Compressor Agitation Element Homogenization

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Solution Overview

Problem

In household appliances like refrigerators and heat pumps, the solubility of refrigerant in lubricating oil reduces the amount of refrigerant available for heat transfer, leading to inefficiencies in energy interchange and lubrication issues, particularly when using oil mixtures with additives like nanoparticles or nanofluids.

Innovation Solution

A rotary compressor design featuring a rotating roller lubricated by a mixture of oil and refrigerant, with an oil sump and a propeller-like agitation element attached to the drive shaft to agitate the mixture, reducing solubility time and improving lubrication through forced homogenization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the refrigerant is soluble in the lubricating oil, then the lubrication function is improved, but the amount of refrigerant available for heat transfer is reduced

Engineering Contradiction:
Improvelubrication functionVSAvoidrefrigerant available for heat transfer
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies preliminary action by pre-agitating the oil-refrigerant mixture in the sump before the refrigerant enters the compression chamber. The agitation element stirs the mixture in advance, reducing solubility time and ensuring that refrigerant is quickly available for heat transfer once it leaves the sump, thus resolving the contradiction between maintaining lubrication and preserving heat transfer efficiency

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the refrigerant solubility in oil is increased, then the lubrication effectiveness is improved, but the energy interchange efficiency is reduced

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidenergy interchange efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The agitation element performs preliminary action by agitating the oil-refrigerant mixture before it enters the compression chamber. This pre-agitation reduces the time required for refrigerant to become available for heat transfer, thereby improving energy interchange efficiency while maintaining the lubrication benefits of refrigerant-soluble oil

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies the skipping principle by rapidly agitating the mixture to accelerate the release of refrigerant from the oil phase. This rushing through the solubility process minimizes the time refrigerant is bound in the oil, allowing it to quickly transition to the heat transfer phase, thus improving energy efficiency without compromising lubrication

Inventive Principle:
Principle #21Skipping (Rushing through)

3Quantity of substance

If the solubility time of refrigerant in oil is reduced, then the refrigerant availability for heat transfer is improved, but the lubrication homogeneity is worsened

Engineering Contradiction:
Improverefrigerant availabilityVSAvoidlubrication homogeneity
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The agitation element performs preliminary action by continuously agitating the oil-refrigerant mixture in the sump before the refrigerant is drawn into the compression chamber. This pre-agitation ensures homogeneous mixing of the lubrication components while simultaneously reducing solubility time, allowing refrigerant to be quickly available for heat transfer without compromising the homogeneity of the lubrication mixture

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The agitation element operates continuously to maintain continuous homogenization of the oil-refrigerant mixture. This continuous action ensures that the lubrication composition remains stable and homogeneous while also minimizing the time refrigerant remains dissolved in the oil, thus resolving the contradiction between refrigerant availability and lubrication homogeneity

Inventive Principle:
Principle #20Continuity of useful 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 design enhances the efficiency of household appliances by increasing the availability of refrigerant for heat transfer and improving lubrication, especially in oil mixtures with additives, by reducing solubility time and ensuring a homogeneous blend of oil and refrigerant.

Implementation Method 1

a rotating agitation element which is at least partly submerged in the mixture for agitating it. The agitation element is a propeller

Methodology Applied
Scientific EffectAgitation: Stirring

Implementation Method 2

the roller is lubricated by means of a mixture of oil and the refrigerant being dissolved in the oil

Methodology Applied
Scientific EffectSolubility: Solvation

Data Source

PatentEP3757393B1Compressor and household appliance
Publication Date: 2024.01.17 BOSCH SIEMENS HAUSGERATE GMBH
  • EP3757393B1 patent drawingFigure 1
  • EP3757393B1 patent drawingFigure 2
  • EP3757393B1 patent drawingFigure 3

AI summary

A compressor (10) for a household appliance (1), comprising a rotating roller (23) for compressing a gaseous phase (GR) of a refrigerant, wherein the roller (23) is lubricated by means of a mixture (M) of oil and the refrigerant being dissolved in the oil, an oil sump (25) for receiving the mixture (M), and a rotating agitation element (24) which is at least partly submerged in the mixture (M) for agitating it.