Fuel Cell Cooling System with Antifreeze Loop for Radiator Size Reduction
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Solution Overview
Problem
Fuel cell systems require large radiators to maintain desired water balance at high altitudes and temperatures, and existing cooling systems are inefficient in minimizing radiator size while operating at near ambient pressure and low temperatures.
Innovation Solution
A fuel cell cooling system utilizing a liquid water loop with an antifreeze cooling loop that pressurizes water vapor, condenses it, and separates it from immiscible antifreeze, allowing for higher radiator temperatures and reduced radiator size without increasing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a radiator is designed to reject 70-80 kW of heat while providing a coolant return temperature of less than 60° C., then the fuel cell water balance is maintained, but the radiator size becomes excessively large
Solution Approach 1:
The cooling system is divided into two separate loops: a low-temperature liquid cooling loop for the fuel cell stack and a high-temperature antifreeze cooling loop for the radiator. This segmentation allows each loop to operate at its optimal temperature range, with the heat exchanger serving as the interface between them.
Solution Approach 2:
An intermediate heat exchanger is introduced as a mediator between the liquid cooling loop and the antifreeze cooling loop. This heat exchanger transfers heat from the low-temperature coolant to the high-temperature antifreeze, enabling the radiator to operate at higher temperatures (80-95° C.) while the fuel cell receives cooled liquid at appropriate temperatures.
2Area of stationary object
If the antifreeze cooling loop operates at higher temperatures to minimize radiator size, then the radiator efficiency improves, but the risk of freezing in cold weather increases
Solution Approach 1:
The intermediate heat exchanger acts as a thermal barrier that decouples the radiator operating temperature from the fuel cell coolant temperature. The antifreeze in the radiator loop can be maintained at higher temperatures for efficient heat rejection, while the liquid cooling loop provides the necessary low-temperature cooling for the fuel cell, and the heat exchanger prevents direct mixing of the two fluids.
Solution Approach 2:
The system changes the operating temperature parameter of the radiator by introducing the antifreeze loop. The antifreeze allows the radiator to operate at 80-95° C. without freezing risk, while the separate liquid cooling loop maintains the fuel cell at the required lower temperatures through active cooling control.
3Device complexity
If the fuel cell operates at near ambient pressure, then the system complexity is reduced, but the cooling efficiency at high altitudes and temperatures deteriorates
Solution Approach 1:
The cooling system is segmented into two independent loops that can be optimized separately. The liquid cooling loop operates at near ambient pressure with the fuel cell, simplifying the overall system, while the antifreeze cooling loop is designed specifically for high-altitude and high-temperature conditions with appropriate antifreeze concentration and flow rate control.
Solution Approach 2:
The system changes the operating parameters of each loop independently. The liquid cooling loop maintains near ambient pressure for simplicity, while the antifreeze loop adjusts its temperature and flow parameters to compensate for high-altitude and high-temperature environmental conditions, achieving effective heat rejection without increasing fuel cell operating pressure.
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 achieves high-temperature cooling at near ambient pressure with low fuel cell temperatures, minimizing radiator size and enhancing cooling efficiency by vaporizing water in the first cooling loop and condensing it in the antifreeze loop.
Implementation Method 1
an inductor that receives the water vapor, pressurizes the water vapor and introduces the water vapor to an antifreeze
Implementation Method 2
The antifreeze cooling loop is higher pressure and condenses the water vapor at higher temperatures
Implementation Method 3
Water in the liquid cooling loop exits the fuel cell and passes through a restricting valve thereby lowering the pressure of the water. A flash cooler downstream from the restricting valve collects the water vapor
Implementation Method 4
The water is separated from the antifreeze and returned to the fuel cell cooling loop as liquid water after the mixture of condensed water vapor and antifreeze has passed through a radiator
Data Source
AI summary
A fuel cell cooling system (10) includes a fuel cell (12) having a liquid loop (24) that produces water vapor. An antifreeze cooling loop (38) includes an inductor (40) that receives the water vapor and introduces the water vapor to an antifreeze. The water is separated (48) from the antifreeze and returned to the liquid cooling loop as liquid water (50) after the mixture of condensed water vapor and antifreeze has passed through a radiator (46). Water in the liquid cooling loop (24) exits the fuel cell (12) and passes through a restricting valve (32) thereby lowering the pressure of the water A flash cooler (34) downstream from the restricting valve collects the water vapor and provides it to the inductor (40) in the antifreeze cooling loop (38).