Quantitative study of water level control system in PEM fuel cell separator for conservation of reactant gases

One of the products of the interaction between hydrogen and oxygen in a fuel cell is water. The presence of this product can reduce the efficiency of the fuel cell and causes problems in its operation. The present study aims to introduce a water level control system that can prevent the loss of reactant gases, such as hydrogen and oxygen, by improving the process of separation of water from these gases. Thus, unused gases are returned to the fuel cell, and as a result, the costs of using the reactant gases for producing electric power will be reduced. Although the process of a control system has been described qualitatively in previous studies, this paper is intended to quantify this procedure with respect to fuel cell specifications and construction limitations. This system consists of mechanical (venturi) and control units and is designed based on different reactant gases such as air and oxygen. The fuel cell pressure drop and maximum wasted volume of gases when using this system are less than 0.001 bar and 0.5% in each cycle, respectively. This system is simulated based on different fuel cell operating pressures.