A micro-cogenerator based on a natural gas reformer and a
Polymer Electrolyte Membrane Fuel Cell (PEMFC) is studied,
pointing out the links between different sub-systems. PHD
thesis is conducted within the EPACOP project, which aims at
testing PEMFC systems on user sites to assess development and
acceptance of this technology for small stationary applications.
Five units were installed from November 2002 to May 2003
and have been operated until now, in real life conditions. They
deliver up to 4 kW of AC power and about 6 kW of heat.
Center for Energy and Processes (CEP), one of the
scientific partners, processes and analyses the experimental
data from the five units, running in different regions of France.
This database and the study of the flow sheet enable to propose
changes to enhance the efficiency of the system composed of a
steam-reforming, a shift and a preferential oxidation reactor, a
fuel cell stack and heat exchangers. The steady state modeling
and optimization of the system is done with Thermoptim®, a
software developed within CEP for applied thermodynamics.
At constant power, main targets are to decrease natural gas
consumption, to increase heat recovery and to improve the
water balance. This study is made at full load and partial load,
using a method inspired on pinch point analysis.
Main results of this study are different system
configurations that allow improvement of gross electrical efficiency and thermal efficiency and enable to obtain a
positive water balance.