Dynamic modeling of a proton exchange membrane fuel cell system with a shell-and-tube gas-to-gas membrane humidifier Sanggyu Kang a , Kyoungdoug Min a, *, Sangseok Yu b a School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742, Republic of Korea b Mechanical Engineering, Chungnam National University, Daejeon, Republic of Korea article info Article history: Received 14 November 2011 Received in revised form 9 December 2011 Accepted 11 December 2011 Available online 14 January 2012 Keywords: Gas-to-gas membrane humidifier Shell-and-tube Proton exchange membrane fuel cell Air blower Energy efficient abstract The proton exchange membrane fuel cell (PEMFC) system with a shell-and-tube gas-to-gas membrane humidifier is considered to be a promising PEMFC system because of its energy- efficient operation. However, because the relative humidity of the dry air flowing into the stack depends on the stack exhaust air, this system can be unstable during transients. To investigate the dynamic behavior of the PEMFC system, a system model composed of a lumped dynamic model of an air blower, a two-dimensional dynamic model of a shell- and-tube gas-to-gas membrane humidifier, and a one-dimensional dynamic model of a PEMFC system is developed. Because the water management during transient of the PEMFC system is one of the key challenges, the system model is simulated at the step change of current. The variations in the PEMFC system characteristics are captured. To confirm the superiority of the system model, it is compared with the PEMFC component model during transients. Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. 1. Introduction Proper humidification is one of the key challenges for a proton exchange membrane fuel cell (PEMFC) [1]. When the membrane is not well hydrated, the proton conductivity is decreased, resulting in decreased net performance of the fuel cell stack. However, flooding will occur when the membrane is over hydrated [2e4]. When flooding occurs, the water remaining in the pores of the gas diffusion layer (GDL) blocks the reactant pathway, reducing the chemical reaction rates and causing the over-potential to increase [5]. Moreover, flooding may have detrimental effects on the performance and lifespan of the fuel cell. Therefore, it is important to control the membrane humidity of the fuel cells to avoid dehydration and flooding. Various types of external humidifiers of nozzle spray, gas bubbling, enthalpy wheel, and membrane humidifiers have been developed to attain appropriate fuel cell humidity [6e10]. For the nozzle spray humidifier, the coolant water is atomized and sprayed uniformly on the reactant gases. The gas bubbling humidifier humidifies the reactant gases by passing it through bottles of heated water [11]. In an enthalpy wheel humidifier, the enthalpy of the outlet gas is reused to humidify and warm the inlet dry air by controlling the rota- tional speed of the wheel. These external humidifiers have good humidification performance; however, extra power is needed for operation. In the membrane humidifier, dry gas, which flows through one channel, is humidified and heated by the gas or liquid going through another channel. The membrane humidifier is widely used for gas humidification * Corresponding author. Tel.: þ82 2 880 1661; fax: þ82 2 883 0179. E-mail address: kdmin@snu.ac.kr (K. Min). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 37 (2012) 5866 e5875 0360-3199/$ e see front matter Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijhydene.2011.12.063