Design and Analysis of a Spray Cooling System for a Heavy-Duty Fuel Cell Truck

Polymer electrolyte membrane fuel cells (PEM-FC) are an environmental-friendly alternative to internal combustion engines (ICE) as a power source for commercial vehicles [22]. Fuel cell trucks are able to drive long distances and have short refueling times [31]. A main challenge for fuel cell trucks is the cooling deficit under high-load conditions at hot ambient temperatures. In this study, a spray cooling system for a heavy-duty fuel cell truck is designed with the aim of meeting the cooling demand at highest driving loads. The need for an improved cooling system results from the high amount of waste heat from the PEM-FC that is injected into the cooling system at low coolant temperatures. To analyze the requirements of the cooling system of a fuel cell-powered truck, boundary conditions and load cycles affecting the thermal management are investigated. From there, a spray cooling system is designed. The designed spray cooling system includes an on-board water recovery system that uses the water produced by the PEM-FC. An operating strategy is developed, which includes the collection of water in low- to medium-load driving situations and the use of spray cooling in high-load driving situations. The increase of cooling capacity achieved by using the spray cooling system as an extension of the conventional cooling system is demonstrated by simulation of two high-load driving cycles.