Fuel Cell Exhaust Air Recirculation for Cold Inlet Temperature Control
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Solution Overview
Problem
Forklifts powered by lead-acid batteries face issues such as reduced performance, lengthy recharging times, environmental pollution, and the generation of acid mist, while fuel cell systems offer advantages like higher energy density and rapid refueling but require solutions to maintain inlet air temperature in varying environments.
Innovation Solution
A fuel cell air recirculation system with a hinged door in the exhaust air shroud diverts excess heat back to the inlet to maintain temperature, using a system controller to adjust the door's angle based on temperature sensors for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heater is introduced into the fuel cell system to warm incoming air when inlet air temperature falls below threshold, then the inlet air temperature can be maintained above the predetermined level, but this entails additional expenses, intricacies, and impacts performance
Solution Approach 1:
The patent recycles exhaust air that contains excess heat from the fuel cell stack and redirects it back to the inlet air stream. This converts the potentially harmful waste heat into a beneficial heating source, maintaining inlet air temperature without requiring additional heating equipment.
Solution Approach 2:
The system uses its own exhaust air containing thermal energy to heat its own inlet air, creating a self-sustaining thermal management system that does not require external energy sources or additional heating components.
2Temperature
If a heater is introduced into the fuel cell system to warm incoming air, then the inlet air temperature can be maintained above the predetermined level, but this entails additional expenses
Solution Approach 1:
The patent recycles exhaust air that contains excess heat from the fuel cell stack and redirects it back to the inlet air stream. This converts the potentially harmful waste heat into a beneficial heating source, maintaining inlet air temperature without requiring additional heating equipment.
Solution Approach 2:
The system recovers thermal energy from the exhaust air that would otherwise be discarded and reuse it to heat the inlet air, eliminating the need for additional energy input and reducing operational costs.
3Weight of moving object
If additional weights are incorporated to achieve weight equivalent to lead-acid battery, then vehicle performance can be maintained, but the system becomes more complex
Solution Approach 1:
The patent integrates multiple components (fuel cell stack, air recirculation system, exhaust air redirection mechanism) into a unified system that replaces the lead-acid battery while maintaining weight equivalence. The consolidation of thermal management functions within the existing structure reduces overall system complexity despite the added 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
Maintains fuel cell inlet air temperature above a threshold, enhancing performance and efficiency in diverse conditions, including industrial freezers, without additional heating costs or complexity.
Implementation Method 1
a first fan configured to dissipate excess heat generated during electrochemical reactions that occur within a fuel cell stack of a fuel cell system and to direct exhaust air of the fuel cell system
Implementation Method 2
the hinged door is configured to divert exhaust air from the first fan to an inlet of the fuel cell stack to keep an inlet air temperature of the fuel cell stack above a predetermined temperature level
Data Source
AI summary
A system includes a first fan configured to dissipate excess heat generated during electrochemical reactions that occur within a fuel cell stack of a fuel cell system and to direct exhaust air of the fuel cell system. A first air shroud surrounds the first fan, and the first air shroud includes a hinged door. The hinged door is configured to divert exhaust air from the first fan to an inlet of the fuel cell stack to keep an inlet air temperature of the fuel cell stack above a predetermined temperature level.