Integrated Power and Cooling Cycle for Aircraft Waste Heat Recovery

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Solution Overview

Problem

Gas turbine engines face inefficiencies in power utilization and cooling systems, with existing technologies not effectively leveraging waste heat for enhanced performance.

Innovation Solution

A system integrating a power cycle and a cooling cycle, utilizing a recuperative heat exchanger, waste-heat heat exchanger, and ram-air heat exchangers to convert waste heat into electrical power and cooling, with a working fluid like supercritical carbon dioxide or helium, that pressurizes, heats, and cools the fluid to drive a turbine and cool aircraft ambient air.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If waste heat is not utilized, then the system is simpler, but energy efficiency is poor and fuel consumption is high

Engineering Contradiction:
Improveenergy efficiencyVSAvoidsystem complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent converts waste heat from the gas turbine engine into useful power and cooling by integrating a power cycle with a cooling cycle. The waste heat heats the working fluid in the power cycle, driving the turbine to generate power, while the cooling cycle provides aircraft cooling. This transforms the harmful waste heat into beneficial outputs, resolving the contradiction between energy efficiency and system complexity.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent merges the power generation function and cooling function into a single integrated system. The power cycle and cooling cycle share common components such as heat exchangers and the working fluid loop, allowing waste heat to simultaneously drive power generation and provide cooling capacity. This consolidation improves energy efficiency while managing system complexity through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

2Weight of moving object

If separate power and cooling systems are used, then system functions are reliable, but system weight increases and power density decreases

Engineering Contradiction:
Improvesystem weightVSAvoidsystem reliability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent combines separate power and cooling systems into an integrated dual-cycle system that shares common infrastructure including heat exchangers, working fluid loops, and control systems. This merging reduces overall system weight while maintaining the reliability of both power generation and cooling functions through coordinated operation and shared critical components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated system provides multiple functions simultaneously: the power cycle generates electrical power from waste heat, the cooling cycle provides aircraft cooling, and both cycles can operate independently or in coordination. This multi-functionality reduces the need for separate dedicated systems, thereby reducing weight while ensuring reliability through functional redundancy and flexibility.

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

3Loss of energy

If traditional cooling systems are used, then cooling is provided, but power utilization is inefficient and fuel consumption increases

Engineering Contradiction:
Improvepower utilization efficiencyVSAvoidfuel consumption
Core Design Contradiction:
Loss of energyVSUse of energy by moving object

Solution Approach 1:

The patent captures waste heat that would otherwise be lost and converts it into useful power generation through the turbine. The waste heat heats the working fluid, driving the turbine to produce electrical power, while the cooling cycle utilizes the same heat source for aircraft cooling. This conversion reduces fuel consumption by maximizing the utilization of thermal energy from the gas turbine exhaust.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent recovers waste heat from the gas turbine engine exhaust and redirects it through the power cycle and cooling cycle heat exchangers. Instead of discarding the thermal energy in the exhaust, the system recovers it to drive the turbine and provide cooling, thereby improving power utilization efficiency and reducing overall fuel consumption.

Inventive Principle:
Principle #34Discarding and recovering

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 integration improves engine efficiency, reduces fuel consumption, and enhances cooling capabilities, leading to increased power density and reduced weight, while simplifying aircraft systems by consolidating power and cooling functions.

Implementation Method 1

a recuperative heat exchanger configured to receive the working fluid from the first compressor in a first pass and heats the first pass of the working fluid from the first compressor

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a waste-heat heat exchanger configured to receive the working fluid from the first pass of the recuperative heat exchanger and further heat the working fluid from the first pass of the recuperative heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

The turbine is configured to receive the working fluid from the waste-heat heat exchanger, and wherein the working fluid from the waste-heat heat exchanger drives the turbine, the drive shaft, and the first compressor

Methodology Applied
Scientific EffectTurbine expansion: Turbine

Implementation Method 4

A first pass through a ram-air heat exchanger configured to receive the second pass of the working fluid from the recuperative heat exchanger and further cool the second pass of the working fluid from the recuperative heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 5

A pump is configured to receive the portion of the working fluid from the second ram-air heat exchanger and pressurize the portion of the working fluid from the second ram-air heat exchanger

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 6

An isenthalpic valve is configured to receive the portion of the working fluid from the third ram-air heat exchanger and expand the portion of the working fluid from the third ram-air heat exchanger

Methodology Applied
Scientific EffectIsenthalpic expansion: Joule-Thomson Effect

Implementation Method 7

An ambient air heat exchanger configured to receive the portion of the working fluid from the isenthalpic valve and cool the ambient air of an aircraft at altitude via the portion of the working fluid from the isenthalpic valve

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 8

A second compressor is configured to receive the portion of the working fluid from the ambient air heat exchanger pressurize the portion of the working fluid from the ambient air heat exchanger

Methodology Applied
Scientific EffectCompression: Gas Compressor

Data Source

PatentEP3945202A1Power and cooling unit (PCU)
Publication Date: 2022.02.02 HAMILTON SUNDSTRAND CORP
  • EP3945202A1 patent drawingFigure 1
  • EP3945202A1 patent drawingFigure 2
  • EP3945202A1 patent drawingFigure 3

AI summary

A system includes a power cycle and a cooling cycle. The power cycle includes a first compressor (12), a recuperative heat exchanger (14), a waste-heat heat exchanger (16), and a turbine (18). The turbine (18) includes a drive shaft coupled to the first compressor. The working fluid from the waste-heat heat exchanger (16) drives the turbine (18), the drive shaft, and the first compressor (12). The recuperative heat exchanger (14) cools the working fluid from the turbine (18), and at least one ram-air heat exchanger further cools the working fluid from the recuperative heat exchanger (14). The first compressor (12) is configured to pressurize the working fluid from the at least one ram-air heat exchanger. The cooling cycle includes a pump (32), an isenthalpic valve (36), an ambient air heat exchanger (38), and a second compressor (40). The cooling cycle cools the working fluid and ambient air and is connected to the power cycle in the at least one ram-air heat exchanger.