Multiple Flash Tank Refrigerant System to Reduce Weight and Cost

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Solution Overview

Problem

Current refrigerant vapor compression systems require bulky and costly flash tanks that are heavy, limiting configuration options and increasing manufacturing costs, especially for transcritical systems using carbon dioxide as a refrigerant.

Innovation Solution

A refrigerant vapor compression system utilizing multiple flash tanks with reduced operating pressures and volumes, coupled by connections that include separation devices such as baffles or screens, allowing for more compact and efficient configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single flash tank is used in the refrigerant system, then refrigerant separation function is provided, but the flash tank becomes bulky and adds weight to the vapor compression system

Engineering Contradiction:
Improverefrigerant separation functionVSAvoidsystem weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent divides a single large flash tank into multiple smaller flash tanks (first flash tank and second flash tank) that are coupled together. This segmentation maintains the refrigerant separation function while reducing the weight and bulk of individual tanks, allowing for more compact system configuration.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a category II or higher flash tank is used to meet minimum standards, then pressure and volume requirements are satisfied, but certification and testing become time consuming and costly

Engineering Contradiction:
Improvepressure and volume standardsVSAvoidmanufacturing cost and time
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By segmenting the flash tank system into multiple smaller tanks, each tank can be designed to meet lower certification categories with reduced pressure-times-volume ranges. This reduces the complexity and cost of certification and testing while still satisfying the overall system requirements for refrigerant separation.

Inventive Principle:
Principle #1Segmentation

3Reliability

If a single flash tank with large internal volume is used, then refrigerant separation is effective, but the flash tank is bulky and limits system configuration options

Engineering Contradiction:
Improverefrigerant separation efficiencyVSAvoidsystem configuration flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent divides the flash tank system into multiple smaller tanks that can be arranged in different configurations (series, parallel, or combination). This segmentation maintains effective refrigerant separation while providing flexibility in system design and installation, allowing the system to adapt to different space constraints and application requirements.

Inventive Principle:
Principle #1Segmentation

4Weight of moving object

If multiple flash tanks with reduced operating pressures and volumes are used, then weight and manufacturing costs are reduced, but system complexity increases

Engineering Contradiction:
Improvesystem weightVSAvoidflash tank system complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent combines multiple flash tanks into a unified flash tank system with interconnected first and second flash tanks. This merging approach distributes the separation function across multiple units while maintaining system-level simplicity through standardized connections and integrated operation, reducing overall weight and cost without excessively increasing complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 use of multiple flash tanks with optimized design and connections reduces weight, manufacturing costs, and allows for more compact system configurations while maintaining efficient refrigerant separation and phase control, enhancing overall system performance.

Implementation Method 1

A flash tank is generally placed between the expansion valve and an evaporator in a refrigeration system to separate and bypass any flash gas (refrigerant vapor) formed in the valve and, to separate a refrigerant vapor/liquid mixture at an intermediate pressure

Methodology Applied
Scientific EffectPhase separation: Two-Phase Flow

Implementation Method 2

separate and bypass any flash gas (refrigerant vapor) formed in the valve

Methodology Applied
Scientific EffectFlash gas formation: Joule-Thomson Effect

Data Source

PatentEP3862654B1Refrigerant vapor compression system with multiple flash tanks
Publication Date: 2024.01.31 CARRIER CORP
  • EP3862654B1 patent drawingFigure 1
  • EP3862654B1 patent drawingFigure 2A
  • EP3862654B1 patent drawingFigure 2B

AI summary

A refrigerant vapor compression system (100) comprising a plurality of components connected in a refrigerant flow circuit (120) by a plurality of refrigerant lines (120A, 120B, 120C, 120D, 120E), said components including: a compression device (104A, 104B); a refrigerant heat rejection heat exchanger (102); a first expansion device (108); a refrigerant heat absorption heat exchanger (106); and a flash tank system (110) having a first flash tank (10A) operably coupled to a second flash tank (10B) by a first connection (40A), the flash tank system (110) being disposed in the refrigerant flow circuit (120) between the refrigerant heat rejection heat exchanger (102) and the refrigerant heat absorption heat exchanger (106).