Rotary Compressor Discharge Muffler Volume Optimization

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Solution Overview

Problem

Rotary compressors using refrigerants with no chlorine atoms and a small global warming potential, such as hydrofluoroolefins, face challenges with reduced refrigerant density leading to increased flow rates and pressure losses, which result in reduced efficiency and potential refrigerant decomposition due to excessive compression or re-expansion.

Innovation Solution

The spatial volume of the discharge muffler is adjusted based on the density of the inhaled refrigerant to minimize pressure loss and prevent excessive temperature increases, ensuring a reliable and efficient compressor operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional rotary compressor designed for HFC410A is used with hydrofluoroolefin refrigerant, then the compressor structure remains simple and conventional, but pressure loss increases and efficiency decreases due to reduced refrigerant density

Engineering Contradiction:
Improvepressure lossVSAvoidrefrigerant compatibility
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent modifies the spatial volume of the discharge muffler based on the density characteristics of hydrofluoroolefin refrigerant. Specifically, the discharge muffler volume is increased compared to conventional compressors designed for HFC410A, which compensates for the lower density of hydrofluoroolefin and reduces pressure loss while maintaining efficient refrigerant flow.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the discharge muffler volume is increased to accommodate lower density refrigerant, then pressure loss is reduced, but the compressor overall size increases

Engineering Contradiction:
Improvepressure lossVSAvoidcompressor size
Core Design Contradiction:
Loss of energyVSVolume of moving object

Solution Approach 1:

The patent applies local quality by specifically increasing the volume of the discharge muffler portion while keeping other compressor components unchanged. This localized modification targets the specific area where pressure loss occurs due to low-density refrigerant flow, rather than increasing the entire compressor size.

Inventive Principle:
Principle #3Local quality

3Reliability

If the conventional discharge muffler is used with hydrofluoroolefin refrigerant, then the compressor structure remains compact, but refrigerant decomposition occurs due to excessive compression and temperature increase

Engineering Contradiction:
Improverefrigerant stabilityVSAvoiddischarge muffler volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent applies preliminary anti-action by pre-configuring the discharge muffler with an appropriately increased volume before the refrigerant enters. This prevents the harmful effects of excessive compression and temperature rise that would otherwise cause hydrofluoroolefin decomposition, by providing sufficient space for smooth refrigerant flow and pressure equalization.

Inventive Principle:
Principle #9Preliminary anti-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 approach results in a highly-efficient and durable rotary compressor with reduced pressure loss and minimized refrigerant decomposition, maintaining performance while using refrigerants with low global warming potential.

Implementation Method 1

a spatial volume of the discharge muffler is determined depending on a density of the refrigerant, thereby making it possible to provide a rotary compressor capable of positively reducing a pressure loss

Methodology Applied
Scientific EffectPressure loss reduction: Pressure Drop

Implementation Method 2

an inhaled refrigerant is caused to receive heat, which may in turn cause an excessive increase in temperature of a discharged refrigerant

Methodology Applied
Scientific EffectCompression heating: Adiabatic Heating

Data Source

PatentEP2565459B1Rotary compressor
Publication Date: 2016.09.21 PANASONIC HOLDINGS CORP
  • EP2565459B1 patent drawingFigure 1~2
  • EP2565459B1 patent drawingFigure 3~5
  • EP2565459B1 patent drawingFigure 6~7

AI summary

A rotary compressor contains, as a refrigerant, a single-component refrigerant comprising hydrofluoroolefin having a carbon-carbon double bond or a mixture refrigerant comprising this hydrofluoroolefin and hydrofluorocarbon having no double bond. The rotary compressor includes a compression mechanism 3 having a compression chamber 39 for increasing a pressure of the refrigerant inhaled through the suction port, a discharge port 38 for discharging the refrigerant, the pressure of which has been increased in the compression chamber, and a discharge muffler 37 to cover the discharge port. A spatial volume of the discharge muffler is determined depending on a density of the refrigerant, thereby making it possible to provide a rotary compressor capable of positively reducing a pressure loss associated with an increase in flow rate of the refrigerant, preventing a rise in discharge temperature, and restraining a reduction in reliability or durability that may be caused by decomposition of the refrigerant.