Session: 13-01: Hydrogen and Fuel Cells

Paper Number: 156332

156332 - A Study on the Load Analysis and Specific Power Improvement of Fuel-Cell Thermal Management System by Evaporative Cooling 

Abstract: 

Recently, research for using large drones in various fields such as agriculture and transportation has been actively underway. In general, Proton Exchange Membrane Fuel Cell (PEMFC) systems integrated into drones require a cooling system to manage heat dissipation due to the increased load associated with diverse applications. To adopt a water-cooled cooling system while securing sufficient payload, effective utilization of moisture discharged from the fuel cell stack is required. however, directly applying existing library models presents analytical limitations. Additionally, as the number of components in a water-cooled thermal management system increases, the total load also increases. Given the limited payload space in drones, research is needed to reduce the size and weight of the system. In this study, we aim to develop a 20 kWe-class fuel cell system for drones that includes a fuel supply system, an air supply system, and a thermal management system to effectively control the heat generated by electrochemical reactions and simulate the characteristics of PEMFC systems. Additionally, as a weight reduction strategy, we explore the feasibility of applying an evaporative cooling method to the system. Using the AMESet (Adaptive Modeling Environment Sub model editing tool), based on C language, we modeled user-defined functions to represent moisture behavior within the fuel cell and the temperature dynamics of the system, thus creating a sub model for the fuel cell system. This sub model, developed in AMESet, was then converted into a library and applied in the AMESim (Advanced Modeling Environment for Simulation of engineering systems) to simulate the characteristics of the fuel cell system. The fuel supply system is composed of a hydrogen recirculation blower and a mixer, which simulate the recirculation of hydrogen from the fuel cell outlet back into the inlet, representing thermal behavior. The air supply system, comprising a compressor, membrane humidifier, and intercooler, models the thermal behavior of air. The thermal management system consists of a radiator, cooling fan, reservoir, and water pump, simulating the thermal behavior of the coolant that dissipates the heat from electrochemical reactions. A PI controller adjusts the motor speed of the cooling fan and water pump actuators, controlling the fuel cell stack and coolant temperatures to 70°C and 60°C, respectively. To reduce the system weight, we modeled direct water injection onto the radiator in the cooling system to cool the coolant. By applying evaporative cooling, we confirmed that system power consumption decreases, while maintaining the performance of the existing radiator, thereby reducing the system area and weight and improving specific power output.

Presenting Author: Yongjun Yu Chungnam National University

Presenting Author Biography: Yongjun Yoo is a master's student in the Department of Mechanical Engineering at Chungnam National University. My major is mechanical engineering, and I am studying fuel cell systems and heat transfer.