CO2 Interstage Cooling Using Storage Tank Cold Energy

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Solution Overview

Problem

Current dry cleaning systems using carbon dioxide solvents face inefficiencies due to complex cooling units with moving parts, high energy consumption, and supercooling issues, leading to increased maintenance needs and costs.

Innovation Solution

A cooling unit utilizing cooled fluid from other parts of the system to cool the gas between compressor stages, eliminating the need for external energy sources and reducing mechanical complexity by leveraging internal temperature differences for efficient heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If an air cooled intercooler with fan is used between compressor stages, then the gas temperature is controlled, but the device complexity increases and energy consumption increases

Engineering Contradiction:
Improvegas temperatureVSAvoidcooling unit complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The system uses the cold CO2 from the storage tank to cool the compressed gas between stages, eliminating the need for external cooling devices. The cold storage CO2 serves the dual purpose of storage and cooling, making the system self-sufficient and reducing complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The CO2 in the storage tank performs multiple functions: it serves as the cleaning solvent for the washing process and simultaneously acts as the cooling medium for the compressor intercooler. This multi-functionality eliminates dedicated cooling equipment.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If an air cooled intercooler with fan is used between compressor stages, then the gas temperature is controlled, but energy consumption increases

Engineering Contradiction:
Improvegas temperatureVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The system uses the cold CO2 from the storage tank to cool the compressed gas between stages, eliminating the need for external cooling devices. The cold storage CO2 serves the dual purpose of storage and cooling, making the system self-sufficient and reducing complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system converts the cold temperature of the stored CO2, which would otherwise be wasted, into a useful cooling resource for the compressor intercooler. This transforms a potentially harmful low temperature into a beneficial cooling effect.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Temperature

If the fan is constantly operating, then cooling is maintained, but energy consumption increases

Engineering Contradiction:
Improvecooling effectivenessVSAvoidelectrical energy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The system uses the cold CO2 from the storage tank to cool the compressed gas between stages, eliminating the need for external cooling devices. The cold storage CO2 serves the dual purpose of storage and cooling, making the system self-sufficient and reducing complexity.

Inventive Principle:
Principle #25Self-service

4Stress or pressure

If supercooled fluid is stored in the storage tank, then pressure is controlled, but the fluid temperature becomes too low for optimal washing

Engineering Contradiction:
Improvestorage tank pressureVSAvoidfluid temperature for washing
Core Design Contradiction:
Stress or pressureVSTemperature

Solution Approach 1:

The system divides the CO2 flow into separate paths: one path takes CO2 from the storage tank to the cleaning chamber for washing, while another path takes CO2 through the compressor and intercooler. This segmentation allows temperature control for each function independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system pre-cools the compressed CO2 between compression stages using the intercooler before it enters the storage tank. This preliminary cooling action ensures that the CO2 stored is at an optimal temperature, preventing excessive supercooling.

Inventive Principle:
Principle #10Preliminary action

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 solution reduces energy consumption, minimizes maintenance needs, and maintains optimal solvent temperatures for washing, resulting in a simpler, cost-effective, and more reliable dry cleaning process.

Implementation Method 1

a tube section for conveying the fluid from the first compressor stage to the second compressor stage, arranged such that the fluid in the tube section is fluidly associated with the fluid in the device and cooled by the cooled fluid in the device

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP2576885B1Cooling device and method therefore for co2 washing machines
Publication Date: 2016.08.24 ELECTROLUX LAUNDRY SYST SWEDEN
  • EP2576885B1 patent drawingFigure 1~2
  • EP2576885B1 patent drawingFigure 3~4
  • EP2576885B1 patent drawingFigure 5~6

AI summary

The present invention relates to a cooling unit for cooling fluid in a dry cleaning system and a method therefore. The cooling unit (12) comprises a device (1, 7, 8) containing cooled fluid such as carbon dioxide, and a tube section (11) for conveying the fluid from a first compressor stage (2) to a second compressor stage (3), arranged so that the fluid in the tube section (11) is cooled by the cooled fluid in the device (1, 7, 8).