Cooling of the fuel cell drive is one of the key tasks for vehicle applications. The exhaust gas of the fuel cell does not drag along any significant heat flow. Thus, the heat flow to be dissipated by the cooling system is approximately doubled compared to that of the combustion engine. The other reason is the low coolant temperature in PEM fuel cells, which are always used in vehicle drives. It is crucial that a sufficient air mass flow be available to accomplish the required cooling. An important criterion to assess whether or not the volume of the cooling air limits the cooling power is the exchange rate of a heat exchanger. Another significant criterion besides the exchange rate is the expenditure of flow rate required to achieve this exchange rate. In this paper deductions are made about what kind of actions can be taken to increase cooling performance: 1. Optimization of the Cooling Module configuration - thermodynamic considerations: flow guidance, interaction of the main radiator and low temperature radiator. 2. Optimization of the Cooling Module configuration - aerodynamic considerations: distribution into cooling surfaces impinged by dynamic pressure and fans, high performance fans and fan drives. 3. Examples of manufactured cooling modules are described: DaimlerChrysler Class A; DaimlerChrysler Sprinter. The fundamental thermodynamic considerations show that the required increase cannot be achieved using heavy-duty cooling systems alone, at least not in serial vehicles where the available housing space as well as the shape and weight of the cooling system is limited. The power required by radiator fans increases exponentially and will thus reduce the total efficiency of a vehicle. For this reason, an increase in the operating temperature of PEM fuel cells would be indispensable in keeping the cost of the cooling system within economically sensible limits.
Cooling modules for vehicles with a fuel cell drive
Kühlmodule für Fahrzeuge mit Brennstoffzellenantrieb
Fuel Cells ; 3 , 3 ; 153-158
2003
6 Seiten, 9 Bilder, 1 Tabelle, 5 Quellen
Article (Journal)
English
Cooling Modules for Vehicles with a Fuel Cell Drive
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