Parallel Compressor Climate System Without Oil Equalization

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Solution Overview

Problem

Conventional climate systems with multiple compressors face challenges in efficiently managing compressor oil entrainment, leading to uneven lubrication distribution and reduced efficiency, particularly in parallel compressor configurations, which often require complex and costly oil equalization systems.

Innovation Solution

A climate system with parallel compressors that lacks an oil equalization system, utilizing a controller to independently manage compressor operation and oil draw-back by operating compressors at low speed ranges before shutdown to redistribute oil, allowing for flexible compressor sizing and mounting configurations, and integrating with existing air conditioning systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an oil equalization system is used to manage compressor oil in parallel compressor configurations, then lubrication distribution is improved, but system complexity and cost increase

Engineering Contradiction:

Improvelubrication distributionVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the oil equalization system from the parallel compressor configuration, extracting the problematic component that caused complexity while maintaining reliable lubrication distribution through independent compressor control and strategic shutdown sequencing

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Each compressor serves its own lubrication needs independently through controlled shutdown sequences that allow oil to drain back into the compressor crankcase, eliminating the need for external equalization systems and enabling self-regulating lubrication distribution

Inventive Principle:

Principle #25Self-service

2Productivity

If compressors are arranged in parallel to increase cooling capacity, then productivity is improved, but oil management complexity and efficiency deteriorate

Engineering Contradiction:

Improvecooling capacityVSAvoidoil management complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The system dynamically controls the operation and shutdown sequence of parallel compressors based on real-time conditions, allowing flexible oil management that adapts to varying cooling demands while maintaining simplicity in the overall system architecture

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Compressors are periodically shut down in a controlled sequence that allows oil to drain back into the crankcase, creating a periodic self-regulating oil distribution mechanism that simplifies parallel compressor oil management while maintaining high cooling capacity

Inventive Principle:

Principle #19Periodic action

3Adaptability or versatility

If compressors are mounted at different levels or heights for flexible installation, then adaptability is improved, but uneven oil distribution occurs

Engineering Contradiction:

Improvemounting flexibilityVSAvoidoil distribution

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary controlled shutdown of compressors in a specific sequence before full shutdown, allowing oil to drain back into the crankcase while the compressors are still positioned, ensuring proper oil distribution regardless of mounting height differences

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the operational parameters of the compressors during shutdown, using controlled speed reduction and staged shutdown sequences to manage oil flow and distribution, enabling flexible mounting configurations without compromising lubrication reliability

Inventive Principle:

Principle #35Parameter changes

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 simplifies system design, reduces costs, enhances flexibility, and improves efficiency by allowing compressors of different sizes and orientations, while maintaining effective lubrication and thermal management without the need for complex oil equalization systems.

Implementation Method 1

The controller is electrically coupled to the first and second compressors and configured to automatically and independently control operation of the first and second compressors to draw back compressor oil to the first and second compressors

Methodology Applied

Scientific EffectCompressor oil draw-back:

Data Source

PatentUS11479086B2Multi-compressor climate system

Publication Date: 2022.10.25 BERGSTROM INC

AI summary

Disclosed are climate systems and methods for control the climate systems. A climate system includes a plurality of compressors, a first heat exchanger disposed downstream of the compressors and a second heat exchanger disposed downstream of the first heat exchanger. The compressors and heat exchangers are fluidly connected by refrigerant lines to form a refrigerant circuit. The climate system also includes a controller that controls the operation of the compressors to draw back lubricant to the compressors without use of an oil equalization system.