Fuel Cell Circulation Pump Control for Low Temperature Protection
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Solution Overview
Problem
Fuel cell systems face damage to circulation pumps due to freezing at low temperatures, leading to inefficiencies as existing solutions require wasting fuel gas for scavenging, which deteriorates system efficiency.
Innovation Solution
A fuel cell system with a controller that stops the circulation pump at a predetermined low temperature to prevent damage, maintaining sufficient fuel gas concentration without the need for scavenging, thereby improving system efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the circulation pump is driven at low temperature to maintain fuel gas circulation, then the fuel gas concentration is maintained, but the circulation pump may be damaged due to freezing
Solution Approach 1:
The controller stops the circulation pump before freezing can occur by detecting low temperature conditions. This preliminary protective action prevents the harmful freezing effect from damaging the pump, eliminating the need for scavenging operations that would waste fuel gas.
2Reliability
If scavenging processing is performed by introducing dry fuel gas to prevent freezing, then the circulation pump is protected, but fuel gas is wasted and system efficiency deteriorates
Solution Approach 1:
Instead of using scavenging with dry fuel gas, the controller performs preliminary protection by stopping the pump at low temperatures. This eliminates the need for fuel gas waste while still protecting the pump from freezing damage.
Solution Approach 2:
The system uses the temperature detection capability and control logic to automatically manage the pump operation based on environmental conditions, making the protection mechanism self-regulating without requiring additional fuel gas consumption for scavenging.
3Loss of energy
If the circulation pump is stopped at low temperature to prevent damage, then system efficiency is improved by avoiding power loss, but the fuel gas concentration in the fuel off gas may lower
Solution Approach 1:
The controller stops the pump before freezing occurs, and the system maintains adequate fuel gas concentration through the natural composition of fuel off gas at low temperatures where water vapor partial pressure is substantially zero and nitrogen cross leak is minimal.
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 solution effectively prevents pump damage and enhances system efficiency by maintaining fuel gas concentration and reducing power loss at low temperatures, without the need for scavenging, thus improving overall system performance.
Implementation Method 1
the generated water which might remain in the circulation pump or condensed moisture is sometimes frozen
Implementation Method 2
condensed moisture
Implementation Method 3
a water vapor partial pressure in the fuel off gas is substantially zero at the low temperature
Data Source
AI summary
An object of the present invention is to provide a fuel cell system capable of avoiding damage to a circulation pump at a low temperature to improve system efficiency. The fuel cell system of the present invention includes a fuel gas circulation system having a circulation path which re-circulates, through a fuel cell, a fuel off gas discharged from the fuel cell, and a circulation pump which feeds under pressure the fuel off gas in the circulation path; and a controller which controls driving of the circulation pump. The controller stops the driving of the circulation pump at a predetermined low temperature.