Fitting regression model and experimental validation for a high pressure PEM electrolyzer

Abstract

Hydrogen  production  is  the  main  obstacle  today to  develop  a  real  future  hydrogen  economy.  Research  has focused many efforts in extracting it from clean and renewable sources.     Different     processes     are     analysed:     photolysis, thermochemical  cycles,  algae,  etc;  these  processes  are  still  far from practical use. Electrolysis has represented the most studied and    experimented    area    for    obtaining    hydrogen    without employing fuel cracking. Nevertheless, for its practical storage, the    hydrogen    produced    at    low    pressure    needs    to    be mechanically  compressed,  with  a  high  consumption  of  electric power.   Advanced   materials   and   improved   design   allow   to obtain   hydrogen   from   electrolysis   directly   at   medium-high pressure  (70  bar)  with  no  need  of  mechanical  compression stages.  This  single-step  process  is  more  efficient  than  the  two-step  electrolysis  +  mechanical  compression  process.  In  this paper the authors display the experimental results obtained with a prototype of high pressure PEM electrolyzer manufactured by Giner  Electrochemical  Systems  LLC,  including  the  description of  the  test  bench  for  the  experimental  characterization.  The experimental    design,    based    on    Design    of    Experiments techniques,  studied  the  effect  of  the  main  operation  factors (temperature, pressure, water  flow)  at different levels of power load,  presenting  a  regression  model  of  the  electrolyzer  voltage as a  function of the operating factors, at different values of the electric load.