Electronics cooling using lubricant return for a shell-and-tube style evaporator

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Solution Overview

Problem

Existing refrigeration chillers face challenges in maintaining adequate lubricant supply to compressor surfaces due to lubricant mixing with refrigerant, leading to reduced viscosity and pressure drops, which are not effectively addressed by traditional lubricant separators.

Innovation Solution

The refrigeration system incorporates a heat exchanger that creates a thermosiphon effect, ensuring the lubricant-liquid refrigerant mixture is returned to the compressor, improving lubrication and viscosity while minimizing parasitic losses by routing the lubricant return line through the heat exchanger, which enhances the quality and temperature of the lubricant.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lubricant separator is used immediately downstream of the compressor, then lubricant can be separated from the refrigerant, but the separated lubricant has reduced viscosity due to mixed refrigerant and experiences pressure drop

Engineering Contradiction:
Improvelubricant separation effectivenessVSAvoidpressure drop and viscosity loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts lubricant from the refrigerant stream at the evaporator outlet rather than immediately after compression. By positioning the separation point where refrigerant and lubricant naturally stratify in the evaporator, the system removes lubricant in a relatively pure state without the need for high-pressure separation equipment, thus avoiding both pressure drop and viscosity degradation

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The evaporator serves as an intermediary device that facilitates natural lubricant separation through its internal geometry and flow patterns. The evaporator's structure allows lubricant to settle and separate from refrigerant before the mixture reaches the suction line, using the evaporator as a passive separation medium rather than requiring an active separator component

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If lubricant is continuously circulated with refrigerant, then compressor lubrication is maintained, but lubricant viscosity decreases and parasitic losses increase

Engineering Contradiction:
Improvecompressor lubricationVSAvoidparasitic losses and viscosity reduction
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system discards lubricant from the refrigerant stream at the evaporator outlet where it has separated naturally, then recovers this lubricant by routing it through the heat exchanger for temperature conditioning before returning it to the compressor. This continuous recovery process maintains lubricant quality and viscosity while ensuring adequate compressor lubrication

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The patent changes the temperature parameter of the lubricant by routing it through the heat exchanger where it is cooled by the refrigerant. This temperature adjustment optimizes lubricant viscosity for compressor operation, ensuring proper lubrication while minimizing energy losses associated with high-temperature lubricant

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 solution effectively improves compressor lubrication, reduces noise, and maintains a higher viscosity of the lubricant, ensuring efficient operation and minimizing parasitic losses by ensuring a consistent and high-quality lubricant supply.

Implementation Method 1

The refrigeration system incorporates a heat exchanger that creates a thermosiphon effect, ensuring the lubricant-liquid refrigerant mixture is returned to the compressor

Methodology Applied
Scientific EffectThermosiphon effect: Thermosyphon

Implementation Method 2

The heat exchanger that creates a thermosiphon effect... routing the lubricant return line through the heat exchanger, which enhances the quality and temperature of the lubricant

Methodology Applied
Scientific EffectNatural convection: Free Convection

Data Source

PatentEP2828590B1Electronics cooling using lubricant return for a shell-and-tube style evaporator
Publication Date: 2019.10.09 TRANE INTERNATIONAL INC
  • EP2828590B1 patent drawingFigure 1~2
  • EP2828590B1 patent drawingFigure 3~4
  • EP2828590B1 patent drawingFigure 5~6

AI summary

A refrigeration system that induces lubricant-liquid refrigerant mixture flow from a flooded or falling film evaporator by means of the lubricant-liquid refrigerant mixture flow adsorbing heat from an electronic component.