Analysis Of Fuel Cell Applied For Submarine Air Independent Propulsion (Aip) System

Abstract

In this paper, the performance of a 2000-ton hybrid AIP system submarine is investigated by analyzing the weight, volume and efficiency of its propulsion system. The engine of the investigated AIP system employs a low temperature polymer electrolyte membrane fuel cell which makes use of the hydrogen and oxygen as the reactants. More specifically, the reactants of fuel cell in this study are considered from the combination of three fuel storage systems, methanol (MeOH), liquid hydrogen (LH2) and metal hydride (MH2), and two oxidant storage systems, liquid oxygen (LOX) and compressed oxygen (O-2). Based on the assumed various daily propulsion load consumptions, a propulsion system of a 3500 kW diesel generator, a 300 kW fuel cell, and a 7500 kWh energy capacity Li-ion battery bank is determined. With the system installed in the submarine, the maximum designed endurance can reach a total of 26 days for the fuel cell using the combination of reactant LH2 + LOX, and the minimum designed endurance can be up to 10 days for using the reactant MH2 + O-2. For submarine cruising at zero speed, the submerged endurance of the AIP system using reactant LH2 + LOX plus battery bank is 22.8 times of that using battery bank alone. This value will increase to 25.0 times for submarine cruising at 7.4 knots. At the cruising speed of 5.5 knots, the maximum submerged range of submarine increases a factor of 24.1 for fuel cell using the reactant of LH2 + LOX as compared with operation on battery bank alone. Therefore, the submerged endurance is substantial enhanced for using the combination of fuel cell and battery. In addition, the indiscretion ratio is zero for the AIP system submarine with a cruising speed below 7.1 knots; this can greatly reduce the submarine vulnerability. Based on the weight and volume analysis of the submarine equipped with a hybrid AIP system, the usage of the reactant LH2 + LOX is well suited for a small- to medium-sized 2000-ton submarine with a fuel cell system. Furthermore, using the reactant MeOH + LOX has the advantage for large-sized LT-PEMFC AIP system submarines.