Heat-Pump Oil Balance Pipe Design for Multi-Compressor Oil Recovery

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Solution Overview

Problem

Existing heat-pump systems face challenges in efficiently recovering and balancing oil between compressors, leading to potential oil imbalances and operational inefficiencies.

Innovation Solution

The heat-pump system incorporates a dual compressor setup with an electromotive compressor and a gas engine compressor, along with oil balance pipes and separators, to facilitate the recovery and distribution of oil between the compressors, ensuring balanced oil levels and efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a gas engine compressor is used to compress a large amount of refrigerant, then the compressor capacity is improved, but oil separation from refrigerant becomes difficult and the compressor lacks oil

Engineering Contradiction:
Improvecompressor capacityVSAvoidoil supply to compressor
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

An oil separator is introduced as an intermediary device between the compressor and refrigerant flow. The oil separator captures oil from the refrigerant stream and returns it to the compressor, ensuring continuous oil supply while allowing the compressor to operate at high capacity with large refrigerant flow

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system recovers oil that would otherwise be discarded with the refrigerant exhaust. The oil separator extracts oil from the refrigerant stream and the oil return mechanism delivers it back to the compressor, preventing oil loss and ensuring continuous lubrication

Inventive Principle:
Principle #34Discarding and recovering

2Productivity

If oil is not easily separated from refrigerant, then the refrigerant circulation is maintained, but the compressor experiences oil deficiency

Engineering Contradiction:
Improverefrigerant circulationVSAvoidcompressor oil supply
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The oil separator acts as a mediator that decouples refrigerant circulation from oil transport. It allows refrigerant to flow freely through the system while intercepting and separating oil, then returning the separated oil to the compressor through dedicated return pathways

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system segments the refrigerant-oil mixture into separate streams. The oil separator divides the combined flow into refrigerant (continuing through the heat pump cycle) and oil (returned to compressor), enabling independent control of refrigerant circulation and oil supply

Inventive Principle:
Principle #1Segmentation

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 configuration allows for effective oil recovery and distribution, preventing oil imbalances and ensuring that neither compressor experiences excessive oil storage nor oil deficiency, thereby enhancing the overall operational efficiency of the heat-pump system.

Implementation Method 1

since oil is not easily separated from refrigerant circulating during the heat pump cycle

Methodology Applied
Scientific EffectSeparation:

Implementation Method 2

a compressor having a large capacity for an industrial facility or for conditioning air in a large building... in order to operate a compressor for compressing a lot of refrigerant to a gas having a high temperature and a high pressure

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

it is possible to produce hot water by using a heat source obtained through a heat exchange between refrigerant for the heat pump cycle and a certain heat storage medium

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3102894B1Heat-pump system
Publication Date: 2025.03.05 LG ELECTRONICS INC
  • EP3102894B1 patent drawingFigure 1~2
  • EP3102894B1 patent drawingFigure 3~4
  • EP3102894B1 patent drawingFigure 5

AI summary

Provided is a heat-pump system including a plurality of compressors, wherein the plurality of compressors includes a first compressor and a second compressor that compress refrigerant, an oil separator provided on a discharge side of the plurality of compressors to separate oil mixed with refrigerant compressed by the plurality of compressors, an oil separation pipe extended from the oil separator to allow the plurality of compressors to recover oil, and a compressor side oil balance pipe extended from the second compressor to allow the first compressor to recover oil stored in the second compressor.