Refrigeration system and the lubrication method thereof

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Solution Overview

Problem

In refrigeration systems, existing lubrication methods either use lubricating oil that affects heat exchange performance or require complex management of refrigerant extraction for oil-free systems, necessitating a more efficient and effective lubrication method using refrigerant.

Innovation Solution

A refrigeration system with pre- and post-lubrication flow paths that allow selective extraction of refrigerant from the condenser or evaporator to lubricate the compressor, using valves and flow channels to manage refrigerant flow based on real-time conditions, ensuring adequate lubrication and minimizing disruption to the system's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lubricating oil is filled into the system to lubricate the compressor, then the service life of the device is improved, but the heat exchange performance of the refrigerant is affected

Engineering Contradiction:
Improveservice life of the deviceVSAvoidheat exchange performance degradation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention extracts the harmful lubricating oil from the refrigeration system and replaces it with refrigerant for lubrication. The system uses the refrigerant itself, which is already present in the system, to lubricate the compressor bearings through specially designed flow paths, thereby eliminating the contamination of refrigerant with oil and maintaining heat exchange performance while still providing adequate lubrication.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary mechanism - a dedicated lubrication flow path with control valves - that enables the refrigerant to serve dual purposes: both refrigeration and lubrication. This intermediary structure allows selective delivery of refrigerant to the compressor for lubrication without allowing it to mix with the main refrigerant circuit in a harmful manner.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If refrigerant is extracted to lubricate the compressor in an oil-free system, then the heat exchange performance is maintained, but the system complexity increases due to additional flow path management

Engineering Contradiction:
Improveheat exchange performanceVSAvoidflow path management complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The invention segments the refrigeration system into distinct functional flow paths: a main refrigeration cycle and a separate lubrication flow path. This segmentation allows independent control of refrigerant flow for different purposes. The lubrication flow path includes specific valves (such as a three-way valve and a two-way valve) that can independently regulate refrigerant delivery to the compressor without interfering with the main refrigeration cycle.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention employs dynamic control through valves that can adjust refrigerant flow based on real-time operating conditions. The three-way valve and two-way valve work together to dynamically regulate the amount of refrigerant extracted for lubrication, ensuring adequate lubrication while minimizing disruption to the refrigeration cycle. This dynamic adjustment capability allows the system to adapt to varying load conditions and maintain optimal performance.

Inventive Principle:
Principle #15Dynamics

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 system achieves effective lubrication of compressor bearings in various conditions, enhancing the service life and reliability of the refrigeration system while maintaining smooth operation and optimal heat exchange performance.

Implementation Method 1

part of the liquid refrigerant is extracted at a certain position of the refrigeration system and delivered to a compressor

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a condenser, an evaporator, and a lubrication circuit

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

part of the liquid refrigerant is extracted at a certain position of the refrigeration system and delivered to a compressor, so as to lubricate a bearing in the compressor

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3513135B1Refrigeration system and the lubrication method thereof
Publication Date: 2024.07.31 CARRIER CORP
  • EP3513135B1 patent drawingFigure 1~2
  • EP3513135B1 patent drawingFigure 3~4
  • EP3513135B1 patent drawingFigure 5~6

AI summary

A refrigeration system and a lubricating method thereof. The refrigeration system (100) includes: a compressor (110), a condenser (120), an evaporator (130), and a lubrication circuit (200), the lubrication circuit including a post-lubrication flow path (230,240,260) connected from the compressor into the condenser and the evaporator respectively; and a pre-lubrication flow path (210,220,250) connected from the condenser and the evaporator into the compressor respectively; wherein after flowing from the condenser via the pre-lubrication flow path to the compressor for lubrication, a part of refrigerant for lubrication can flow back to the evaporator via the post-lubrication flow path; or after flowing from the evaporator via the pre-lubrication flow path to the compressor for lubrication, the part of refrigerant for lubrication can flow back to the condenser via the post-lubrication flow path.