Compressor Gas Cooling With Backup Cooler for Rankine Circuit Failure

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Solution Overview

Problem

Existing compressor installations with Rankine heat recovery circuits face issues where a failure in the circuit leads to unacceptably high temperatures at the inlet of downstream compressor elements or the compressor installation's output, potentially causing damage due to the loss of cooling function.

Innovation Solution

Incorporating an additional cooler in series with the evaporator, cooled by a separate coolant circuit, to ensure sufficient cooling of the compressed gas even when the Rankine heat recovery circuit fails, allowing the compressor to operate conventionally without heat recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a Rankine heat recovery circuit is used to cool compressed gas, then heat energy is recovered and converted into usable energy, but the system becomes vulnerable to temperature control failure when the circuit breaks down or leaks

Engineering Contradiction:
Improveheat energy lossVSAvoidcooling function reliability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by providing a backup cooling circuit that can immediately take over when the Rankine heat recovery circuit fails. This backup system is pre-configured with coolant circulation paths and heat exchangers positioned to provide redundant cooling capacity, ensuring that temperature control is maintained even when the primary heat recovery system experiences breakdowns or leaks.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent implements parameter changes by switching between different cooling modes - operating with the Rankine circuit for heat recovery, switching to backup cooling mode when the Rankine circuit fails, and potentially adjusting coolant flow rates and temperatures dynamically. This allows the system to adapt its cooling parameters based on the operational status of the heat recovery circuit.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If an additional cooler with separate cooling circuit is added to guarantee cooling when Rankine circuit fails, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvecooling function reliabilityVSAvoidcooling circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the backup cooling circuit to serve multiple functions - it can operate independently when the Rankine circuit is functional to provide supplemental cooling, and it can take over completely when the Rankine circuit fails. The same heat exchangers and coolant circulation systems are used for both heat recovery mode and backup cooling mode, reducing the need for entirely separate dedicated components.

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

Solution Approach 2:

The patent merges the backup cooling functionality with the existing Rankine circuit components where possible. The coolant circulation system shares common elements such as pumps, heat exchangers, and control systems with the Rankine circuit, integrating the backup function into the overall system architecture rather than creating completely separate independent systems.

Inventive Principle:
Principle #5Merging (Combining)

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 guarantees continuous cooling of the compressed gas, preventing temperature increases and ensuring operational safety and efficiency by utilizing the cooling capacity of the additional cooler when the Rankine circuit is offline, allowing the compressor to function as a conventional unit with or without heat recovery.

Implementation Method 1

one or more evaporators that act as a cooler for the compressed gas and in which the liquid working medium coming from the pump is converted into high pressure vapour due to heating by the heat of compression of the compressed gas

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

one or more condensers that are connected to a cooling circuit of a coolant, for example water or air, to enable condensation of the vapour of the working medium into liquid

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

the temperature of a gas increases due to compression

Methodology Applied
Scientific EffectCompression heating: Adiabatic Heating

Data Source

PatentEP3186491B1Method for cooling of the compressed gas of a compressor installation and compressor installation in which this method is applied
Publication Date: 2018.06.06 ATLAS COPCO AIRPOWER NV
  • EP3186491B1 patent drawingFigure 1~2
  • EP3186491B1 patent drawingFigure 3~4
  • EP3186491B1 patent drawingFigure 5~6

AI summary

Compressor installation provided with one or more compressor elements (2) and a heat recovery circuit (11) in the form of a closed Rankine circuit in which a working medium circulates through one or more evaporators (14) that act as a cooler for the compressed gas, and a condenser (16) connected to a cooling circuit (21) for cooling the working medium in the condenser (16), whereby an additional cooler (20) is provided for each evaporator (14) that is connected in series to an evaporator (14) concerned, and which is calculated to be able to guarantee sufficient cooling by itself when the heat recovery circuit (11) is switched off.