Fuel Cell Thermal Management via Ambient Coolant
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Solution Overview
Problem
Conventional thermal management systems for fuel cells, especially in weight-constrained applications like aircraft, are inefficient due to the need for excess reactant storage and additional cooling subsystems, leading to increased weight and complexity.
Innovation Solution
A system utilizing ambient air or water as a separate coolant to absorb heat from the fuel cell, with the option to recirculate heated coolant to prevent thermal shock and generate additional electricity through a turbine-driven compressor or generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If excess reactant is circulated through the fuel cell to absorb heat, then the fuel cell temperature is controlled, but the weight of the system increases due to storing excess reactant
Solution Approach 1:
A heat exchanger is introduced as an intermediary component to transfer heat from the fuel cell to the reactant stream without requiring the reactant to be physically circulated through the cell. The heat exchanger mediates the thermal energy transfer, allowing temperature control while avoiding the weight penalty of excess reactant storage and circulation systems
Solution Approach 2:
The thermal management function is segmented into separate components: the fuel cell remains dedicated to electrochemical reactions, while a separate heat exchanger subsystem handles thermal management by transferring heat to the reactant stream. This segmentation eliminates the need for excess reactant circulation through the cell itself
2Temperature
If gases exiting the fuel cell are recirculated back to incoming reactant stream for cooling, then cooling is achieved, but the control system complexity and vehicle thermal load increase
Solution Approach 1:
A heat exchanger serves as an intermediary that enables cooling by transferring heat from exhaust gases to the incoming reactant stream without requiring direct recirculation of gases back to the inlet. This eliminates the need for complex recirculation control systems while achieving the same cooling effect
Solution Approach 2:
The cooling function is extracted from the recirculation system and implemented through a separate heat exchanger subsystem. This extraction eliminates the need for complex gas recirculation control while maintaining effective cooling through thermal energy transfer
3Temperature
If a separate closed system cooling loop is used to circulate coolant through the fuel cell, then thermal management is achieved, but the system weight and complexity increase due to additional pumps, coolant, lines, and power consumption
Solution Approach 1:
The cooling function is merged with the existing reactant delivery system by using the reactant stream itself as the coolant medium in a heat exchanger. This eliminates the need for a separate closed-loop cooling system with its own pumps, coolant reservoirs, and piping infrastructure
Solution Approach 2:
The reactant stream serves multiple functions: it provides fuel for the electrochemical reaction and simultaneously acts as the coolant medium for thermal management through the heat exchanger. This multi-functionality eliminates the need for dedicated cooling system components
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 approach reduces weight and complexity by leveraging ambient coolant for thermal management, allowing for efficient heat transfer and power generation, thereby enhancing the overall efficiency and flexibility of the fuel cell system.
Implementation Method 1
The coolant flows through the fuel cell to absorb heat before being discharged and directed away from the fuel cell
Implementation Method 2
The heated coolant is also recirculated into the incoming ambient coolant to increase the temperature of the ambient coolant before it enters the fuel cell to prevent damaging the fuel cell through thermal shock
Implementation Method 3
Embodiments additionally provide for directing the heated coolant from the fuel cell to a turbine, which in turn may be used to drive a generator for creating additional electricity or to drive the compressor
Data Source
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AI summary
Systems and methods provide for the thermal management of a high temperature fuel cell. According to embodiments described herein, a non-reactant coolant is routed into a fuel cell from a compressor or a ram air source. The non-reactant coolant absorbs waste heat from the electrochemical reaction within the fuel cell. The heated coolant is discharged from the fuel cell and is vented to the surrounding environment or directed through a turbine. The energy recouped from the heated coolant by the turbine may be used to drive the compressor or a generator to create additional electricity and increase the efficiency of the fuel cell system. A portion of the heated coolant may be recycled into the non-reactant coolant entering the fuel cell to prevent thermal shock of the fuel cell.