Cooling arrangement and method for cooling a compressed-air generator with at least two stages

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Solution Overview

Problem

Existing compressed air generator systems face inefficiencies in cooling and heat recovery, relying on cooling air that often results in heat loss or inefficient recovery, with a need for more effective heat management to avoid overheating and reduce equipment costs.

Innovation Solution

A cooling arrangement for a two-stage compressed air generator using liquid-cooled intercoolers and aftercoolers, along with a liquid-cooled assembly cooler, where a coolant circuit with a main cooler efficiently dissipates heat from the system, allowing for targeted coolant feeding to maintain high temperatures and enable heat recovery through a heat exchanger.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If cooling air is used to cool the compressed air generator, then the cooling system is simple, but heat recovery is inefficient and heat loss occurs

Engineering Contradiction:
Improvecooling system complexityVSAvoidheat loss
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent applies hydraulic cooling by using a liquid coolant (water or water-glycol mixture) instead of air cooling. The coolant circulates through channels in the housing, absorbing heat from the compressed air and components. This hydraulic approach enables efficient heat recovery while maintaining system simplicity, directly resolving the contradiction between cooling system simplicity and heat recovery efficiency.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Productivity

If the coolant temperature is lowered to improve cooling efficiency, then cooling performance increases, but the temperature difference for heat recovery decreases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcoolant temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent segments the cooling function into two separate circuits: a first coolant circuit for heat recovery that maintains higher temperatures, and a second coolant circuit for component cooling that uses lower temperatures. This segmentation allows each circuit to be optimized independently - the first circuit preserves temperature for efficient heat recovery while the second circuit provides aggressive cooling for components, resolving the contradiction between cooling efficiency and heat recovery temperature requirements.

Inventive Principle:
Principle #1Segmentation

3Loss of energy

If a heat exchanger is added to recover heat, then heat recovery efficiency improves, but device complexity increases

Engineering Contradiction:
Improveheat recovery efficiencyVSAvoidcooling arrangement complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The housing serves multiple functions: it contains the compressed air generator, provides cooling channels for the first coolant circuit to enable heat recovery, and houses the second coolant circuit for component cooling. By making the housing multi-functional, the patent achieves efficient heat recovery without adding separate heat exchanger components, thus improving heat recovery efficiency while minimizing increases in device complexity.

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

4Ease of operation

If separate cooling circuits are used for different components, then cooling precision improves, but device complexity increases

Engineering Contradiction:
Improvecooling precisionVSAvoidcooling circuit complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements a dynamic cooling system with a control unit that monitors temperatures and dynamically adjusts coolant flow distribution between the first and second circuits. The control unit can redirect coolant based on real-time thermal conditions, allowing precise cooling control for different components while simplifying the overall system architecture through intelligent control rather than complex fixed infrastructure.

Inventive Principle:
Principle #15Dynamics

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 enhances cooling efficiency, reduces equipment size and costs, and allows for more effective heat recovery, maintaining high temperatures for efficient heat transfer and utilization.

Implementation Method 1

a liquid-cooled intercooler arranged between a first and a second compressor stage to cool the pre-compressed air delivered by the first compressor stage

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a liquid-cooled aftercooler arranged after the second compressor stage to cool the air compressed by it

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

a liquid-cooled sub-cooler is provided to absorb heat from other components of the compressed air generator

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

a main cooler, the cold side of which supplies coolant to the respective coolant inlet of the intercooler, the aftercooler and the sub-cooler, and the hot side of which receives the heated coolant exiting the intercooler and the aftercooler

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3918199B1Cooling arrangement and method for cooling a compressed-air generator with at least two stages
Publication Date: 2023.03.08 GARDNER DENVER DEUTLAND
  • EP3918199B1 patent drawingFigure 1
  • EP3918199B1 patent drawingFigure 2

AI summary

The invention relates to a cooling arrangement for an at least two-stage compressed air generator (01). The cooling arrangement comprises an intercooler (04) which is located between a first and a second compressor stage (02, 03), an aftercooler (05) which is located downstream of the second compressor stage (03), and a component cooler (08) which receives heat from additional components of the compressed air generator (01). A coolant circuit comprises a main cooler (07), the cold side of which supplies a cooled coolant at a low temperature to the coolant inlet of the intercooler (04), to the coolant inlet of the aftercooler (05), and to the coolant inlet of the component cooler (08) in parallel, and the hot side of which receives, at a high temperature, the heated coolant which exits at the coolant outlet of the intercooler (04) and at the coolant outlet of the aftercooler (05) in parallel. The coolant outlet of the component cooler (08) is connected to a feed inlet (12) of the intercooler (04) and/or of the aftercooler (05). The feed inlet (12) is located between the coolant inlet and the coolant outlet at a position at which the intermediate temperature of the coolant in the intercooler (04) and in the aftercooler (05) corresponds to the outlet temperature of the coolant at the component cooler (08) ±20%. The invention also relates to a method for cooling an at least two-stage compressed air generator.