Dual Cooling Circuit for Fuel Cell Thermal Management
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Solution Overview
Problem
Existing fuel cell cooling systems face inefficiencies in both heating and cooling operations, particularly in vehicle applications, due to overdimensioned coolant pumps and complex constructions that increase energy demands and installation space, leading to higher costs and reduced performance.
Innovation Solution
A dual cooling circuit system where the first circuit includes a coolant pump, fuel cell heat exchanger, charge air cooler, and heating unit, allowing independent operation for efficient heating during cold starts and optimized pump efficiency, while the second circuit features a cooling heat exchanger for efficient cooling, with the charge air cooler positioned after the fuel cell heat exchanger to maintain coolant temperature for effective cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coolant pump is designed for the highest load operation of the cooling, then the cooling performance is improved, but the pump becomes overdimensioned for the cold start case and has worse efficiency
Solution Approach 1:
The cooling system is divided into two separate cooling circuits: a first cooling circuit for the fuel cell with a first coolant pump, and a second cooling circuit for the charge air cooler with a second coolant pump. Each pump is sized and optimized for its specific operational requirements, allowing the first pump to operate efficiently during cold starts without being overdimensioned for full cooling load.
Solution Approach 2:
The system dynamically switches between different operational modes by controlling the opening/closing of valve units. During cold starts, the first cooling circuit operates independently with the first pump at optimal efficiency. During full cooling demand, both circuits operate with both pumps engaged, allowing each pump to operate within its efficient range rather than one pump being constantly overdimensioned.
2Speed
If the charge air cooler is arranged before the fuel cell heat exchanger in the small cooling circuit, then rapid heating of the fuel cell is achieved, but the coolant medium is already heated relatively strongly before flowing into the fuel cell heat exchanger which impairs efficient cooling
Solution Approach 1:
The system separates the heating and cooling functions into different operational modes using two independent cooling circuits. The first cooling circuit handles heating during cold starts, while the second cooling circuit handles cooling during regular operation. This segmentation allows each circuit to be optimized for its specific function without compromising the other.
Solution Approach 2:
The system dynamically reconfigures the cooling circuit topology using valve units. During cold starts, valves direct flow through the first cooling circuit for rapid heating. During regular operation, valves redirect flow through the second cooling circuit for efficient cooling, allowing the system to adapt its configuration based on operational requirements.
3Adaptability or versatility
If a complex construction with multiple valve units is used to divide the main cooling circuit into branches, then the cooling arrangement becomes more versatile, but the installation space and control requirements increase
Solution Approach 1:
Instead of using a single complex circuit with multiple valve units to achieve versatility, the invention segments the system into two independent cooling circuits. Each circuit is simple and dedicated to specific functions, reducing the overall number of valve units and control requirements while maintaining versatility through independent operation of the two circuits.
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 configuration enables efficient circulation and heating of the fuel cell with reduced energy consumption, smaller and cost-effective pumps, and improved cooling performance, extending the service life of the fuel cell and reducing thermal stress.
Implementation Method 1
Heat is introduced into the liquid coolant medium in the first cooling circuit by the heating unit
Implementation Method 2
the fuel cell can thus be heated comparatively rapidly using heat from the charge air cooler via the fuel cell heat exchanger
Implementation Method 3
the liquid coolant medium heated in the charge air cooler and the fuel cell heat exchanger is cooled via the cooling heat exchanger
Implementation Method 4
both the charge air cooler and also the fuel cell are then cooled via the fuel cell heat exchanger
Data Source
AI summary
A cooling arrangement for cooling a fuel cell in a fuel cell system is disclosed. The cooling arrangement has at least two fluidically connected cooling circuits in which a liquid coolant medium flows, The first cooling circuit includes a first coolant pump, a fuel cell heat exchanger, a heating unit, and a charge air cooler, which is in heat-exchanging contact with compressed supply air flowing to the fuel cell. The second cooling circuit includes a cooling heat exchanger for cooling the liquid coolant medium. The cooling arrangement includes at least one further coolant pump.