Mulitlevel distribution system for evaporator
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Solution Overview
Problem
Conventional falling film evaporators in HVAC&R systems require significant refrigerant volumes and complex piping for vapor-liquid separation, leading to large heat exchanger vessels and potential maldistribution issues.
Innovation Solution
A falling film evaporator design featuring a manifold with spray openings angled between 15 to 60 degrees below horizontal, a baffle acting as a porous momentum barrier, and a vapor sheath to manage refrigerant flow, reducing refrigerant charge and vessel size while maintaining uniform liquid distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a falling film evaporator uses conventional vapor-liquid separation and distribution piping, then reliable refrigerant distribution is achieved, but system complexity and refrigerant volume increase
Solution Approach 1:
The patent combines the vapor-liquid separation function and liquid distribution function into a single integrated manifold component. The manifold includes both vapor outlet ports and liquid distribution outlets, eliminating the need for separate separation vessels and distribution piping. This integration maintains reliable refrigerant distribution while significantly reducing system complexity and refrigerant charge volume.
Solution Approach 2:
The manifold is designed as a multi-functional component that simultaneously performs vapor-liquid separation, vapor discharge, and liquid distribution functions. By making the manifold universal for multiple functions, the patent eliminates redundant components and reduces overall system complexity while maintaining the reliability of refrigerant distribution.
2Quantity of substance
If a falling film evaporator uses conventional distribution system, then adequate liquid refrigerant supply is ensured, but heat exchanger vessel size increases
Solution Approach 1:
The integration of separation and distribution functions into the manifold eliminates the need for large separate distribution vessels. The manifold's internal geometry provides sufficient liquid holdup and distribution capability without requiring additional vessel volume, thus ensuring adequate liquid refrigerant supply while minimizing heat exchanger vessel size.
Solution Approach 2:
The patent utilizes the vertical dimension within the manifold structure to create effective vapor-liquid separation and liquid distribution. By designing the manifold with vertical vapor outlets and downward-oriented liquid distribution outlets, the system achieves adequate liquid supply functionality within a compact volume by exploiting spatial arrangement in multiple dimensions.
3Device complexity
If spray openings are oriented horizontally, then refrigerant distribution is simplified, but liquid refrigerant distribution uniformity decreases
Solution Approach 1:
The patent employs asymmetric orientation of spray openings relative to the manifold axis. The spray openings are angled downward at specific angles (e.g., 30-60 degrees from horizontal) rather than being purely horizontal. This asymmetric configuration uses gravity to improve liquid distribution uniformity across the evaporator tubes while maintaining relatively simple system design.
Solution Approach 2:
The spray openings are strategically positioned and angled to target specific regions of the evaporator tube bundle. By varying the orientation and position of different spray openings locally, the system achieves uniform liquid distribution across all tubes despite the overall simplicity of the distribution system design.
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 design enhances refrigerant distribution, reduces system complexity and cost, and improves thermal energy exchange efficiency by minimizing refrigerant volume and preventing dry spots on evaporator tubes.
Implementation Method 1
The baffle comprises a porous momentum barrier
Implementation Method 2
The vapor and liquid refrigerant mixture is impinged on a baffle located between the manifold and the distribution vessel and the liquid refrigerant is separated from the vapor and liquid refrigerant mixture via the impingement
Implementation Method 3
Refrigerant liquid flows in the direction of gravity, falls on the evaporator tubes
Implementation Method 4
spraying the two-phase vapor and liquid refrigerant mixture out of the manifold through a plurality of manifold openings
Implementation Method 5
conveying a two-phase vapor and liquid refrigerant mixture to a manifold and spraying the two-phase vapor and liquid refrigerant mixture
Implementation Method 6
Different methods have been implemented to distribute liquid on the falling film tubes using single-phase gravity feed
Implementation Method 7
Evaporation is accomplished through thin film evaporation on the surface of the evaporator tubes
Implementation Method 8
use an evaporator to facilitate a thermal energy exchange between a refrigerant in the evaporator and a medium flowing in a number of evaporator tubes
Data Source
AI summary
A falling film evaporator includes a housing and a plurality of evaporator tubes located in the housing. A liquid refrigerant distribution system is positioned in the housing and includes a manifold having a plurality of manifold outlet openings and a baffle positioned between the manifold and a distribution vessel and comprising a plurality of baffle openings. The distribution vessel has a plurality of distribution vessel openings for conveying the liquid refrigerant onto evaporator tubes when in use. A method of operating an evaporator includes conveying a two-phase vapor and liquid refrigerant mixture to a manifold and spraying the mixture out of the manifold through a plurality of manifold openings toward a distribution vessel. The mixture in impinged on a baffle located between the manifold and the distribution vessel and the liquid refrigerant is separated from the mixture via the impingement. The liquid refrigerant is collected at the distribution vessel.