Compressor Heat Medium Flow Path to Suppress Frost Formation

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Solution Overview

Problem

Existing compressor configurations that cool discharge gas by injecting refrigerant liquid into the discharge space can lead to excessive frost formation on the compressor's surface, which is undesirable.

Innovation Solution

Incorporating a heat medium flow path opposite to the discharge space across a partition wall, allowing the flow of a heat medium or lubricant oil to increase the temperature of the compressor casing and suppress frost formation, potentially using a lubricant oil circulation path and oil pump to enhance heat transfer without requiring a dedicated oil cooler.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If refrigerant liquid is injected into the discharge space to cool the compressed discharge gas, then the overheating of the compressor is suppressed, but a large amount of frost occurs on the surface of the compressor

Engineering Contradiction:
Improvetemperature of compressed discharge gasVSAvoidfrost occurrence on compressor surface
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The head cover is divided into two separate spaces: a discharge space for receiving compressed discharge gas and a heat medium storage space for storing heat medium. This segmentation allows independent control of cooling functions, enabling the discharge gas to be cooled without causing frost on the external surface of the compressor.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A heat medium (such as lubricant oil or water) is introduced as an intermediary substance to transfer thermal energy. The heat medium absorbs excess heat from the compressed discharge gas through thermal conduction across the partition wall, preventing direct cooling that would cause frost formation on the compressor surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If cooling water is circulated through pipes in the crankcase or head cover to suppress overheating, then the compressor temperature is controlled, but the system complexity increases

Engineering Contradiction:
Improvecompressor temperature controlVSAvoidcooling system structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The heat medium storage space serves multiple functions: it acts as both a thermal management system for controlling compressor temperature and utilizes the lubricant oil that is already present in the compressor for cooling purposes. This multi-functionality eliminates the need for separate cooling water pipes and reduces system complexity.

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

Solution Approach 2:

The compressor utilizes its own lubricant oil as the heat medium for cooling the compressed discharge gas. The lubricant oil, which is already circulating in the compressor for lubrication purposes, is repurposed to provide thermal management, eliminating the need for additional dedicated cooling systems.

Inventive Principle:
Principle #25Self-service

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

Effectively suppresses frost formation on the compressor's surface by increasing the temperature of the casing and partition wall, improving operational efficiency and reducing costs by eliminating the need for additional cooling components.

Implementation Method 1

a heat medium flow path 20 which allows a heat medium or lubricant oil to flow; by flowing the heat medium through the heat medium flow path, the temperature of the compressor casing 16 which includes the partition wall 18a forming the discharge space Sv is increased

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

cooling a compressed discharge gas with latent heat of vaporization of the refrigerant liquid

Methodology Applied
Scientific EffectEvaporation and latent heat of vaporization: Evaporation

Data Source

PatentEP4187090B1Compressor and compressor system
Publication Date: 2024.11.20 MAYEKAWA MFG CO LTD
  • EP4187090B1 patent drawingFigure 1
  • EP4187090B1 patent drawingFigure 2
  • EP4187090B1 patent drawingFigure 3

AI summary

A compressor according to an embodiment includes: a discharge valve; a discharge space formed downstream of the discharge valve; a liquid injection hole for injecting a refrigerant liquid into the discharge space; and a heat medium flow path located opposite to the discharge space across a partition wall forming the discharge space.