Heat Pump Muffler with Angled Ports for Compressor Noise Attenuation

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Solution Overview

Problem

Heat pumps, such as those used in air conditioners, face challenges in noise attenuation due to the transmission of compressor noise through refrigerant piping, which is not effectively reduced by existing mufflers, especially in domestic and work environments where noise needs to be minimized. The noise attenuation is influenced by the muffler's size and length, and the variability of refrigerant state affects sound dampening, leading to resonance issues.

Innovation Solution

A heat pump design incorporating a muffler with a pressure pulsation reducing space that changes the flow direction of refrigerant, utilizing a non-linear shape such as a cylinder or sphere, and offset or angled port axes to maximize sound reflections and energy loss, ensuring effective noise reduction across various frequencies without significant dependence on refrigerant state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the area of the enlarged section of the muffler is increased to improve noise attenuation, then the noise attenuation performance is improved, but the device becomes too large for installation in domestic and work environments

Engineering Contradiction:
Improvenoise attenuationVSAvoidmuffler size
Core Design Contradiction:
Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The muffler is divided into multiple sections including an inlet section, a reflection section with enlarged area, and an outlet section. The reflection section is further segmented into multiple reflection surfaces arranged at different angles, allowing noise attenuation functionality to be distributed across multiple smaller reflective elements rather than requiring one large enlarged section.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention utilizes three-dimensional spatial arrangement by positioning multiple reflection surfaces at different angular orientations around the refrigerant flow path. This multi-dimensional configuration maximizes noise reflection and attenuation within a compact volume, effectively utilizing space in multiple directions rather than simply enlarging the muffler in one dimension.

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

2Object-affected harmful factors

If the length of the muffler is increased to improve noise attenuation, then the noise attenuation performance is improved, but the muffler becomes too long for installation in lot of domestic and work environments

Engineering Contradiction:
Improvenoise attenuationVSAvoidmuffler length
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The muffler structure is segmented into functional sections (inlet, reflection, outlet) with the reflection section containing multiple angled surfaces. This segmentation allows the noise attenuation function to be achieved through multiple small-scale reflections rather than requiring a single long passage, significantly reducing the overall length while maintaining attenuation effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The muffler incorporates curved and angled reflection surfaces instead of straight linear paths. The refrigerant flow follows a curved trajectory through the reflection section, bouncing off multiple angled surfaces. This curved path design achieves effective noise attenuation within a compact length by utilizing spatial curvature rather than linear extension.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Object-affected harmful factors

If the refrigerant flow direction is changed multiple times to improve noise attenuation, then the noise attenuation performance is improved, but the device complexity increases

Engineering Contradiction:
Improvenoise attenuationVSAvoidmuffler structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Multiple reflection surfaces are merged into a single integrated reflection section of the muffler housing. The various angled surfaces work together as one unified structure to redirect refrigerant flow multiple times, achieving complex noise attenuation functionality without requiring multiple separate components or complex assembly.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The reflection surfaces utilize curved and angled geometries that naturally guide the refrigerant flow through multiple direction changes. The curved surfaces create smooth flow transitions that enforce multiple reflections without requiring sharp edges or complex internal structures, simplifying the overall design while maintaining effective noise attenuation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 proposed design significantly reduces noise volume by enforcing multiple reflections and direction changes in the refrigerant flow, converting sound energy into heat, thereby minimizing noise transmission regardless of refrigerant conditions, while allowing for flexible and efficient muffler design.

Implementation Method 1

Noise sound waves carried by the refrigerant entering through the first port 11' will (partially) impinge on the enlarged section A of the muffler 10'. This reflection will cause them to lose some of their energy, which will lead to an attenuation of the noise.

Methodology Applied
Scientific EffectSound wave reflection: Reflection

Implementation Method 2

This reflection will cause them to lose some of their energy, which will lead to an attenuation of the noise.

Methodology Applied
Scientific EffectEnergy dissipation: Damping

Implementation Method 3

The proposed design significantly reduces noise volume by enforcing multiple reflections and direction changes in the refrigerant flow, converting sound energy into heat

Methodology Applied
Scientific EffectSound energy conversion to heat: Viscous Heating

Data Source

PatentEP3828413B1Heat pump comprising a muffler
Publication Date: 2023.03.22 DAIKIN EURO
  • EP3828413B1 patent drawingFigure 1~5
  • EP3828413B1 patent drawingFigure 6~8b
  • EP3828413B1 patent drawingFigure 9

AI summary

The invention comprises a heat pump comprising a heat source heat exchanger, a compressor, a utilization side heat exchanger and an expansion valve connected by refrigerant piping; and a muffler having first and second ports and a pressure pulsation reducing space, the pressure pulsation reducing space being in fluid communication with at least the first port and the second port, wherein the first and second ports are respectively connected to the refrigerant piping, characterized in that a first centre axis of the first port and a second centre axis of the second port are oriented so that a flow direction of refrigerant flowing in the refrigerant piping changes at least once between the first port and the second port.