Thermal energy storage and heat rejection system

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Solution Overview

Problem

High energy applications require efficient cooling systems that can maintain equipment at a steady temperature, but existing systems are often large, heavy, and ineffective in high ambient temperatures, making them difficult to transport and operate.

Innovation Solution

A cooling system comprising a two-phase pump loop and a vapor compression system with a thermal energy storage that separates the coolant into liquid and gaseous portions, allowing for efficient heat transfer and temperature control, even in high temperature environments, by using a trans-critical vapor compression system and a liquid-vapor separator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous cooling is used to maintain equipment at steady operating temperature, then the equipment performance is maintained, but the cooling system becomes large and heavy making it difficult to transport

Engineering Contradiction:
Improveequipment performance stabilityVSAvoidcooling system weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent merges the thermal energy storage function with the heat rejection function into a single integrated system. The thermal energy storage unit stores excess heat generated during high-power operation, and this stored heat is subsequently rejected to the environment, eliminating the need for separate large cooling systems while maintaining equipment temperature stability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The thermal energy storage unit acts in advance by capturing and storing thermal energy during periods of high heat generation, before the cooling system needs to reject this heat. This preliminary thermal energy capture allows the cooling system to be smaller since it only needs to handle heat rejection during low-power periods rather than continuously managing peak thermal loads

Inventive Principle:
Principle #10Preliminary action

2Temperature

If conventional refrigeration systems are used for cooling, then cooling capability is achieved, but the system cannot cool effectively in areas having high ambient temperatures

Engineering Contradiction:
Improvecooling capabilityVSAvoidenvironmental adaptability
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The system operates in periodic cycles, alternating between thermal energy storage mode during high-power operation and heat rejection mode during low-power operation. This periodic operation allows the system to manage thermal loads effectively even in high ambient temperature environments by rejecting heat during cooler periods

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system changes its operational parameters dynamically, switching between storing thermal energy and rejecting thermal energy based on operational conditions. The thermal energy storage unit allows the system to accumulate heat at certain times and reject it at other times, adapting to varying ambient temperature conditions and maintaining effective cooling capability across different environments

Inventive Principle:
Principle #35Parameter changes

3Productivity

If large cooling systems are used to handle thermal loads, then cooling effectiveness is improved, but the system complexity and size increase

Engineering Contradiction:
Improvecooling effectivenessVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The thermal energy storage unit serves multiple functions: it acts as a heat sink during high-power operation, stores thermal energy for later rejection, and functions as part of the overall thermal management system. This multi-functionality allows the system to achieve effective cooling without requiring separate dedicated components for each function, thereby reducing overall system complexity

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

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

The system effectively absorbs and rejects heat, maintaining equipment within tight temperature tolerances, reduces the size and weight of the cooling system, and allows for easier transportability by utilizing thermal energy storage to manage thermal loads.

Implementation Method 1

a thermal energy storage configured to deliver a liquid portion of a second coolant to the condenser of the two-phase pump loop, wherein the thermal energy storage is configured to separate the second coolant into the liquid portion and a gaseous portion

Methodology Applied
Scientific EffectPhase separation: Phase Change

Implementation Method 2

an evaporator configured to evaporate a first coolant supplied by the pump

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

a condenser configured to condense the first coolant evaporated by the evaporator

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

the compressor is configured to compress the gaseous portion of the second coolant from the thermal energy storage

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 5

the cooler is configured to cool the gaseous portion compressed by the compressor

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 6

The condenser of the two-phase pump loop transfers heat from the first coolant to the liquid portion of the second coolant

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3553421B1Thermal energy storage and heat rejection system
Publication Date: 2023.11.01 ROLLS ROYCE CORP
  • EP3553421B1 patent drawingFigure 1
  • EP3553421B1 patent drawingFigure 2
  • EP3553421B1 patent drawingFigure 3

AI summary

A cooling system is provided including a two-phase pump loop and a vapor compression system. The two-phase pump loop cools a thermal load with a first coolant. The vapor compression system is configured to circulate a second coolant. The vapor compression system includes a liquid vapor separator which separates the second coolant into a liquid portion and a gaseous portion. The liquid vapor separator is a thermal energy storage for the two-phase pump loop. A condenser of the two-phase pump loop transfers heat from the first coolant to the liquid portion of the second coolant in the liquid-vapor separator.