Modular SOFC Units Using Waste Heat for Fast Activation
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Solution Overview
Problem
Solid oxide fuel cells require significant heat energy for activation, limiting their efficiency and operational flexibility, especially in mobile applications where quick start-ups and varying power demands are necessary.
Innovation Solution
A fuel cell system with multiple independently operable units, where waste heat from an active unit is used to activate and maintain an inactive unit, reducing the need for additional heating and optimizing power distribution based on current demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the entire fuel cell stack is heated to activate solid oxide fuel cells, then sufficient electrical power can be provided, but a considerable amount of energy (90 kWh or 3 kg of hydrogen) is consumed during heating
Solution Approach 1:
The fuel cell system is divided into multiple independently operable fuel cell units. Each unit can be activated separately using waste heat from other units, eliminating the need to heat the entire stack to 90 kWh. This segmentation allows selective activation of only the necessary number of units based on current power demands.
Solution Approach 2:
The waste heat that would otherwise be lost during operation of active fuel cell units is captured and utilized to activate inactive units. This converts a harmful waste product into a beneficial resource, reducing the overall energy consumption required for system activation and operation.
2Adaptability or versatility
If short operating times are used in mobile applications, then operational flexibility is improved, but solid oxide fuel cells cannot be efficiently operated due to high heating energy requirements
Solution Approach 1:
Multiple independently operable fuel cell units allow the system to be activated quickly by heating only the necessary number of units rather than the entire stack. This segmentation enables short operating times in mobile applications without the prohibitive energy cost of heating a complete large-scale stack.
Solution Approach 2:
Inactive fuel cell units are pre-positioned and can be rapidly activated using waste heat from active units when power demand increases. This preliminary arrangement of multiple ready-to-activate units enables quick response to changing power requirements in mobile applications.
3Power
If the entire heat capacity of the fuel cell stack is heated when only part of the load is required, then sufficient power is available, but energy efficiency deteriorates
Solution Approach 1:
The fuel cell system is divided into multiple independently operable units, allowing only the necessary number of units to be activated based on current load requirements. This segmentation enables the system to provide sufficient power for partial load conditions without heating the entire stack, thereby maintaining energy efficiency.
Solution Approach 2:
Instead of heating the entire fuel cell stack, only the necessary portion (number of units) is activated to meet the current load requirement. This partial action approach avoids the energy waste of heating excess capacity that would remain unused during partial load operations.
4Loss of energy
If multiple independently operable fuel cell units are used, then energy efficiency and operational flexibility are improved, but device complexity increases
Solution Approach 1:
The system uses multiple independently operable fuel cell units with standardized designs. While the number of units increases, each unit maintains a consistent structure and operation protocol, which manages complexity through modular repetition rather than requiring fundamentally different components for each unit.
Solution Approach 2:
Multiple fuel cell units share common infrastructure including waste heat exchange networks, control systems, and balance of plant components. This merging of shared resources reduces the overall complexity that would otherwise result from having completely separate systems for each unit.
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 energy consumption and enables faster start-ups, improved efficiency, and flexible power management, allowing for efficient operation across different power requirements without excessive heat input.
Implementation Method 1
The fuel cell system is designed to provide a quantity of heat for activating a second fuel cell unit of the at least two fuel cell units from waste heat of a first fuel cell unit of the at least two fuel cell units
Implementation Method 2
the required cathode gas, such as, for example, air, is compressed on the cathode side by a blower
Implementation Method 3
preheated by means of a heat exchanger before it reaches the cathode space
Implementation Method 4
Solid oxide fuel cells (SOFC) have hitherto been used mainly in stationary applications. They are distinguished by a high operating temperature and a comparatively high electrical efficiency
Data Source
AI summary
The invention relates to a fuel cell system (200) having at least two fuel cell units (210, 220) that are respectively designed to be operated independently from each other, wherein the fuel cell system (200) is designed to provide an amount of heat for activating a second fuel cell unit (210) of the at least two fuel cell units (210, 220) from waste heat of a first fuel cell unit (220).