System design of a hydrogen-powered fuel cell for all terrain-vehicles (ATVs)

Abstract

The idea for this thesis was to design a specification of requirements for a hydrogen fuel cell system for golf cart (ATV). The fuel cell was intended to produce power requirements for ATV propulsion system and to replace existing system of golf cart and hence this system should be capable of delivering required power demand for ATV. The existing ATV powered by an internal combustion engine have conventional issues related to GHG emissions and air pollution which is making them less demandable. Hydrogen-powered fuel cell uses hydrogen as a fuel to produce electrical power. This electrical power comes out as a result of electrochemical reaction in the fuel cell where oxygen from air is used as an oxidant. In order to develop specification of requirements 4.8kW, 48V fuel cell was chosen for ATV need and hydrogen composition of 99.99% was selected. The calculations for fuel cell stack parameters and operating conditions were performed using the empirical formulas and modelling fuel cell using basic laws of conservation. Number of fuel cell in fuel stack was found to be 69. Calculations for the water and heat management was performed based on the operating temperature and pressure which in this study was chosen to be 60C and 1.5bar respectively. Based on the findings the external humidification is required for air supply subsystem to achieve 100% humidity for exit air. The required air flow rate was achieved using low pressure blower and for humidification needs humidifiers were installed in hydrogen and air supply subsystems. The hydrogen subsystem is designed with feedback loop of hydrogen recirculation to compensate for the inert gases that move from cathode to anode. The measured parameters were than analyzed and a MATLAB Simulink model was developed to study the behaviour of fuel cell. MATLAB Simulink model developed shows that by decreasing the maximum limit of fuel flow rate from 85lpm (standard liter per min) to 70lpm the stack efficiency increases from 37% to 41% which is acceptable compared to the measured theoretical efficiency of 47%.