Investigation on Thermal Management of Heavy-Duty Commercial FCEV with Focus on Vehicle System Efficiency

The primary approach to meet the objectives of the EU Heavy Duty CO2 Regulation involves decarbonizing the road transport sector by battery electric vehicles (BEV) or hydrogen-fueled vehicles. Even though the well-to-wheel efficiency of hydrogen-fueled powertrains like fuel cell electric vehicles (FCEV) and H2-internal combustion engines (H2-ICE) is much lower in comparison to BEV, they are better suited for on-road heavy-duty trucks, long haul transport missions and regions with scarce charging infrastructure. Hence, this paper focuses on heavy-duty FCEVs and their overall energetic efficiency enhancement by intelligently managing energy transfer across coolant circuit boundaries through waste heat recovery, while ensuring that all relevant components remain within required temperature boundaries under both cold and hot ambient conditions. Results were obtained using a 1D-model that comprises all thermal fluid circuits (refrigerant, coolant, air) created through GT-Suite software. This model was utilized to simulate heat distribution during various road transport missions, such as alpine crossing via Brenner Pass from Munich (Germany) to Modena (Italy). Depending on load cycle profile and ambient conditions significant fuel savings were demonstrated. Furthermore, by coupling the high-temperature circuit of the fuel cell with the low-temperature circuit of the battery via a water/water heat exchanger, there is no need for additional electric heating via an electric heating element (PTC) within this circuit. In more extreme ambient conditions, utilizing recovered heat solely from high-temperature fuel-cell circuit is not sufficient; thus, cabin heating (HVAC) requires further measures such as an additional PTC or system heat pump to achieve an acceptable pull-up time of the cabin.