CO2 Refrigeration π-Type Silencer for Pressure Pulsation Reduction

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Solution Overview

Problem

Refrigeration systems using carbon dioxide as a refrigerant face increased pressure pulsation due to higher density and sound speed, which existing methods have not adequately addressed.

Innovation Solution

A π-type silencer design with a first and second silencing space and a communication path extending between them, allowing for reduced pressure pulsation and flexible configuration options, including the use of mesh members to prevent reflection waves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If carbon dioxide is employed as a refrigerant, then refrigeration system efficiency is improved, but pressure pulsation becomes larger

Engineering Contradiction:
Improverefrigeration system efficiencyVSAvoidpressure pulsation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The silencer is divided into multiple silencing chambers (first silencing chamber, second silencing chamber, third silencing chamber) connected in series, with each chamber providing incremental pressure pulsation reduction. This segmentation allows the system to effectively dampen pressure pulsation while maintaining refrigeration efficiency with carbon dioxide refrigerant.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The refrigerant passage is nested within the silencer structure, with the passage running through the center of multiple concentric silencing chambers. This nested configuration maximizes the silencing effect within a compact volume while maintaining efficient heat exchange and refrigerant flow.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If conventional silencer design is used, then manufacturing is simpler, but pressure pulsation reduction is insufficient

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidpressure pulsation
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The silencer is divided into multiple silencing chambers (first silencing chamber, second silencing chamber, third silencing chamber) connected in series, with each chamber providing incremental pressure pulsation reduction. This segmentation allows the system to effectively dampen pressure pulsation while maintaining refrigeration efficiency with carbon dioxide refrigerant.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention optimizes specific parameters including the cross-sectional area ratio between refrigerant passage and silencing chambers (0.1 to 0.3), the length-to-diameter ratio of silencing chambers (2 to 5), and the number of chambers (2 to 4) to achieve effective pressure pulsation reduction while maintaining manufacturability.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If π-type silencer with side-by-side chambers is used, then pressure pulsation is reduced, but device length increases

Engineering Contradiction:
Improvepressure pulsationVSAvoidsilencer length
Core Design Contradiction:
Object-generated harmful factorsVSLength of stationary object

Solution Approach 1:

The invention transitions from a linear arrangement of silencing chambers to a three-dimensional nested configuration where chambers are arranged concentrically around a central refrigerant passage. This dimensional change reduces the overall length of the silencer while maintaining the pressure pulsation reduction effect through multiple chambers.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Reliability

If refrigerant passage extends into silencing space, then oil collection is prevented, but manufacturing complexity increases

Engineering Contradiction:
Improveoil collection preventionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The refrigerant passage is nested within the silencer structure, with the passage running through the center of multiple concentric silencing chambers. This nested configuration maximizes the silencing effect within a compact volume while maintaining efficient heat exchange and refrigerant flow.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 π-type silencer effectively reduces pressure pulsation and prevents refrigerating machine oil collection, enabling a more compact design and cost-effective manufacturing while maintaining efficient refrigeration operations.

Implementation Method 1

a communication path extending from the lower end of the first silencing space and through the outside of the first silencing space to the lower end of the second silencing space and communicating with the second silencing space

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Implementation Method 2

the use of mesh members to prevent reflection waves

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP2058610B1Refrigeration system
Publication Date: 2019.03.06 DAIKIN INDUSTRIES LTD
  • EP2058610B1 patent drawingFigure 1
  • EP2058610B1 patent drawingFigure 2
  • EP2058610B1 patent drawingFigure 3

AI summary

It is an object of the present invention to sufficiently reduce the pressure pulsation in a refrigeration system that employs carbon dioxide or the like as a refrigerant. A refrigeration system (1) according to the present invention comprises a first refrigerant passage (204), a π-type silencer (20, 20a), and a second refrigerant passage (205). The π-type silencer has a first silencing space (201), a second silencing space (202), and a communication path (203, 203a). The first silencing space communicates with the first refrigerant passage. The second silencing space is disposed below the first silencing space. The communication path extends from the lower end of the first silencing space to the outside of the first silencing space and communicates with the second silencing space. The second refrigerant passage extends from the lower end of the second silencing space.