Fuel Cell Stack Inlet Humidity Control With Post-Humidifier Spray
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Solution Overview
Problem
Fuel cell systems experience reduced power output due to improper humidity levels at the stack air inlet, particularly during transient loading events or in dry-ambient conditions, leading to delays in power delivery.
Innovation Solution
A system and method for controlling humidity at the fuel cell stack air inlet using sensors and a solenoid valve to adjust the water supply from a reservoir to a spray nozzle, ensuring optimal humidity levels by monitoring air and water parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a humidifier is used to increase humidity at the fuel cell stack air inlet, then humidity level is improved, but device complexity increases due to additional control components
Solution Approach 1:
The system employs a humidity sensor positioned at the stack air inlet that provides real-time feedback to the controller. The controller adjusts the solenoid valve operation based on this feedback to maintain optimal humidity levels, creating a closed-loop control system that improves reliability while managing complexity through intelligent control rather than mechanical complexity
Solution Approach 2:
The system uses recovered water from the fuel cell exhaust that would otherwise be wasted. This self-service approach utilizes available resources within the system to achieve humidification, reducing the need for external water sources and simplifying the overall system architecture while maintaining reliable humidity control
2Reliability
If water is sprayed into the air stream to increase humidity, then humidity control is improved, but manufacturing precision is required for proper spray distribution
Solution Approach 1:
The spray nozzle is positioned to deliver water at a specific location in the air stream where it can be effectively distributed. The system applies humidification locally at the point of need rather than requiring uniform distribution throughout the entire system, reducing the precision requirements for the spray nozzle while maintaining effective humidity control
Solution Approach 2:
The system controls the water spray parameters including flow rate, pressure, and timing through the solenoid valve to optimize humidification effectiveness. By dynamically adjusting these parameters based on humidity sensor feedback, the system achieves reliable humidity control without requiring extremely precise manufacturing tolerances for the spray nozzle
3Power
If humidity is increased during transient loading events, then power output is improved, but response time must be reduced to avoid delays
Solution Approach 1:
The system proactively increases humidification before or during transient loading events by detecting changes in operating conditions through the humidity sensor and adjusting water spray accordingly. This preliminary action ensures optimal humidity is available when power demand increases, preventing power delivery delays while maintaining high power output capability
Solution Approach 2:
The system dynamically adjusts the water spray rate and humidification level in real-time based on operating conditions and humidity sensor feedback. This dynamic response allows the system to quickly adapt to transient loading events, optimizing power output while minimizing response time through continuous adjustment rather than static humidification settings
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 provides accurate and efficient humidity control, enhancing fuel cell performance and reducing power delivery delays by utilizing recovered fuel cell exhaust water, thus optimizing power output.
Implementation Method 1
spraying water recovered from the fuel cell stack into the air supplied from a compressor to an intercooler
Implementation Method 2
A solenoid valve is disposed to control flow of water from the reservoir to the spray nozzle
Data Source
AI summary
A method for controlling the humidity of a fuel cell stack air inlet, a fuel cell system in which the method may be exercised, and a fuel cell system controller adapted to execute the method in a fuel cell system. The method for controlling the humidity includes detecting the humidity of air entering a fuel cell stack air inlet downstream a humidifier, detecting the water level of a water reservoir, and using the detected values to control the humidity of air entering the fuel cell stack by controlling a supply of water from the water reservoir to a spray nozzle downstream the humidifier.