Evaporator Gas Trap Distributor for Low Refrigerant Charge
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Solution Overview
Problem
Existing refrigerant systems require excessive liquid refrigerant to effectively wet the entire tube bundle in evaporators, leading to inefficiencies and increased refrigerant charge, as previous solutions either add complexity or fail to adequately displace liquid refrigerant from ineffective areas.
Innovation Solution
A distributor system that utilizes the gaseous portion of a two-phase refrigerant mixture to displace liquid refrigerant in ineffective areas, creating gas trap chambers and evenly distributing liquid refrigerant across the tube bundle, minimizing the overall refrigerant charge by trapping pockets of gaseous refrigerant and using it to displace liquid, thereby reducing the amount needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a distributor is designed to wet the entire tube bundle with liquid refrigerant, then heat transfer efficiency is improved, but the amount of liquid refrigerant required increases
Solution Approach 1:
The patent utilizes the phase transition between liquid and gaseous refrigerant. Gas trap chambers are positioned to intercept gaseous refrigerant rising from the tube bundle, preventing it from mixing with liquid refrigerant in the distributor. This phase separation allows the distributor to use less liquid refrigerant while maintaining effective wetting of the tube bundle, as the gaseous refrigerant contributes to the wetting process without requiring additional liquid charge.
Solution Approach 2:
The distributor is segmented into multiple gas trap chambers positioned at different locations within the distributor structure. Each chamber captures gaseous refrigerant in a specific zone, creating multiple separation points that collectively reduce the overall liquid refrigerant requirement while ensuring comprehensive coverage of the tube bundle surface.
2Device complexity
If liquid refrigerant is allowed to collect below the tube bundle, then the distributor structure is simplified, but heat transfer effectiveness is reduced due to liquid refrigerant in ineffective areas
Solution Approach 1:
Gas trap chambers are positioned to intercept gaseous refrigerant before it can mix with and allow liquid refrigerant to accumulate in ineffective areas below the tube bundle. The chambers create a phase separation barrier that prevents liquid refrigerant from entering regions where it cannot participate in heat transfer, thereby maintaining heat transfer effectiveness without requiring complex additional drainage structures.
3Ease of operation
If gaseous refrigerant is allowed to mix with liquid refrigerant in the distributor, then the system operation is simplified, but the amount of liquid refrigerant required increases due to displacement effects
Solution Approach 1:
The gas trap chambers are strategically positioned within the distributor to intercept gaseous refrigerant as it rises, preventing mixing with liquid refrigerant. This phase separation maintains simple system operation by allowing natural phase separation to occur within the distributor structure itself, while simultaneously reducing the liquid refrigerant charge required by preventing gaseous refrigerant from displacing liquid in the distribution channels.
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 effectively reduces the refrigerant charge in the evaporator while ensuring even wetting of the tube bundle, enhancing heat transfer efficiency and minimizing unnecessary refrigerant usage.
Implementation Method 1
uses the gaseous portion of a two-phase refrigerant mixture to displace liquid refrigerant in ineffective areas
Implementation Method 2
creating gas trap chambers and evenly distributing liquid refrigerant across the tube bundle, minimizing the overall refrigerant charge by trapping pockets of gaseous refrigerant
Implementation Method 3
evenly distributing liquid refrigerant across the tube bundle
Implementation Method 4
Heat exchange contact between the relatively cool refrigerant and the relatively warm heat transfer medium flowing through the tube bundle causes the refrigerant to vaporize and the heat transfer medium to be cooled
Implementation Method 5
causes the refrigerant to vaporize
Implementation Method 6
the refrigerant delivered from the expansion device to the evaporator is a relatively cool, saturated two-phase mixture
Data Source
AI summary
A shell-and-tube evaporator of a refrigerant system includes a refrigerant inlet distributor that traps a pocket of gaseous refrigerant to displace liquid refrigerant underneath the evaporator's tube bundle, thereby reducing the total charge of refrigerant in the evaporator. In some embodiments, the distributor comprises four sections interconnected by a central refrigerant feed line, which properly apportions the refrigerant to the four sections.