Air Loop and Thermal management Optimization for fuel cell Systems – ALTOS

Hydrogen is expected to play a major role in the energy transition and the decarbonation of the transportation sector. For automotive applications using fuel cell electrical vehicles FCEV, the propulsion system has to be able to handle a wide range of operating points in steady and transient conditions.
The cost for the balance of plant of a fuel cell system represent roughly 50% of the total cost with a contribution of 25% and 11% respectively for the air loop system and the coolant loops. The efficiency and durability of the fuel cell stacks can be enhanced with the appropriate thermal and energy management of the stack in particular of temperature, humidity and pressure. It can be noted, that the power absorbed by the air compressor can reach 10 to 25% of the net output power of the system. The coolant loops have to ensure in all conditions that the stack is maintained in a given range of temperatures to maximize efficiency and under a given temperature limit to prevent membranes deterioration. With the reduction of the coolant temperature compared to internal combustion engine, this is a major constraint for the design of compact heat exchangers and efficient fans. The design and the understanding of these systems behavior in steady and transient conditions and their interactions have been often overlooked to focus on the electrochemical behavior of the membranes, fuel cell stacks, durability and power electronics.
Building up on the existing and recently developed open source Modelica library VIRTUAL-FCS, the proposed ALTOS project will focus on the design methodology and system modelling of air and cooling loops. It will target systemic optimization of FCEV relying on appropriate design of the auxiliary air and cooling loop components. ALTOS will combine numerical and experimental approaches to provide validated models in steady and transient conditions for the cooling loop and the air loop components and their interactions with the fuel cell system.