Oil Separator Sizing and Common Sump for Supermarket Refrigeration

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Solution Overview

Problem

Supermarket refrigeration systems face inefficiencies due to excessive oil flow, which interferes with the operation of compressors and refrigerant circulation, necessitating effective oil management to maintain optimal performance.

Innovation Solution

The system incorporates oil separators with critical charging to ensure both compressors receive adequate oil supplies, with oil separators sized to handle volumes between 100% and 250% of the initial oil charge, and an oil management system that allows oil transfer between compressors via an oil line and valve to prevent accumulation and maintain efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If oil separators are used to remove oil from refrigerant, then efficient operation of the refrigeration system is improved, but oil distribution between multiple compressors becomes unbalanced

Engineering Contradiction:
Improverefrigeration system efficiencyVSAvoidoil supply balance to compressors
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A common oil sump acts as an intermediary reservoir that receives oil from both compressors and distributes it back to them. The oil separator separates oil from refrigerant, returns it to the common oil sump, which then supplies oil to both compressors, ensuring balanced distribution while maintaining efficient operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent merges the oil supply systems of multiple compressors into a single common oil sump. Instead of each compressor having separate oil circulation, the oil separators from both compressors discharge to the shared sump, which then distributes oil to both compressors, ensuring balanced oil supply while maintaining system efficiency.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If oil is circulated to lubricate compressor components, then compressor operation is improved, but excessive oil flow interferes with refrigerant circulation

Engineering Contradiction:
Improvecompressor lubricationVSAvoidrefrigerant circulation efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The oil separator extracts oil from the refrigerant stream after compression. By removing oil that would otherwise interfere with refrigerant circulation, the system maintains adequate lubrication for compressor components while preventing excessive oil flow from affecting refrigeration efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The oil separator creates local oil return to the compressor suction line, ensuring that lubrication is provided exactly where needed (at the compressor) rather than allowing oil to circulate throughout the entire refrigeration system where it would interfere with refrigerant flow.

Inventive Principle:
Principle #3Local quality

3Reliability

If oil separators are sized to hold adequate oil supply, then compressor oil availability is improved, but system complexity increases

Engineering Contradiction:
Improvecompressor oil availabilityVSAvoidoil separator sizing and configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The common oil sump serves multiple functions: it acts as an oil reservoir for both compressors, a mixing chamber for oil from different sources, and a distribution point for balanced oil supply. This multi-functionality reduces the need for separate oil management systems for each compressor, simplifying the overall configuration while ensuring adequate oil availability.

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

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 solution ensures efficient operation by preventing oil depletion in one compressor while maintaining adequate oil supply to the other, reducing maintenance and energy losses, and simplifying the system by eliminating the need for pumps and secondary refrigerants.

Implementation Method 1

A first portion of the first oil separator below the first horizontal plane is configured to collect separated oil

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3568650B1Oil management for micro booster supermarket refrigeration system
Publication Date: 2022.06.01 EMERSON CLIMATE TECHNOLOGIES INC
  • EP3568650B1 patent drawingFigure 1
  • EP3568650B1 patent drawingFigure 2~5
  • EP3568650B1 patent drawingFigure 6~7

AI summary

A refrigeration system includes first and second compressors and an oil separator. The oil separator includes an inlet for receiving refrigerant and oil from the first compressor, a refrigerant outlet, and an oil outlet. The oil separator separates the oil from the refrigerant. A portion of the oil separator below a horizontal plane intersecting the refrigerant outlet collects separated oil and has a volume equal to a first compressor oil supply. The first compressor oil supply is greater than or equal to 100% and less than or equal to 250% of a first compressor initial oil charge. The first compressor receives oil from the oil outlet when an amount of oil in the portion is less than or equal to the first compressor oil supply. The second compressor receives oil from the refrigerant outlet when the amount of oil in the portion is greater than the first compressor oil supply.