Refrigeration system with oil control system

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Solution Overview

Problem

CO2 refrigeration systems face challenges in oil management, as existing systems either require active oil control with separators or passive systems that mix oil with refrigerant, leading to inefficiencies and potential compressor imbalance.

Innovation Solution

A semi-passive oil control system using oil equalization lines and valves to balance oil distribution among compressors, with a controller managing oil flow based on threshold measurements to ensure optimal oil levels, preventing oil shortages or excesses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If active oil control systems are used with oil separators to remove oil from refrigerant, then oil delivery to compressors is improved, but device complexity increases

Engineering Contradiction:
Improveoil delivery to compressorsVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the oil separation function from the main refrigeration cycle by using a dedicated oil separator that removes oil from the refrigerant stream. This separated oil is then returned to the compressors through a separate oil return line, ensuring reliable oil delivery without requiring complex active control systems integrated into each compressor pathway.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The oil separator serves multiple functions: it separates oil from refrigerant, stores the separated oil, and provides a return pathway to the compressors. This multi-functional component reduces overall system complexity compared to having separate active control mechanisms at each compressor.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If passive oil control systems are used without oil separators, then device complexity is reduced, but oil distribution balance among compressors deteriorates

Engineering Contradiction:
Improvesystem complexityVSAvoidoil distribution balance
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The oil separator acts as an intermediary component that mediates between the refrigerant stream and the compressors. It collects oil from the refrigerant and provides it through a dedicated return line, ensuring balanced oil distribution to all compressors without requiring complex active control mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If direct oil delivery to each compressor is implemented, then oil supply reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improveoil supply to compressorsVSAvoidnumber of oil lines and control valves
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the oil delivery function into a single centralized oil separator and return line system that serves all compressors. This consolidated approach ensures reliable oil supply to each compressor through the common return line while avoiding the complexity of individual oil delivery systems for each compressor.

Inventive Principle:
Principle #5Merging (Combining)

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 ensures balanced oil distribution among compressors, maintaining system efficiency and preventing damage from oil shortages, while reducing the need for direct oil delivery to each compressor, thus enhancing overall refrigeration system performance.

Implementation Method 1

an oil separator configured to separate oil from the CO2 refrigerant

Methodology Applied
Scientific EffectPhase separation: Density Gradient

Implementation Method 2

the oil mixes with the CO2 refrigerant in the suction line before reaching the compressors

Methodology Applied
Scientific EffectMixing: Diffusion

Data Source

PatentEP3572741B1Refrigeration system with oil control system
Publication Date: 2024.03.27 HILLPHOENIX INC
  • EP3572741B1 patent drawingFigure 1
  • EP3572741B1 patent drawingFigure 2
  • EP3572741B1 patent drawingFigure 3

AI summary

A CO2 refrigeration system (100) includes a plurality of compressors (14) configured to circulate a CO2 refrigerant, a suction line (17) configured to deliver the CO2 refrigerant to the compressors (14), an oil separator (31) configured to separate oil from the CO2 refrigerant, and an oil return line (33) configured to deliver the oil from the oil separator (31) to the suction line (17). The oil mixes with the CO2 refrigerant in the suction line (17) before reaching the compressors (14).