Supplemental cooling systems for fuel cell powered vehicles with liquid hydrogen
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Solution Overview
Problem
Conventional cooling systems for internal combustion engine vehicles are inadequate for fuel cell powered vehicles due to increased heat loads, reduced temperature levels, and electrical conductivity issues, requiring a supplemental cooling system that can meet enhanced heat rejection capabilities and prevent electrical hazards.
Innovation Solution
A cooling system utilizing a liquid hydrogen storage tank, metering pump, hydrogen evaporator heat exchanger, gas accumulator, and a coolant circuit with a regulating valve to control coolant flow, which leverages the heat of vaporization and sensible heat of hydrogen to provide supplemental cooling for hydrogen fuel cell systems, addressing heat rejection and conductivity challenges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional cooling systems are used for fuel cell vehicles, then the system structure is simple, but the heat rejection capability is insufficient
Solution Approach 1:
The patent combines the liquid hydrogen storage system with the cooling system by using the evaporator to simultaneously cool the fuel cell and vaporize liquid hydrogen. This integration allows the cooling system to achieve enhanced heat rejection capability (3-4 times that of conventional systems) while avoiding the need for separate, complex cooling infrastructure.
Solution Approach 2:
The invention changes the operating parameters of the cooling system by utilizing liquid hydrogen at cryogenic temperatures (around -253°C) as the cooling medium. This parameter change enables the system to reject heat at much lower temperatures, dramatically increasing the heat rejection capability according to the Q/ΔT relationship.
2Reliability
If conventional coolant is used, then the cooling system is simple, but electrical conductivity becomes too high causing safety hazards
Solution Approach 1:
The patent extracts the coolant from the conventional liquid-based system and replaces it with gaseous hydrogen that circulates through the fuel cell. This extraction eliminates the electrical conductivity problem inherent in conventional coolants, as hydrogen gas is naturally non-conductive, thereby ensuring electrical safety without requiring complex conductivity control mechanisms.
Solution Approach 2:
The invention changes the physical state and chemical composition of the cooling medium from conductive liquid coolant to non-conductive gaseous hydrogen. This parameter change fundamentally resolves the electrical conductivity issue, making the system inherently safer while maintaining cooling functionality.
3Power
If radiator size is increased to meet heat rejection requirements, then heat rejection capability improves, but packaging becomes difficult
Solution Approach 1:
The patent changes the temperature parameter at which heat rejection occurs by using cryogenic temperatures. This allows the system to achieve 3-4 times the heat rejection capability of conventional systems with a much smaller radiator volume, as the heat transfer efficiency is dramatically improved by the large temperature differential between the fuel cell and the cold hydrogen.
Solution Approach 2:
The invention merges the cooling function with the hydrogen storage and delivery system. The evaporator serves dual purposes: cooling the fuel cell and vaporizing liquid hydrogen for supply to the fuel cells. This integration eliminates the need for a separate, large radiator system.
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 effectively enhances cooling performance for hydrogen fuel cell vehicles, meeting increased heat rejection requirements and preventing electrical hazards by controlling coolant flow and temperature, thereby ensuring efficient operation and safety.
Implementation Method 1
leverages the heat of vaporization and sensible heat of hydrogen to provide supplemental cooling
Implementation Method 2
hydrogen evaporator heat exchanger having an evaporator inlet in fluid communication with the pump outlet
Data Source
AI summary
A cooling system comprises a liquid hydrogen storage tank, a liquid hydrogen metering pump having a pump inlet in fluid communication with the liquid hydrogen storage tank, and a pump outlet, a hydrogen evaporator heat exchanger having an evaporator inlet in fluid communication with the pump outlet, and an evaporator outlet, a hydrogen gas accumulator having an accumulator inlet in fluid communication with the evaporator outlet, and an accumulator outlet, a hydrogen fuel cell system comprising at least one hydrogen fuel cell having a fuel cell inlet in fluid communication with the accumulator outlet, and a coolant circuit comprising a first coolant path disposed in thermal contact with the hydrogen evaporator heat exchanger.