Refrigeration system

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Solution Overview

Problem

Existing refrigeration systems, both oil-lubricated and oil-free, face inefficiencies in energy usage and structural complexity, which can be improved for enhanced performance.

Innovation Solution

The refrigeration system incorporates a two-stage compressor with an ejector to mix high-pressure and low-pressure refrigerant into a medium-pressure gas-liquid two-phase refrigerant, which is then separated into gas-phase and liquid-phase refrigerants for efficient compression and cooling, and includes an oil tank for filtering and delivering lubricant oil to the compressor bearings in oil-lubricated systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If an economizer and expansion valve are configured in the refrigeration system to improve energy efficiency, then the energy efficiency coefficient is improved, but the system structure becomes more complex

Engineering Contradiction:
Improveenergy efficiency coefficientVSAvoidsystem structure
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent combines the economizer and expansion valve into an integrated component structure, where the expansion valve body incorporates the economizer functionality. This merging eliminates the need for separate economizer components and reduces the number of independent parts in the system, thereby simplifying the overall structure while maintaining the energy efficiency improvements provided by the economizer functionality.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If an additional oil return system with ejectors and oil tank is added to oil-lubricated compressors, then the compressor bearing lubrication is improved, but the system structure becomes more complex

Engineering Contradiction:
Improvecompressor bearing lubricationVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The ejector component is designed to perform multiple functions: it serves as part of the oil return system to extract oil from the refrigerant, while simultaneously functioning as an expansion device for the refrigerant. The oil tank is integrated with the system to provide both oil storage and filtration functions. This multi-functionality reduces the need for separate dedicated components, thereby simplifying the overall system structure while maintaining reliable compressor bearing lubrication.

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

3Productivity

If multiple ejectors are arranged in parallel to improve oil extraction efficiency, then the oil return performance is improved, but the device complexity increases

Engineering Contradiction:
Improveoil extraction efficiencyVSAvoidnumber of ejectors
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system divides the oil extraction function into multiple parallel ejector units, each handling a portion of the refrigerant flow. This segmentation allows for improved overall oil extraction efficiency as each ejector operates within optimal flow parameters. The modular parallel arrangement enables independent optimization of each ejector unit while achieving superior collective performance compared to a single large ejector.

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 simplifies the system structure, reduces manufacturing costs, and enhances energy efficiency by utilizing pressure differences and double filtration to ensure stable and pure oil lubrication, thereby improving overall system performance.

Implementation Method 1

an ejector configured to eject low-pressure refrigerant from the evaporator by means of high-pressure refrigerant from the condenser and to mix them into medium-pressure gas-liquid two-phase refrigerant

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

a separator configured to separate the medium-pressure gas-liquid two-phase refrigerant from the ejector into gas-phase refrigerant and liquid-phase refrigerant

Methodology Applied
Scientific EffectPhase separation: Two-Phase Flow

Implementation Method 3

to deliver the liquid-phase refrigerant separated to a motor housing of the compressor for cooling a rotor and a stator in the motor housing by flash evaporation

Methodology Applied
Scientific EffectFlash evaporation: Flash Evaporation

Data Source

PatentEP4286771A1Refrigeration system
Publication Date: 2023.12.06 CARRIER CORP
  • EP4286771A1 patent drawingFigure 1
  • EP4286771A1 patent drawingFigure 2
  • EP4286771A1 patent drawingFigure 3

AI summary

The present invention relates to a refrigeration system (100). The refrigeration system comprises: a main flow path comprising a compressor (110), a condenser (120), a throttling device (130) and an evaporator (140), wherein the compressor (110) comprises at least a first compression stage and a second compression stage; and the refrigeration system (100) further comprises: an ejector (150) configured to eject low-pressure refrigerant from the evaporator (140) by means of high-pressure refrigerant from the condenser (220) and to mix them into medium-pressure gas-liquid two-phase refrigerant; and a separator (160) configured to separate the medium-pressure gas-liquid two-phase refrigerant from the ejector (150) into gas-phase refrigerant and liquid-phase refrigerant, to deliver the gas-phase refrigerant separated to a gas supply port (114) between a fluid outlet of the first compression stage and a fluid inlet of the second compression stage in the compressor (110), and to deliver the liquid-phase refrigerant separated to a motor housing (113) of the compressor for cooling a rotor and a stator in the motor housing (113) by flash evaporation. The refrigeration system (100) according to the present invention can improve the adaptability and universality for different operating conditions, and enhance the overall energy efficiency level of the system.