1:
The invention inverts the traditional approach by using the temperature difference between warm liquid refrigerant and cold flash gas in reverse. Instead of treating the warm liquid as a heat source to be cooled, the system uses it to heat and vaporize the cold liquid refrigerant in the suction gas heat exchanger section. This inverted heat exchange approach improves efficiency while maintaining co-current flow simplicity.
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 achieves close to zero superheat for refrigerant entering the compressor, reduces refrigerant volume needs, and improves heat exchanger performance by balancing fluid flow and pressure drop, allowing for efficient operation in both heating and chilling modes with reduced energy consumption.
Implementation Method 1
a plurality of heat exchanger plates provided with a pressed pattern adapted to provide contact points keeping the heat exchanger plates on a distance from one another such that interplate flow channels are formed between said plates, said heat exchanger being provided with interplate flow channels for a first medium exchanging heat with a second medium
Implementation Method 2
first and second integrated suction gas heat exchanger sections are provided in the vicinity of port openings for the second medium and third medium
Implementation Method 3
exchanging heat between high temperature liquid refrigerant from the condenser and low temperature gaseous refrigerant from the evaporator
Data Source
AI summary
A plate heat exchanger (500) includes a plurality of heat exchanger plates (510, 520, 530, 540) provided with a pressed pattern adapted to provide contact points keeping the heat exchanger plates on a distance from one another such that interplate flow channels are formed between said plates, said heat exchanger being provided with interplate flow 5 channels (510-520, 530-540) for a first medium exchanging heat with a second medium in interplate flow channels (520-530) and a third medium in interplate flow channels (540-510), wherein the interplate flow channels are in selective fluid communication with port openings (550, 560, 570, 580, 630, 620) for the first medium, the second medium and the third medium. The heat exchanger (500) comprises first and second integrated suction gas heat exchanger sections (ISGHX1, ISGHX2) provided in the vicinity of port openings (550, 560, 570, 580) for the second medium and third medium. Every other heat exchanger plate is formed with a pressed first pattern of ridges and grooves, and the other heat exchanger plates are formed with a pressed second pattern of ridges and grooves, wherein the first pattern of ridges and grooves is different from 15 the second pattern of ridges and grooves.